Systems and methods to monitor an access gateway

The present invention is directed towards systems and methods for monitoring an access gateway. The systems and methods include monitors on appliances that generate and send requests to logon agents or login page services on access gateways. Based on the responses from the logon agents or login page services, the monitors determine whether the logon agents or login page services are available.

FIELD OF THE INVENTION

The present application generally relates to monitoring an access gateway. In particular, the present application relates to systems and methods for monitoring a logon agent or login page service to determine if the logon agent or page service is available.

BACKGROUND OF THE INVENTION

When a user at a client device wishes to access resources on a remote access server, logon agents and login page services can facilitate the authentication and authorization required before such access will be granted. However, the logon agents and login page services may become unavailable or may operate improperly. As a result, a user may waste time attempting to connect to an unavailable agent or service. Further, if the agent or service is operating improperly, the user may repeatedly attempt to obtain authorization through a webpage incapable of facilitating the desired authorization.

BRIEF SUMMARY OF THE INVENTION

The present application is directed towards systems and methods for monitoring an access gateway. The systems and methods include monitors on appliances that generate and send requests to logon agents or login page services on access gateways. Based on the responses from the logon agents or login page services, the monitors determine whether the logon agents or login page services are available.

In one aspect, the present solution is directed to a method for monitoring by an intermediary device a status of a login page service of an access gateway to a plurality of remote access servers. The method includes generating, by a monitor of an intermediary device between a plurality of a clients and an access gateway to a plurality of remote access servers, a first request to access a login page service of the access gateway. The method also includes transmitting, by the intermediary device, the generated first request to the login page service of the access gateway. The method also includes determining, by the monitor, that a first response from the login page service to the first request identifies a successful response and at least one of a plurality of predetermined hidden fields. The method also includes identifying, by the monitor, a status of the login page service as available responsive to the determination. The method also includes transmitting, by the intermediary device, a generated second request to the login page service of the access gateway. The method also includes determining, by the monitor, that a second response from the login page service to the second request does not identify at least one of the plurality of predetermined hidden fields. Lastly, the method also includes identifying, by the monitor, the status of the login page service as unavailable responsive to the determination.

The monitor may generate for the first request a HyperText Transfer Protocol GET request of a logon point provided by the login page service. The monitor may specify the logon point in the generated first request based on a configuration setting of the intermediary service. The monitor may generate the first request to include user agent information. The monitor may generate the first request to include an IP address hosted by the intermediary device. The intermediary device may transmit the first and/or second generated requests at a predetermined frequency.

The monitor may determine that the first response comprises two predetermined hidden fields. The monitor may determine that the second response does not include any of the plurality of predetermined hidden fields. The monitor may determine that the second response does not include a selected one of the plurality of predetermined hidden fields.

In another aspect, the present solution is directed to a method for monitoring by an intermediary device a status of a login agent of an access gateway to a plurality of remote access servers. The method includes generating, by a monitor of an intermediary device between a plurality of a clients and an access gateway to a plurality of remote access servers, a first post request to a logon agent of the access gateway, the first post request identifying a logon point and a version of the logon agent. The method also includes transmitting, by the intermediary device, the generated first post request to the login agent of the access gateway. The method also includes determining, by the monitor, that a first response from the logon agent to the first request includes a predetermined string identifying a successful response. The method also includes identifying, by the monitor, a status of the logon agent as available responsive to the determination. The method also includes transmitting, by the intermediary device, a generated second post request to the logon agent of the access gateway. The method also includes determining, by the monitor, that a second response from the login page service to the second request does not include the predetermined string. Lastly, the method includes identifying, by the monitor, the status of the logon agent as unavailable responsive to the determination.

The monitor may generate for the first request a HyperText Transfer Protocol PUSH request to the identified logon point. The monitor may specify the logon point in the generated first push request based on a configuration setting of the intermediary service. The first request may identify a MAC address of the intermediary device or a source IP address routable to the intermediary device. The intermediary device may transmit the first push request and/or the second push request at a predetermined frequency.

The monitor may determine that the first response includes a string within XML formatted values indicating the response was successful. The monitor may determine that the second response includes an error message. The monitor may determine that the second response does not include a string within XML formatted values indicating the response was successful.

DETAILED DESCRIPTION OF THE INVENTION

For purposes of reading the description of the various embodiments below, the following descriptions of the sections of the specification and their respective contents may be helpful:Section A describes a network environment and computing environment which may be useful for practicing embodiments described herein;Section B describes embodiments of systems and methods for delivering a computing environment to a remote user;Section C describes embodiments of systems and methods for accelerating communications between a client and a server;Section D describes embodiments of systems and methods for virtualizing an application delivery controller;Section E describes embodiments of systems and methods for providing a multi-core architecture and environment; andSection F describes embodiments of systems and methods for monitoring an access gateway in a multi-core system.
A. Network and Computing Environment

Prior to discussing the specifics of embodiments of the systems and methods of an appliance and/or client, it may be helpful to discuss the network and computing environments in which such embodiments may be deployed. Referring now toFIG. 1A, an embodiment of a network environment is depicted. In brief overview, the network environment comprises one or more clients102a-102n(also generally referred to as local machine(s)102, or client(s)102) in communication with one or more servers106a-106n(also generally referred to as server(s)106, or remote machine(s)106) via one or more networks104,104′ (generally referred to as network104). In some embodiments, a client102communicates with a server106via an appliance200.

AlthoughFIG. 1Ashows a network104and a network104′ between the clients102and the servers106, the clients102and the servers106may be on the same network104. The networks104and104′ can be the same type of network or different types of networks. The network104and/or the network104′ can be a local-area network (LAN), such as a company Intranet, a metropolitan area network (MAN), or a wide area network (WAN), such as the Internet or the World Wide Web. In one embodiment, network104′ may be a private network and network104may be a public network. In some embodiments, network104may be a private network and network104′ a public network. In another embodiment, networks104and104′ may both be private networks. In some embodiments, clients102may be located at a branch office of a corporate enterprise communicating via a WAN connection over the network104to the servers106located at a corporate data center.

The network104and/or104′ be any type and/or form of network and may include any of the following: a point to point network, a broadcast network, a wide area network, a local area network, a telecommunications network, a data communication network, a computer network, an ATM (Asynchronous Transfer Mode) network, a SONET (Synchronous Optical Network) network, a SDH (Synchronous Digital Hierarchy) network, a wireless network and a wireline network. In some embodiments, the network104may comprise a wireless link, such as an infrared channel or satellite band. The topology of the network104and/or104′ may be a bus, star, or ring network topology. The network104and/or104′ and network topology may be of any such network or network topology as known to those ordinarily skilled in the art capable of supporting the operations described herein.

As shown inFIG. 1A, the appliance200, which also may be referred to as an interface unit200or gateway200, is shown between the networks104and104′. In some embodiments, the appliance200may be located on network104. For example, a branch office of a corporate enterprise may deploy an appliance200at the branch office. In other embodiments, the appliance200may be located on network104′. For example, an appliance200may be located at a corporate data center. In yet another embodiment, a plurality of appliances200may be deployed on network104. In some embodiments, a plurality of appliances200may be deployed on network104′. In one embodiment, a first appliance200communicates with a second appliance200′. In other embodiments, the appliance200could be a part of any client102or server106on the same or different network104,104′ as the client102. One or more appliances200may be located at any point in the network or network communications path between a client102and a server106.

In some embodiments, the appliance200comprises any of the network devices manufactured by Citrix Systems, Inc. of Ft. Lauderdale Fla., referred to as Citrix NetScaler devices. In other embodiments, the appliance200includes any of the product embodiments referred to as WebAccelerator and BigIP manufactured by F5 Networks, Inc. of Seattle, Wash. In another embodiment, the appliance205includes any of the DX acceleration device platforms and/or the SSL VPN series of devices, such as SA 700, SA 2000, SA 4000, and SA 6000 devices manufactured by Juniper Networks, Inc. of Sunnyvale, Calif. In yet another embodiment, the appliance200includes any application acceleration and/or security related appliances and/or software manufactured by Cisco Systems, Inc. of San Jose, Calif., such as the Cisco ACE Application Control Engine Module service software and network modules, and Cisco AVS Series Application Velocity System.

In one embodiment, the system may include multiple, logically-grouped servers106. In these embodiments, the logical group of servers may be referred to as a server farm38. In some of these embodiments, the serves106may be geographically dispersed. In some cases, a farm38may be administered as a single entity. In other embodiments, the server farm38comprises a plurality of server farms38. In one embodiment, the server farm executes one or more applications on behalf of one or more clients102.

The servers106within each farm38can be heterogeneous. One or more of the servers106can operate according to one type of operating system platform (e.g., WINDOWS NT, manufactured by Microsoft Corp. of Redmond, Wash.), while one or more of the other servers106can operate on according to another type of operating system platform (e.g., Unix or Linux). The servers106of each farm38do not need to be physically proximate to another server106in the same farm38. Thus, the group of servers106logically grouped as a farm38may be interconnected using a wide-area network (WAN) connection or medium-area network (MAN) connection. For example, a farm38may include servers106physically located in different continents or different regions of a continent, country, state, city, campus, or room. Data transmission speeds between servers106in the farm38can be increased if the servers106are connected using a local-area network (LAN) connection or some form of direct connection.

Servers106may be referred to as a file server, application server, web server, proxy server, or gateway server. In some embodiments, a server106may have the capacity to function as either an application server or as a master application server. In one embodiment, a server106may include an Active Directory. The clients102may also be referred to as client nodes or endpoints. In some embodiments, a client102has the capacity to function as both a client node seeking access to applications on a server and as an application server providing access to hosted applications for other clients102a-102n.

In some embodiments, a client102communicates with a server106. In one embodiment, the client102communicates directly with one of the servers106in a farm38. In another embodiment, the client102executes a program neighborhood application to communicate with a server106in a farm38. In still another embodiment, the server106provides the functionality of a master node. In some embodiments, the client102communicates with the server106in the farm38through a network104. Over the network104, the client102can, for example, request execution of various applications hosted by the servers106a-106nin the farm38and receive output of the results of the application execution for display. In some embodiments, only the master node provides the functionality required to identify and provide address information associated with a server106′ hosting a requested application.

In one embodiment, the server106provides functionality of a web server. In another embodiment, the server106areceives requests from the client102, forwards the requests to a second server106band responds to the request by the client102with a response to the request from the server106b. In still another embodiment, the server106acquires an enumeration of applications available to the client102and address information associated with a server106hosting an application identified by the enumeration of applications. In yet another embodiment, the server106presents the response to the request to the client102using a web interface. In one embodiment, the client102communicates directly with the server106to access the identified application. In another embodiment, the client102receives application output data, such as display data, generated by an execution of the identified application on the server106.

Referring now toFIG. 1B, an embodiment of a network environment deploying multiple appliances200is depicted. A first appliance200may be deployed on a first network104and a second appliance200′ on a second network104′. For example a corporate enterprise may deploy a first appliance200at a branch office and a second appliance200′ at a data center. In another embodiment, the first appliance200and second appliance200′ are deployed on the same network104or network104. For example, a first appliance200may be deployed for a first server farm38, and a second appliance200may be deployed for a second server farm38′. In another example, a first appliance200may be deployed at a first branch office while the second appliance200′ is deployed at a second branch office'. In some embodiments, the first appliance200and second appliance200′ work in cooperation or in conjunction with each other to accelerate network traffic or the delivery of application and data between a client and a server

Referring now toFIG. 1C, another embodiment of a network environment deploying the appliance200with one or more other types of appliances, such as between one or more WAN optimization appliance205,205′ is depicted. For example a first WAN optimization appliance205is shown between networks104and104′ and s second WAN optimization appliance205′ may be deployed between the appliance200and one or more servers106. By way of example, a corporate enterprise may deploy a first WAN optimization appliance205at a branch office and a second WAN optimization appliance205′ at a data center. In some embodiments, the appliance205may be located on network104′. In other embodiments, the appliance205′ may be located on network104. In some embodiments, the appliance205′ may be located on network104′ or network104″. In one embodiment, the appliance205and205′ are on the same network. In another embodiment, the appliance205and205′ are on different networks. In another example, a first WAN optimization appliance205may be deployed for a first server farm38and a second WAN optimization appliance205′ for a second server farm38′

In one embodiment, the appliance205is a device for accelerating, optimizing or otherwise improving the performance, operation, or quality of service of any type and form of network traffic, such as traffic to and/or from a WAN connection. In some embodiments, the appliance205is a performance enhancing proxy. In other embodiments, the appliance205is any type and form of WAN optimization or acceleration device, sometimes also referred to as a WAN optimization controller. In one embodiment, the appliance205is any of the product embodiments referred to as WANScaler manufactured by Citrix Systems, Inc. of Ft. Lauderdale, Fla. In other embodiments, the appliance205includes any of the product embodiments referred to as BIG-IP link controller and WANjet manufactured by F5 Networks, Inc. of Seattle, Wash. In another embodiment, the appliance205includes any of the WX and WXC WAN acceleration device platforms manufactured by Juniper Networks, Inc. of Sunnyvale, Calif. In some embodiments, the appliance205includes any of the steelhead line of WAN optimization appliances manufactured by Riverbed Technology of San Francisco, Calif. In other embodiments, the appliance205includes any of the WAN related devices manufactured by Expand Networks Inc. of Roseland, N.J. In one embodiment, the appliance205includes any of the WAN related appliances manufactured by Packeteer Inc. of Cupertino, Calif., such as the PacketShaper, iShared, and SkyX product embodiments provided by Packeteer. In yet another embodiment, the appliance205includes any WAN related appliances and/or software manufactured by Cisco Systems, Inc. of San Jose, Calif., such as the Cisco Wide Area Network Application Services software and network modules, and Wide Area Network engine appliances.

In one embodiment, the appliance205provides application and data acceleration services for branch-office or remote offices. In one embodiment, the appliance205includes optimization of Wide Area File Services (WAFS). In another embodiment, the appliance205accelerates the delivery of files, such as via the Common Internet File System (CIFS) protocol. In other embodiments, the appliance205provides caching in memory and/or storage to accelerate delivery of applications and data. In one embodiment, the appliance205provides compression of network traffic at any level of the network stack or at any protocol or network layer. In another embodiment, the appliance205provides transport layer protocol optimizations, flow control, performance enhancements or modifications and/or management to accelerate delivery of applications and data over a WAN connection. For example, in one embodiment, the appliance205provides Transport Control Protocol (TCP) optimizations. In other embodiments, the appliance205provides optimizations, flow control, performance enhancements or modifications and/or management for any session or application layer protocol.

In another embodiment, the appliance205encoded any type and form of data or information into custom or standard TCP and/or IP header fields or option fields of network packet to announce presence, functionality or capability to another appliance205′. In another embodiment, an appliance205′ may communicate with another appliance205′ using data encoded in both TCP and/or IP header fields or options. For example, the appliance may use TCP option(s) or IP header fields or options to communicate one or more parameters to be used by the appliances205,205′ in performing functionality, such as WAN acceleration, or for working in conjunction with each other.

In some embodiments, the appliance200preserves any of the information encoded in TCP and/or IP header and/or option fields communicated between appliances205and205′. For example, the appliance200may terminate a transport layer connection traversing the appliance200, such as a transport layer connection from between a client and a server traversing appliances205and205′. In one embodiment, the appliance200identifies and preserves any encoded information in a transport layer packet transmitted by a first appliance205via a first transport layer connection and communicates a transport layer packet with the encoded information to a second appliance205′ via a second transport layer connection.

Referring now toFIG. 1D, a network environment for delivering and/or operating a computing environment on a client102is depicted. In some embodiments, a server106includes an application delivery system190for delivering a computing environment or an application and/or data file to one or more clients102. In brief overview, a client10is in communication with a server106via network104,104′ and appliance200. For example, the client102may reside in a remote office of a company, e.g., a branch office, and the server106may reside at a corporate data center. The client102comprises a client agent120, and a computing environment15. The computing environment15may execute or operate an application that accesses, processes or uses a data file. The computing environment15, application and/or data file may be delivered via the appliance200and/or the server106.

In some embodiments, the appliance200accelerates delivery of a computing environment15, or any portion thereof, to a client102. In one embodiment, the appliance200accelerates the delivery of the computing environment15by the application delivery system190. For example, the embodiments described herein may be used to accelerate delivery of a streaming application and data file processable by the application from a central corporate data center to a remote user location, such as a branch office of the company. In another embodiment, the appliance200accelerates transport layer traffic between a client102and a server106. The appliance200may provide acceleration techniques for accelerating any transport layer payload from a server106to a client102, such as: 1) transport layer connection pooling, 2) transport layer connection multiplexing, 3) transport control protocol buffering, 4) compression and 5) caching. In some embodiments, the appliance200provides load balancing of servers106in responding to requests from clients102. In other embodiments, the appliance200acts as a proxy or access server to provide access to the one or more servers106. In another embodiment, the appliance200provides a secure virtual private network connection from a first network104of the client102to the second network104′ of the server106, such as an SSL VPN connection. It yet other embodiments, the appliance200provides application firewall security, control and management of the connection and communications between a client102and a server106.

In some embodiments, the application delivery management system190provides application delivery techniques to deliver a computing environment to a desktop of a user, remote or otherwise, based on a plurality of execution methods and based on any authentication and authorization policies applied via a policy engine195. With these techniques, a remote user may obtain a computing environment and access to server stored applications and data files from any network connected device100. In one embodiment, the application delivery system190may reside or execute on a server106. In another embodiment, the application delivery system190may reside or execute on a plurality of servers106a-106n. In some embodiments, the application delivery system190may execute in a server farm38. In one embodiment, the server106executing the application delivery system190may also store or provide the application and data file. In another embodiment, a first set of one or more servers106may execute the application delivery system190, and a different server106nmay store or provide the application and data file. In some embodiments, each of the application delivery system190, the application, and data file may reside or be located on different servers. In yet another embodiment, any portion of the application delivery system190may reside, execute or be stored on or distributed to the appliance200, or a plurality of appliances.

The client102may include a computing environment15for executing an application that uses or processes a data file. The client102via networks104,104′ and appliance200may request an application and data file from the server106. In one embodiment, the appliance200may forward a request from the client102to the server106. For example, the client102may not have the application and data file stored or accessible locally. In response to the request, the application delivery system190and/or server106may deliver the application and data file to the client102. For example, in one embodiment, the server106may transmit the application as an application stream to operate in computing environment15on client102.

In some embodiments, the application delivery system190comprises any portion of the Citrix Access Suite™ by Citrix Systems, Inc., such as the MetaFrame or Citrix Presentation Server™ and/or any of the Microsoft® Windows Terminal Services manufactured by the Microsoft Corporation. In one embodiment, the application delivery system190may deliver one or more applications to clients102or users via a remote-display protocol or otherwise via remote-based or server-based computing. In another embodiment, the application delivery system190may deliver one or more applications to clients or users via steaming of the application.

In one embodiment, the application delivery system190includes a policy engine195for controlling and managing the access to, selection of application execution methods and the delivery of applications. In some embodiments, the policy engine195determines the one or more applications a user or client102may access. In another embodiment, the policy engine195determines how the application should be delivered to the user or client102, e.g., the method of execution. In some embodiments, the application delivery system190provides a plurality of delivery techniques from which to select a method of application execution, such as a server-based computing, streaming or delivering the application locally to the client120for local execution.

In one embodiment, a client102requests execution of an application program and the application delivery system190comprising a server106selects a method of executing the application program. In some embodiments, the server106receives credentials from the client102. In another embodiment, the server106receives a request for an enumeration of available applications from the client102. In one embodiment, in response to the request or receipt of credentials, the application delivery system190enumerates a plurality of application programs available to the client102. The application delivery system190receives a request to execute an enumerated application. The application delivery system190selects one of a predetermined number of methods for executing the enumerated application, for example, responsive to a policy of a policy engine. The application delivery system190may select a method of execution of the application enabling the client102to receive application-output data generated by execution of the application program on a server106. The application delivery system190may select a method of execution of the application enabling the local machine10to execute the application program locally after retrieving a plurality of application files comprising the application. In yet another embodiment, the application delivery system190may select a method of execution of the application to stream the application via the network104to the client102.

A client102may execute, operate or otherwise provide an application, which can be any type and/or form of software, program, or executable instructions such as any type and/or form of web browser, web-based client, client-server application, a thin-client computing client, an ActiveX control, or a Java applet, or any other type and/or form of executable instructions capable of executing on client102. In some embodiments, the application may be a server-based or a remote-based application executed on behalf of the client102on a server106. In one embodiments the server106may display output to the client102using any thin-client or remote-display protocol, such as the Independent Computing Architecture (ICA) protocol manufactured by Citrix Systems, Inc. of Ft. Lauderdale, Fla. or the Remote Desktop Protocol (RDP) manufactured by the Microsoft Corporation of Redmond, Wash. The application can use any type of protocol and it can be, for example, an HTTP client, an FTP client, an Oscar client, or a Telnet client. In other embodiments, the application comprises any type of software related to VoIP communications, such as a soft IP telephone. In further embodiments, the application comprises any application related to real-time data communications, such as applications for streaming video and/or audio.

In some embodiments, the server106or a server farm38may be running one or more applications, such as an application providing a thin-client computing or remote display presentation application. In one embodiment, the server106or server farm38executes as an application, any portion of the Citrix Access Suite™ by Citrix Systems, Inc., such as the MetaFrame or Citrix Presentation Server™, and/or any of the Microsoft® Windows Terminal Services manufactured by the Microsoft Corporation. In one embodiment, the application is an ICA client, developed by Citrix Systems, Inc. of Fort Lauderdale, Fla. In other embodiments, the application includes a Remote Desktop (RDP) client, developed by Microsoft Corporation of Redmond, Wash. Also, the server106may run an application, which for example, may be an application server providing email services such as Microsoft Exchange manufactured by the Microsoft Corporation of Redmond, Wash., a web or Internet server, or a desktop sharing server, or a collaboration server. In some embodiments, any of the applications may comprise any type of hosted service or products, such as GoToMeeting™ provided by Citrix Online Division, Inc. of Santa Barbara, Calif., WebEx™ provided by WebEx, Inc. of Santa Clara, Calif., or Microsoft Office Live Meeting provided by Microsoft Corporation of Redmond, Wash.

Still referring toFIG. 1D, an embodiment of the network environment may include a monitoring server106A. The monitoring server106A may include any type and form performance monitoring service198. The performance monitoring service198may include monitoring, measurement and/or management software and/or hardware, including data collection, aggregation, analysis, management and reporting. In one embodiment, the performance monitoring service198includes one or more monitoring agents197. The monitoring agent197includes any software, hardware or combination thereof for performing monitoring, measurement and data collection activities on a device, such as a client102, server106or an appliance200,205. In some embodiments, the monitoring agent197includes any type and form of script, such as Visual Basic script, or Javascript. In one embodiment, the monitoring agent197executes transparently to any application and/or user of the device. In some embodiments, the monitoring agent197is installed and operated unobtrusively to the application or client. In yet another embodiment, the monitoring agent197is installed and operated without any instrumentation for the application or device.

In some embodiments, the monitoring agent197monitors, measures and collects data on a predetermined frequency. In other embodiments, the monitoring agent197monitors, measures and collects data based upon detection of any type and form of event. For example, the monitoring agent197may collect data upon detection of a request for a web page or receipt of an HTTP response. In another example, the monitoring agent197may collect data upon detection of any user input events, such as a mouse click. The monitoring agent197may report or provide any monitored, measured or collected data to the monitoring service198. In one embodiment, the monitoring agent197transmits information to the monitoring service198according to a schedule or a predetermined frequency. In another embodiment, the monitoring agent197transmits information to the monitoring service198upon detection of an event.

In some embodiments, the monitoring service198and/or monitoring agent197performs monitoring and performance measurement of any network resource or network infrastructure element, such as a client, server, server farm, appliance200, appliance205, or network connection. In one embodiment, the monitoring service198and/or monitoring agent197performs monitoring and performance measurement of any transport layer connection, such as a TCP or UDP connection. In another embodiment, the monitoring service198and/or monitoring agent197monitors and measures network latency. In yet one embodiment, the monitoring service198and/or monitoring agent197monitors and measures bandwidth utilization.

In other embodiments, the monitoring service198and/or monitoring agent197monitors and measures end-user response times. In some embodiments, the monitoring service198performs monitoring and performance measurement of an application. In another embodiment, the monitoring service198and/or monitoring agent197performs monitoring and performance measurement of any session or connection to the application. In one embodiment, the monitoring service198and/or monitoring agent197monitors and measures performance of a browser. In another embodiment, the monitoring service198and/or monitoring agent197monitors and measures performance of HTTP based transactions. In some embodiments, the monitoring service198and/or monitoring agent197monitors and measures performance of a Voice over IP (VoIP) application or session. In other embodiments, the monitoring service198and/or monitoring agent197monitors and measures performance of a remote display protocol application, such as an ICA client or RDP client. In yet another embodiment, the monitoring service198and/or monitoring agent197monitors and measures performance of any type and form of streaming media. In still a further embodiment, the monitoring service198and/or monitoring agent197monitors and measures performance of a hosted application or a Software-As-A-Service (SaaS) delivery model.

In some embodiments, the monitoring service198and/or monitoring agent197performs monitoring and performance measurement of one or more transactions, requests or responses related to application. In other embodiments, the monitoring service198and/or monitoring agent197monitors and measures any portion of an application layer stack, such as any .NET or J2EE calls. In one embodiment, the monitoring service198and/or monitoring agent197monitors and measures database or SQL transactions. In yet another embodiment, the monitoring service198and/or monitoring agent197monitors and measures any method, function or application programming interface (API) call.

In one embodiment, the monitoring service198and/or monitoring agent197performs monitoring and performance measurement of a delivery of application and/or data from a server to a client via one or more appliances, such as appliance200and/or appliance205. In some embodiments, the monitoring service198and/or monitoring agent197monitors and measures performance of delivery of a virtualized application. In other embodiments, the monitoring service198and/or monitoring agent197monitors and measures performance of delivery of a streaming application. In another embodiment, the monitoring service198and/or monitoring agent197monitors and measures performance of delivery of a desktop application to a client and/or the execution of the desktop application on the client. In another embodiment, the monitoring service198and/or monitoring agent197monitors and measures performance of a client/server application.

In one embodiment, the monitoring service198and/or monitoring agent197is designed and constructed to provide application performance management for the application delivery system190. For example, the monitoring service198and/or monitoring agent197may monitor, measure and manage the performance of the delivery of applications via the Citrix Presentation Server. In this example, the monitoring service198and/or monitoring agent197monitors individual ICA sessions. The monitoring service198and/or monitoring agent197may measure the total and per session system resource usage, as well as application and networking performance. The monitoring service198and/or monitoring agent197may identify the active servers for a given user and/or user session. In some embodiments, the monitoring service198and/or monitoring agent197monitors back-end connections between the application delivery system190and an application and/or database server. The monitoring service198and/or monitoring agent197may measure network latency, delay and volume per user-session or ICA session.

In some embodiments, the monitoring service198and/or monitoring agent197measures and monitors memory usage for the application delivery system190, such as total memory usage, per user session and/or per process. In other embodiments, the monitoring service198and/or monitoring agent197measures and monitors CPU usage the application delivery system190, such as total CPU usage, per user session and/or per process. In another embodiments, the monitoring service198and/or monitoring agent197measures and monitors the time required to log-in to an application, a server, or the application delivery system, such as Citrix Presentation Server. In one embodiment, the monitoring service198and/or monitoring agent197measures and monitors the duration a user is logged into an application, a server, or the application delivery system190. In some embodiments, the monitoring service198and/or monitoring agent197measures and monitors active and inactive session counts for an application, server or application delivery system session. In yet another embodiment, the monitoring service198and/or monitoring agent197measures and monitors user session latency.

In yet further embodiments, the monitoring service198and/or monitoring agent197measures and monitors measures and monitors any type and form of server metrics. In one embodiment, the monitoring service198and/or monitoring agent197measures and monitors metrics related to system memory, CPU usage, and disk storage. In another embodiment, the monitoring service198and/or monitoring agent197measures and monitors metrics related to page faults, such as page faults per second. In other embodiments, the monitoring service198and/or monitoring agent197measures and monitors round-trip time metrics. In yet another embodiment, the monitoring service198and/or monitoring agent197measures and monitors metrics related to application crashes, errors and/or hangs.

In some embodiments, the monitoring service198and monitoring agent198includes any of the product embodiments referred to as EdgeSight manufactured by Citrix Systems, Inc. of Ft. Lauderdale, Fla. In another embodiment, the performance monitoring service198and/or monitoring agent198includes any portion of the product embodiments referred to as the TrueView product suite manufactured by the Symphoniq Corporation of Palo Alto, California. In one embodiment, the performance monitoring service198and/or monitoring agent198includes any portion of the product embodiments referred to as the TeaLeaf CX product suite manufactured by the TeaLeaf Technology Inc. of San Francisco, Calif. In other embodiments, the performance monitoring service198and/or monitoring agent198includes any portion of the business service management products, such as the BMC Performance Manager and Patrol products, manufactured by BMC Software, Inc. of Houston, Tex.

The client102, server106, and appliance200may be deployed as and/or executed on any type and form of computing device, such as a computer, network device or appliance capable of communicating on any type and form of network and performing the operations described herein.FIGS. 1E and 1Fdepict block diagrams of a computing device100useful for practicing an embodiment of the client102, server106or appliance200. As shown inFIGS. 1E and 1F, each computing device100includes a central processing unit101, and a main memory unit122. As shown inFIG. 1E, a computing device100may include a visual display device124, a keyboard126and/or a pointing device127, such as a mouse. Each computing device100may also include additional optional elements, such as one or more input/output devices130a-130b(generally referred to using reference numeral130), and a cache memory140in communication with the central processing unit101.

The central processing unit101is any logic circuitry that responds to and processes instructions fetched from the main memory unit122. In many embodiments, the central processing unit is provided by a microprocessor unit, such as: those manufactured by Intel Corporation of Mountain View, Calif.; those manufactured by Motorola Corporation of Schaumburg, Ill.; those manufactured by Transmeta Corporation of Santa Clara, Calif.; the RS/6000 processor, those manufactured by International Business Machines of White Plains, N.Y.; or those manufactured by Advanced Micro Devices of Sunnyvale, Calif. The computing device100may be based on any of these processors, or any other processor capable of operating as described herein.

Main memory unit122may be one or more memory chips capable of storing data and allowing any storage location to be directly accessed by the microprocessor101, such as Static random access memory (SRAM), Burst SRAM or SynchBurst SRAM (BSRAM), Dynamic random access memory (DRAM), Fast Page Mode DRAM (FPM DRAM), Enhanced DRAM (EDRAM), Extended Data Output RAM (EDO RAM), Extended Data Output DRAM (EDO DRAM), Burst Extended Data Output DRAM (BEDO DRAM), Enhanced DRAM (EDRAM), synchronous DRAM (SDRAM), JEDEC SRAM, PC100 SDRAM, Double Data Rate SDRAM (DDR SDRAM), Enhanced SDRAM (ESDRAM), SyncLink DRAM (SLDRAM), Direct Rambus DRAM (DRDRAM), or Ferroelectric RAM (FRAM). The main memory122may be based on any of the above described memory chips, or any other available memory chips capable of operating as described herein. In the embodiment shown inFIG. 1E, the processor101communicates with main memory122via a system bus150(described in more detail below).FIG. 1Edepicts an embodiment of a computing device100in which the processor communicates directly with main memory122via a memory port103. For example, inFIG. 1Fthe main memory122may be DRDRAM.

FIG. 1Fdepicts an embodiment in which the main processor101communicates directly with cache memory140via a secondary bus, sometimes referred to as a backside bus. In other embodiments, the main processor101communicates with cache memory140using the system bus150. Cache memory140typically has a faster response time than main memory122and is typically provided by SRAM, BSRAM, or EDRAM. In the embodiment shown inFIG. 1E, the processor101communicates with various I/O devices130via a local system bus150. Various busses may be used to connect the central processing unit101to any of the I/O devices130, including a VESA VL bus, an ISA bus, an EISA bus, a MicroChannel Architecture (MCA) bus, a PCI bus, a PCI-X bus, a PCI-Express bus, or a NuBus. For embodiments in which the I/O device is a video display124, the processor101may use an Advanced Graphics Port (AGP) to communicate with the display124.FIG. 1Fdepicts an embodiment of a computer100in which the main processor101communicates directly with I/O device130via HyperTransport, Rapid I/O, or InfiniBand.FIG. 1Falso depicts an embodiment in which local busses and direct communication are mixed: the processor101communicates with I/O device130using a local interconnect bus while communicating with I/O device130directly.

The computing device100may support any suitable installation device116, such as a floppy disk drive for receiving floppy disks such as 3.5-inch, 5.25-inch disks or ZIP disks, a CD-ROM drive, a CD-R/RW drive, a DVD-ROM drive, tape drives of various formats, USB device, hard-drive or any other device suitable for installing software and programs such as any client agent120, or portion thereof. The computing device100may further comprise a storage device128, such as one or more hard disk drives or redundant arrays of independent disks, for storing an operating system and other related software, and for storing application software programs such as any program related to the client agent120. Optionally, any of the installation devices116could also be used as the storage device128. Additionally, the operating system and the software can be run from a bootable medium, for example, a bootable CD, such as KNOPPIX®, a bootable CD for GNU/Linux that is available as a GNU/Linux distribution from knoppix.net.

Furthermore, the computing device100may include a network interface118to interface to a Local Area Network (LAN), Wide Area Network (WAN) or the Internet through a variety of connections including, but not limited to, standard telephone lines, LAN or WAN links (e.g., 802.11, T1, T3, 56 kb, X.25), broadband connections (e.g., ISDN, Frame Relay, ATM), wireless connections, or some combination of any or all of the above. The network interface118may comprise a built-in network adapter, network interface card, PCMCIA network card, card bus network adapter, wireless network adapter, USB network adapter, modem or any other device suitable for interfacing the computing device100to any type of network capable of communication and performing the operations described herein. A wide variety of I/O devices130a-130nmay be present in the computing device100. Input devices include keyboards, mice, trackpads, trackballs, microphones, and drawing tablets. Output devices include video displays, speakers, inkjet printers, laser printers, and dye-sublimation printers. The I/O devices130may be controlled by an I/O controller123as shown inFIG. 1E. The I/O controller may control one or more I/O devices such as a keyboard126and a pointing device127, e.g., a mouse or optical pen. Furthermore, an I/O device may also provide storage128and/or an installation medium116for the computing device100. In still other embodiments, the computing device100may provide USB connections to receive handheld USB storage devices such as the USB Flash Drive line of devices manufactured by Twintech Industry, Inc. of Los Alamitos, Calif.

In some embodiments, the computing device100may comprise or be connected to multiple display devices124a-124n, which each may be of the same or different type and/or form. As such, any of the I/O devices130a-130nand/or the I/O controller123may comprise any type and/or form of suitable hardware, software, or combination of hardware and software to support, enable or provide for the connection and use of multiple display devices124a-124nby the computing device100. For example, the computing device100may include any type and/or form of video adapter, video card, driver, and/or library to interface, communicate, connect or otherwise use the display devices124a-124n. In one embodiment, a video adapter may comprise multiple connectors to interface to multiple display devices124a-124n. In other embodiments, the computing device100may include multiple video adapters, with each video adapter connected to one or more of the display devices124a-124n. In some embodiments, any portion of the operating system of the computing device100may be configured for using multiple displays124a-124n. In other embodiments, one or more of the display devices124a-124nmay be provided by one or more other computing devices, such as computing devices100aand100bconnected to the computing device100, for example, via a network. These embodiments may include any type of software designed and constructed to use another computer's display device as a second display device124afor the computing device100. One ordinarily skilled in the art will recognize and appreciate the various ways and embodiments that a computing device100may be configured to have multiple display devices124a-124n.

In other embodiments, the computing device100may have different processors, operating systems, and input devices consistent with the device. For example, in one embodiment the computer100is a Treo 180, 270, 1060, 600 or 650 smart phone manufactured by Palm, Inc. In this embodiment, the Treo smart phone is operated under the control of the PalmOS operating system and includes a stylus input device as well as a five-way navigator device. Moreover, the computing device100can be any workstation, desktop computer, laptop or notebook computer, server, handheld computer, mobile telephone, any other computer, or other form of computing or telecommunications device that is capable of communication and that has sufficient processor power and memory capacity to perform the operations described herein.

As shown inFIG. 1G, the computing device100may comprise multiple processors and may provide functionality for simultaneous execution of instructions or for simultaneous execution of one instruction on more than one piece of data. In some embodiments, the computing device100may comprise a parallel processor with one or more cores. In one of these embodiments, the computing device100is a shared memory parallel device, with multiple processors and/or multiple processor cores, accessing all available memory as a single global address space. In another of these embodiments, the computing device100is a distributed memory parallel device with multiple processors each accessing local memory only. In still another of these embodiments, the computing device100has both some memory which is shared and some memory which can only be accessed by particular processors or subsets of processors. In still even another of these embodiments, the computing device100, such as a multi-core microprocessor, combines two or more independent processors into a single package, often a single integrated circuit (IC). In yet another of these embodiments, the computing device100includes a chip having a CELL BROADBAND ENGINE architecture and including a Power processor element and a plurality of synergistic processing elements, the Power processor element and the plurality of synergistic processing elements linked together by an internal high speed bus, which may be referred to as an element interconnect bus.

In some embodiments, the processors provide functionality for execution of a single instruction simultaneously on multiple pieces of data (SIMD). In other embodiments, the processors provide functionality for execution of multiple instructions simultaneously on multiple pieces of data (MIMD). In still other embodiments, the processor may use any combination of SIMD and MIMD cores in a single device.

In some embodiments, the computing device100may comprise a graphics processing unit. In one of these embodiments, depicted inFIG. 1H, the computing device100includes at least one central processing unit101and at least one graphics processing unit. In another of these embodiments, the computing device100includes at least one parallel processing unit and at least one graphics processing unit. In still another of these embodiments, the computing device100includes a plurality of processing units of any type, one of the plurality of processing units comprising a graphics processing unit.

In some embodiments, a first computing device100aexecutes an application on behalf of a user of a client computing device100b. In other embodiments, a computing device100aexecutes a virtual machine, which provides an execution session within which applications execute on behalf of a user or a client computing devices100b. In one of these embodiments, the execution session is a hosted desktop session. In another of these embodiments, the computing device100executes a terminal services session. The terminal services session may provide a hosted desktop environment. In still another of these embodiments, the execution session provides access to a computing environment, which may comprise one or more of: an application, a plurality of applications, a desktop application, and a desktop session in which one or more applications may execute.

B. Appliance Architecture

FIG. 2Aillustrates an example embodiment of the appliance200. The architecture of the appliance200inFIG. 2Ais provided by way of illustration only and is not intended to be limiting. As shown inFIG. 2, appliance200comprises a hardware layer206and a software layer divided into a user space202and a kernel space204.

Hardware layer206provides the hardware elements upon which programs and services within kernel space204and user space202are executed. Hardware layer206also provides the structures and elements which allow programs and services within kernel space204and user space202to communicate data both internally and externally with respect to appliance200. As shown inFIG. 2, the hardware layer206includes a processing unit262for executing software programs and services, a memory264for storing software and data, network ports266for transmitting and receiving data over a network, and an encryption processor260for performing functions related to Secure Sockets Layer processing of data transmitted and received over the network. In some embodiments, the central processing unit262may perform the functions of the encryption processor260in a single processor.

Additionally, the hardware layer206may comprise multiple processors for each of the processing unit262and the encryption processor260. The processor262may include any of the processors101described above in connection withFIGS. 1E and 1F. For example, in one embodiment, the appliance200comprises a first processor262and a second processor262′. In other embodiments, the processor262or262′ comprises a multi-core processor.

Although the hardware layer206of appliance200is generally illustrated with an encryption processor260, processor260may be a processor for performing functions related to any encryption protocol, such as the Secure Socket Layer (SSL) or Transport Layer Security (TLS) protocol. In some embodiments, the processor260may be a general purpose processor (GPP), and in further embodiments, may have executable instructions for performing processing of any security related protocol.

Although the hardware layer206of appliance200is illustrated with certain elements inFIG. 2, the hardware portions or components of appliance200may comprise any type and form of elements, hardware or software, of a computing device, such as the computing device100illustrated and discussed herein in conjunction withFIGS. 1E and 1F. In some embodiments, the appliance200may comprise a server, gateway, router, switch, bridge or other type of computing or network device, and have any hardware and/or software elements associated therewith.

The operating system of appliance200allocates, manages, or otherwise segregates the available system memory into kernel space204and user space204. In example software architecture200, the operating system may be any type and/or form of Unix operating system although the invention is not so limited. As such, the appliance200can be running any operating system such as any of the versions of the Microsoft® Windows operating systems, the different releases of the Unix and Linux operating systems, any version of the Mac OS® for Macintosh computers, any embedded operating system, any network operating system, any real-time operating system, any open source operating system, any proprietary operating system, any operating systems for mobile computing devices or network devices, or any other operating system capable of running on the appliance200and performing the operations described herein.

The kernel space204is reserved for running the kernel230, including any device drivers, kernel extensions or other kernel related software. As known to those skilled in the art, the kernel230is the core of the operating system, and provides access, control, and management of resources and hardware-related elements of the application104. In accordance with an embodiment of the appliance200, the kernel space204also includes a number of network services or processes working in conjunction with a cache manager232, sometimes also referred to as the integrated cache, the benefits of which are described in detail further herein. Additionally, the embodiment of the kernel230will depend on the embodiment of the operating system installed, configured, or otherwise used by the device200.

In one embodiment, the device200comprises one network stack267, such as a TCP/IP based stack, for communicating with the client102and/or the server106. In one embodiment, the network stack267is used to communicate with a first network, such as network108, and a second network110. In some embodiments, the device200terminates a first transport layer connection, such as a TCP connection of a client102, and establishes a second transport layer connection to a server106for use by the client102, e.g., the second transport layer connection is terminated at the appliance200and the server106. The first and second transport layer connections may be established via a single network stack267. In other embodiments, the device200may comprise multiple network stacks, for example267and267′, and the first transport layer connection may be established or terminated at one network stack267, and the second transport layer connection on the second network stack267′. For example, one network stack may be for receiving and transmitting network packet on a first network, and another network stack for receiving and transmitting network packets on a second network. In one embodiment, the network stack267comprises a buffer243for queuing one or more network packets for transmission by the appliance200.

As shown inFIG. 2, the kernel space204includes the cache manager232, a high-speed layer2-7integrated packet engine240, an encryption engine234, a policy engine236and multi-protocol compression logic238. Running these components or processes232,240,234,236and238in kernel space204or kernel mode instead of the user space202improves the performance of each of these components, alone and in combination. Kernel operation means that these components or processes232,240,234,236and238run in the core address space of the operating system of the device200. For example, running the encryption engine234in kernel mode improves encryption performance by moving encryption and decryption operations to the kernel, thereby reducing the number of transitions between the memory space or a kernel thread in kernel mode and the memory space or a thread in user mode. For example, data obtained in kernel mode may not need to be passed or copied to a process or thread running in user mode, such as from a kernel level data structure to a user level data structure. In another aspect, the number of context switches between kernel mode and user mode are also reduced. Additionally, synchronization of and communications between any of the components or processes232,240,235,236and238can be performed more efficiently in the kernel space204.

In some embodiments, any portion of the components232,240,234,236and238may run or operate in the kernel space204, while other portions of these components232,240,234,236and238may run or operate in user space202. In one embodiment, the appliance200uses a kernel-level data structure providing access to any portion of one or more network packets, for example, a network packet comprising a request from a client102or a response from a server106. In some embodiments, the kernel-level data structure may be obtained by the packet engine240via a transport layer driver interface or filter to the network stack267. The kernel-level data structure may comprise any interface and/or data accessible via the kernel space204related to the network stack267, network traffic or packets received or transmitted by the network stack267. In other embodiments, the kernel-level data structure may be used by any of the components or processes232,240,234,236and238to perform the desired operation of the component or process. In one embodiment, a component232,240,234,236and238is running in kernel mode204when using the kernel-level data structure, while in another embodiment, the component232,240,234,236and238is running in user mode when using the kernel-level data structure. In some embodiments, the kernel-level data structure may be copied or passed to a second kernel-level data structure, or any desired user-level data structure.

The cache manager232may comprise software, hardware or any combination of software and hardware to provide cache access, control and management of any type and form of content, such as objects or dynamically generated objects served by the originating servers106. The data, objects or content processed and stored by the cache manager232may comprise data in any format, such as a markup language, or communicated via any protocol. In some embodiments, the cache manager232duplicates original data stored elsewhere or data previously computed, generated or transmitted, in which the original data may require longer access time to fetch, compute or otherwise obtain relative to reading a cache memory element. Once the data is stored in the cache memory element, future use can be made by accessing the cached copy rather than refetching or recomputing the original data, thereby reducing the access time. In some embodiments, the cache memory element may comprise a data object in memory264of device200. In other embodiments, the cache memory element may comprise memory having a faster access time than memory264. In another embodiment, the cache memory element may comprise any type and form of storage element of the device200, such as a portion of a hard disk. In some embodiments, the processing unit262may provide cache memory for use by the cache manager232. In yet further embodiments, the cache manager232may use any portion and combination of memory, storage, or the processing unit for caching data, objects, and other content.

Furthermore, the cache manager232includes any logic, functions, rules, or operations to perform any embodiments of the techniques of the appliance200described herein. For example, the cache manager232includes logic or functionality to invalidate objects based on the expiration of an invalidation time period or upon receipt of an invalidation command from a client102or server106. In some embodiments, the cache manager232may operate as a program, service, process or task executing in the kernel space204, and in other embodiments, in the user space202. In one embodiment, a first portion of the cache manager232executes in the user space202while a second portion executes in the kernel space204. In some embodiments, the cache manager232can comprise any type of general purpose processor (GPP), or any other type of integrated circuit, such as a Field Programmable Gate Array (FPGA), Programmable Logic Device (PLD), or Application Specific Integrated Circuit (ASIC).

The policy engine236may include, for example, an intelligent statistical engine or other programmable application(s). In one embodiment, the policy engine236provides a configuration mechanism to allow a user to identify, specify, define or configure a caching policy. Policy engine236, in some embodiments, also has access to memory to support data structures such as lookup tables or hash tables to enable user-selected caching policy decisions. In other embodiments, the policy engine236may comprise any logic, rules, functions or operations to determine and provide access, control and management of objects, data or content being cached by the appliance200in addition to access, control and management of security, network traffic, network access, compression or any other function or operation performed by the appliance200. Further examples of specific caching policies are further described herein.

The encryption engine234comprises any logic, business rules, functions or operations for handling the processing of any security related protocol, such as SSL or TLS, or any function related thereto. For example, the encryption engine234encrypts and decrypts network packets, or any portion thereof, communicated via the appliance200. The encryption engine234may also setup or establish SSL or TLS connections on behalf of the client102a-102n, server106a-106n, or appliance200. As such, the encryption engine234provides offloading and acceleration of SSL processing. In one embodiment, the encryption engine234uses a tunneling protocol to provide a virtual private network between a client102a-102nand a server106a-106n. In some embodiments, the encryption engine234is in communication with the Encryption processor260. In other embodiments, the encryption engine234comprises executable instructions running on the Encryption processor260.

The multi-protocol compression engine238comprises any logic, business rules, function or operations for compressing one or more protocols of a network packet, such as any of the protocols used by the network stack267of the device200. In one embodiment, multi-protocol compression engine238compresses bi-directionally between clients102a-102nand servers106a-106nany TCP/IP based protocol, including Messaging Application Programming Interface (MAPI) (email), File Transfer Protocol (FTP), HyperText Transfer Protocol (HTTP), Common Internet File System (CIFS) protocol (file transfer), Independent Computing Architecture (ICA) protocol, Remote Desktop Protocol (RDP), Wireless Application Protocol (WAP), Mobile IP protocol, and Voice Over IP (VoIP) protocol. In other embodiments, multi-protocol compression engine238provides compression of Hypertext Markup Language (HTML) based protocols and in some embodiments, provides compression of any markup languages, such as the Extensible Markup Language (XML). In one embodiment, the multi-protocol compression engine238provides compression of any high-performance protocol, such as any protocol designed for appliance200to appliance200communications. In another embodiment, the multi-protocol compression engine238compresses any payload of or any communication using a modified transport control protocol, such as Transaction TCP (T/TCP), TCP with selection acknowledgements (TCP-SACK), TCP with large windows (TCP-LW), a congestion prediction protocol such as the TCP-Vegas protocol, and a TCP spoofing protocol.

As such, the multi-protocol compression engine238accelerates performance for users accessing applications via desktop clients, e.g., Microsoft Outlook and non-Web thin clients, such as any client launched by popular enterprise applications like Oracle, SAP and Siebel, and even mobile clients, such as the Pocket PC. In some embodiments, the multi-protocol compression engine238by executing in the kernel mode204and integrating with packet processing engine240accessing the network stack267is able to compress any of the protocols carried by the TCP/IP protocol, such as any application layer protocol.

High speed layer2-7integrated packet engine240, also generally referred to as a packet processing engine or packet engine, is responsible for managing the kernel-level processing of packets received and transmitted by appliance200via network ports266. The high speed layer2-7integrated packet engine240may comprise a buffer for queuing one or more network packets during processing, such as for receipt of a network packet or transmission of a network packet. Additionally, the high speed layer2-7integrated packet engine240is in communication with one or more network stacks267to send and receive network packets via network ports266. The high speed layer2-7integrated packet engine240works in conjunction with encryption engine234, cache manager232, policy engine236and multi-protocol compression logic238. In particular, encryption engine234is configured to perform SSL processing of packets, policy engine236is configured to perform functions related to traffic management such as request-level content switching and request-level cache redirection, and multi-protocol compression logic238is configured to perform functions related to compression and decompression of data.

The high speed layer2-7integrated packet engine240includes a packet processing timer242. In one embodiment, the packet processing timer242provides one or more time intervals to trigger the processing of incoming, i.e., received, or outgoing, i.e., transmitted, network packets. In some embodiments, the high speed layer2-7integrated packet engine240processes network packets responsive to the timer242. The packet processing timer242provides any type and form of signal to the packet engine240to notify, trigger, or communicate a time related event, interval or occurrence. In many embodiments, the packet processing timer242operates in the order of milliseconds, such as for example 100 ms, 50 ms or 25 ms. For example, in some embodiments, the packet processing timer242provides time intervals or otherwise causes a network packet to be processed by the high speed layer2-7integrated packet engine240at a 10 ms time interval, while in other embodiments, at a 5 ms time interval, and still yet in further embodiments, as short as a 3, 2, or 1 ms time interval. The high speed layer2-7integrated packet engine240may be interfaced, integrated or in communication with the encryption engine234, cache manager232, policy engine236and multi-protocol compression engine238during operation. As such, any of the logic, functions, or operations of the encryption engine234, cache manager232, policy engine236and multi-protocol compression logic238may be performed responsive to the packet processing timer242and/or the packet engine240. Therefore, any of the logic, functions, or operations of the encryption engine234, cache manager232, policy engine236and multi-protocol compression logic238may be performed at the granularity of time intervals provided via the packet processing timer242, for example, at a time interval of less than or equal to 10 ms. For example, in one embodiment, the cache manager232may perform invalidation of any cached objects responsive to the high speed layer2-7integrated packet engine240and/or the packet processing timer242. In another embodiment, the expiry or invalidation time of a cached object can be set to the same order of granularity as the time interval of the packet processing timer242, such as at every 10 ms.

In contrast to kernel space204, user space202is the memory area or portion of the operating system used by user mode applications or programs otherwise running in user mode. A user mode application may not access kernel space204directly and uses service calls in order to access kernel services. As shown inFIG. 2, user space202of appliance200includes a graphical user interface (GUI)210, a command line interface (CLI)212, shell services214, health monitoring program216, and daemon services218. GUI210and CLI212provide a means by which a system administrator or other user can interact with and control the operation of appliance200, such as via the operating system of the appliance200. The GUI210or CLI212can comprise code running in user space202or kernel space204. The GUI210may be any type and form of graphical user interface and may be presented via text, graphical or otherwise, by any type of program or application, such as a browser. The CLI212may be any type and form of command line or text-based interface, such as a command line provided by the operating system. For example, the CLI212may comprise a shell, which is a tool to enable users to interact with the operating system. In some embodiments, the CLI212may be provided via a bash, csh, tcsh, or ksh type shell. The shell services214comprises the programs, services, tasks, processes or executable instructions to support interaction with the appliance200or operating system by a user via the GUI210and/or CLI212.

Health monitoring program216is used to monitor, check, report and ensure that network systems are functioning properly and that users are receiving requested content over a network. Health monitoring program216comprises one or more programs, services, tasks, processes or executable instructions to provide logic, rules, functions or operations for monitoring any activity of the appliance200. In some embodiments, the health monitoring program216intercepts and inspects any network traffic passed via the appliance200. In other embodiments, the health monitoring program216interfaces by any suitable means and/or mechanisms with one or more of the following: the encryption engine234, cache manager232, policy engine236, multi-protocol compression logic238, packet engine240, daemon services218, and shell services214. As such, the health monitoring program216may call any application programming interface (API) to determine a state, status, or health of any portion of the appliance200. For example, the health monitoring program216may ping or send a status inquiry on a periodic basis to check if a program, process, service or task is active and currently running. In another example, the health monitoring program216may check any status, error or history logs provided by any program, process, service or task to determine any condition, status or error with any portion of the appliance200.

Daemon services218are programs that run continuously or in the background and handle periodic service requests received by appliance200. In some embodiments, a daemon service may forward the requests to other programs or processes, such as another daemon service218as appropriate. As known to those skilled in the art, a daemon service218may run unattended to perform continuous or periodic system wide functions, such as network control, or to perform any desired task. In some embodiments, one or more daemon services218run in the user space202, while in other embodiments, one or more daemon services218run in the kernel space.

Referring now toFIG. 2B, another embodiment of the appliance200is depicted. In brief overview, the appliance200provides one or more of the following services, functionality or operations: SSL VPN connectivity280, switching/load balancing284, Domain Name Service resolution286, acceleration288and an application firewall290for communications between one or more clients102and one or more servers106. Each of the servers106may provide one or more network related services270a-270n(referred to as services270). For example, a server106may provide an http service270. The appliance200comprises one or more virtual servers or virtual internet protocol servers, referred to as a vServer, VIP server, or just VIP275a-275n(also referred herein as vServer275). The vServer275receives, intercepts or otherwise processes communications between a client102and a server106in accordance with the configuration and operations of the appliance200.

The vServer275may comprise software, hardware or any combination of software and hardware. The vServer275may comprise any type and form of program, service, task, process or executable instructions operating in user mode202, kernel mode204or any combination thereof in the appliance200. The vServer275includes any logic, functions, rules, or operations to perform any embodiments of the techniques described herein, such as SSL VPN280, switching/load balancing284, Domain Name Service resolution286, acceleration288and an application firewall290. In some embodiments, the vServer275establishes a connection to a service270of a server106. The service275may comprise any program, application, process, task or set of executable instructions capable of connecting to and communicating to the appliance200, client102or vServer275. For example, the service275may comprise a web server, http server, ftp, email or database server. In some embodiments, the service270is a daemon process or network driver for listening, receiving and/or sending communications for an application, such as email, database or an enterprise application. In some embodiments, the service270may communicate on a specific IP address, or IP address and port.

In some embodiments, the vServer275applies one or more policies of the policy engine236to network communications between the client102and server106. In one embodiment, the policies are associated with a vServer275. In another embodiment, the policies are based on a user, or a group of users. In yet another embodiment, a policy is global and applies to one or more vServers275a-275n, and any user or group of users communicating via the appliance200. In some embodiments, the policies of the policy engine have conditions upon which the policy is applied based on any content of the communication, such as internet protocol address, port, protocol type, header or fields in a packet, or the context of the communication, such as user, group of the user, vServer275, transport layer connection, and/or identification or attributes of the client102or server106.

In other embodiments, the appliance200communicates or interfaces with the policy engine236to determine authentication and/or authorization of a remote user or a remote client102to access the computing environment15, application, and/or data file from a server106. In another embodiment, the appliance200communicates or interfaces with the policy engine236to determine authentication and/or authorization of a remote user or a remote client102to have the application delivery system190deliver one or more of the computing environment15, application, and/or data file. In yet another embodiment, the appliance200establishes a VPN or SSL VPN connection based on the policy engine's236authentication and/or authorization of a remote user or a remote client102In one embodiment, the appliance200controls the flow of network traffic and communication sessions based on policies of the policy engine236. For example, the appliance200may control the access to a computing environment15, application or data file based on the policy engine236.

In some embodiments, the vServer275establishes a transport layer connection, such as a TCP or UDP connection with a client102via the client agent120. In one embodiment, the vServer275listens for and receives communications from the client102. In other embodiments, the vServer275establishes a transport layer connection, such as a TCP or UDP connection with a client server106. In one embodiment, the vServer275establishes the transport layer connection to an internet protocol address and port of a server270running on the server106. In another embodiment, the vServer275associates a first transport layer connection to a client102with a second transport layer connection to the server106. In some embodiments, a vServer275establishes a pool of transport layer connections to a server106and multiplexes client requests via the pooled transport layer connections.

In some embodiments, the appliance200provides a SSL VPN connection280between a client102and a server106. For example, a client102on a first network102requests to establish a connection to a server106on a second network104′. In some embodiments, the second network104′ is not routable from the first network104. In other embodiments, the client102is on a public network104and the server106is on a private network104′, such as a corporate network. In one embodiment, the client agent120intercepts communications of the client102on the first network104, encrypts the communications, and transmits the communications via a first transport layer connection to the appliance200. The appliance200associates the first transport layer connection on the first network104to a second transport layer connection to the server106on the second network104. The appliance200receives the intercepted communication from the client agent102, decrypts the communications, and transmits the communication to the server106on the second network104via the second transport layer connection. The second transport layer connection may be a pooled transport layer connection. As such, the appliance200provides an end-to-end secure transport layer connection for the client102between the two networks104,104′.

In one embodiment, the appliance200hosts an intranet internet protocol or intranetIP282address of the client102on the virtual private network104. The client102has a local network identifier, such as an internet protocol (IP) address and/or host name on the first network104. When connected to the second network104′ via the appliance200, the appliance200establishes, assigns or otherwise provides an IntranetIP, which is network identifier, such as IP address and/or host name, for the client102on the second network104′. The appliance200listens for and receives on the second or private network104′ for any communications directed towards the client102using the client's established IntranetIP282. In one embodiment, the appliance200acts as or on behalf of the client102on the second private network104. For example, in another embodiment, a vServer275listens for and responds to communications to the IntranetIP282of the client102. In some embodiments, if a computing device100on the second network104′ transmits a request, the appliance200processes the request as if it were the client102. For example, the appliance200may respond to a ping to the client's IntranetIP282. In another example, the appliance may establish a connection, such as a TCP or UDP connection, with computing device100on the second network104requesting a connection with the client's IntranetIP282.

In some embodiments, the appliance200provides one or more of the following acceleration techniques288to communications between the client102and server106: 1) compression; 2) decompression; 3) Transmission Control Protocol pooling; 4) Transmission Control Protocol multiplexing; 5) Transmission Control Protocol buffering; and 6) caching. In one embodiment, the appliance200relieves servers106of much of the processing load caused by repeatedly opening and closing transport layers connections to clients102by opening one or more transport layer connections with each server106and maintaining these connections to allow repeated data accesses by clients via the Internet. This technique is referred to herein as “connection pooling”.

In some embodiments, in order to seamlessly splice communications from a client102to a server106via a pooled transport layer connection, the appliance200translates or multiplexes communications by modifying sequence number and acknowledgment numbers at the transport layer protocol level. This is referred to as “connection multiplexing”. In some embodiments, no application layer protocol interaction is required. For example, in the case of an in-bound packet (that is, a packet received from a client102), the source network address of the packet is changed to that of an output port of appliance200, and the destination network address is changed to that of the intended server. In the case of an outbound packet (that is, one received from a server106), the source network address is changed from that of the server106to that of an output port of appliance200and the destination address is changed from that of appliance200to that of the requesting client102. The sequence numbers and acknowledgment numbers of the packet are also translated to sequence numbers and acknowledgement expected by the client102on the appliance's200transport layer connection to the client102. In some embodiments, the packet checksum of the transport layer protocol is recalculated to account for these translations.

In another embodiment, the appliance200provides switching or load-balancing functionality284for communications between the client102and server106. In some embodiments, the appliance200distributes traffic and directs client requests to a server106based on layer4or application-layer request data. In one embodiment, although the network layer or layer2of the network packet identifies a destination server106, the appliance200determines the server106to distribute the network packet by application information and data carried as payload of the transport layer packet. In one embodiment, the health monitoring programs216of the appliance200monitor the health of servers to determine the server106for which to distribute a client's request. In some embodiments, if the appliance200detects a server106is not available or has a load over a predetermined threshold, the appliance200can direct or distribute client requests to another server106.

In some embodiments, the appliance200acts as a Domain Name Service (DNS) resolver or otherwise provides resolution of a DNS request from clients102. In some embodiments, the appliance intercepts' a DNS request transmitted by the client102. In one embodiment, the appliance200responds to a client's DNS request with an IP address of or hosted by the appliance200. In this embodiment, the client102transmits network communication for the domain name to the appliance200. In another embodiment, the appliance200responds to a client's DNS request with an IP address of or hosted by a second appliance200′. In some embodiments, the appliance200responds to a client's DNS request with an IP address of a server106determined by the appliance200.

In yet another embodiment, the appliance200provides application firewall functionality290for communications between the client102and server106. In one embodiment, the policy engine236provides rules for detecting and blocking illegitimate requests. In some embodiments, the application firewall290protects against denial of service (DoS) attacks. In other embodiments, the appliance inspects the content of intercepted requests to identify and block application-based attacks. In some embodiments, the rules/policy engine236comprises one or more application firewall or security control policies for providing protections against various classes and types of web or Internet based vulnerabilities, such as one or more of the following: 1) buffer overflow, 2) CGI-BIN parameter manipulation, 3) form/hidden field manipulation, 4) forceful browsing, 5) cookie or session poisoning, 6) broken access control list (ACLs) or weak passwords, 7) cross-site scripting (XSS), 8) command injection, 9) SQL injection, 10) error triggering sensitive information leak, 11) insecure use of cryptography, 12) server misconfiguration, 13) back doors and debug options, 14) website defacement, 15) platform or operating systems vulnerabilities, and 16) zero-day exploits. In an embodiment, the application firewall290provides HTML form field protection in the form of inspecting or analyzing the network communication for one or more of the following: 1) required fields are returned, 2) no added field allowed, 3) read-only and hidden field enforcement, 4) drop-down list and radio button field conformance, and 5) form-field max-length enforcement. In some embodiments, the application firewall290ensures cookies are not modified. In other embodiments, the application firewall290protects against forceful browsing by enforcing legal URLs.

In still yet other embodiments, the application firewall290protects any confidential information contained in the network communication. The application firewall290may inspect or analyze any network communication in accordance with the rules or polices of the engine236to identify any confidential information in any field of the network packet. In some embodiments, the application firewall290identifies in the network communication one or more occurrences of a credit card number, password, social security number, name, patient code, contact information, and age. The encoded portion of the network communication may comprise these occurrences or the confidential information. Based on these occurrences, in one embodiment, the application firewall290may take a policy action on the network communication, such as prevent transmission of the network communication. In another embodiment, the application firewall290may rewrite, remove or otherwise mask such identified occurrence or confidential information.

Still referring toFIG. 2B, the appliance200may include a performance monitoring agent197as discussed above in conjunction withFIG. 1D. In one embodiment, the appliance200receives the monitoring agent197from the monitoring service198or monitoring server106as depicted inFIG. 1D. In some embodiments, the appliance200stores the monitoring agent197in storage, such as disk, for delivery to any client or server in communication with the appliance200. For example, in one embodiment, the appliance200transmits the monitoring agent197to a client upon receiving a request to establish a transport layer connection. In other embodiments, the appliance200transmits the monitoring agent197upon establishing the transport layer connection with the client102. In another embodiment, the appliance200transmits the monitoring agent197to the client upon intercepting or detecting a request for a web page. In yet another embodiment, the appliance200transmits the monitoring agent197to a client or a server in response to a request from the monitoring server198. In one embodiment, the appliance200transmits the monitoring agent197to a second appliance200′ or appliance205.

In other embodiments, the appliance200executes the monitoring agent197. In one embodiment, the monitoring agent197measures and monitors the performance of any application, program, process, service, task or thread executing on the appliance200. For example, the monitoring agent197may monitor and measure performance and operation of vServers275A-275N. In another embodiment, the monitoring agent197measures and monitors the performance of any transport layer connections of the appliance200. In some embodiments, the monitoring agent197measures and monitors the performance of any user sessions traversing the appliance200. In one embodiment, the monitoring agent197measures and monitors the performance of any virtual private network connections and/or sessions traversing the appliance200, such an SSL VPN session. In still further embodiments, the monitoring agent197measures and monitors the memory, CPU and disk usage and performance of the appliance200. In yet another embodiment, the monitoring agent197measures and monitors the performance of any acceleration technique288performed by the appliance200, such as SSL offloading, connection pooling and multiplexing, caching, and compression. In some embodiments, the monitoring agent197measures and monitors the performance of any load balancing and/or content switching284performed by the appliance200. In other embodiments, the monitoring agent197measures and monitors the performance of application firewall290protection and processing performed by the appliance200.

C. Client Agent

Referring now toFIG. 3, an embodiment of the client agent120is depicted. The client102includes a client agent120for establishing and exchanging communications with the appliance200and/or server106via a network104. In brief overview, the client102operates on computing device100having an operating system with a kernel mode302and a user mode303, and a network stack310with one or more layers310a-310b. The client102may have installed and/or execute one or more applications. In some embodiments, one or more applications may communicate via the network stack310to a network104. One of the applications, such as a web browser, may also include a first program322. For example, the first program322may be used in some embodiments to install and/or execute the client agent120, or any portion thereof. The client agent120includes an interception mechanism, or interceptor350, for intercepting network communications from the network stack310from the one or more applications.

The network stack310of the client102may comprise any type and form of software, or hardware, or any combinations thereof, for providing connectivity to and communications with a network. In one embodiment, the network stack310comprises a software implementation for a network protocol suite. The network stack310may comprise one or more network layers, such as any networks layers of the Open Systems Interconnection (OSI) communications model as those skilled in the art recognize and appreciate. As such, the network stack310may comprise any type and form of protocols for any of the following layers of the OSI model: 1) physical link layer, 2) data link layer, 3) network layer, 4) transport layer, 5) session layer, 6) presentation layer, and 7) application layer. In one embodiment, the network stack310may comprise a transport control protocol (TCP) over the network layer protocol of the internet protocol (IP), generally referred to as TCP/IP. In some embodiments, the TCP/IP protocol may be carried over the Ethernet protocol, which may comprise any of the family of IEEE wide-area-network (WAN) or local-area-network (LAN) protocols, such as those protocols covered by the IEEE 802.3. In some embodiments, the network stack310comprises any type and form of a wireless protocol, such as IEEE 802.11 and/or mobile internet protocol.

In view of a TCP/IP based network, any TCP/IP based protocol may be used, including Messaging Application Programming Interface (MAPI) (email), File Transfer Protocol (FTP), HyperText Transfer Protocol (HTTP), Common Internet File System (CIFS) protocol (file transfer), Independent Computing Architecture (ICA) protocol, Remote Desktop Protocol (RDP), Wireless Application Protocol (WAP), Mobile IP protocol, and Voice Over IP (VoIP) protocol. In another embodiment, the network stack310comprises any type and form of transport control protocol, such as a modified transport control protocol, for example a Transaction TCP (T/TCP), TCP with selection acknowledgements (TCP-SACK), TCP with large windows (TCP-LW), a congestion prediction protocol such as the TCP-Vegas protocol, and a TCP spoofing protocol. In other embodiments, any type and form of user datagram protocol (UDP), such as UDP over IP, may be used by the network stack310, such as for voice communications or real-time data communications.

Furthermore, the network stack310may include one or more network drivers supporting the one or more layers, such as a TCP driver or a network layer driver. The network drivers may be included as part of the operating system of the computing device100or as part of any network interface cards or other network access components of the computing device100. In some embodiments, any of the network drivers of the network stack310may be customized, modified or adapted to provide a custom or modified portion of the network stack310in support of any of the techniques described herein. In other embodiments, the acceleration program120is designed and constructed to operate with or work in conjunction with the network stack310installed or otherwise provided by the operating system of the client102.

The network stack310comprises any type and form of interfaces for receiving, obtaining, providing or otherwise accessing any information and data related to network communications of the client102. In one embodiment, an interface to the network stack310comprises an application programming interface (API). The interface may also comprise any function call, hooking or filtering mechanism, event or call back mechanism, or any type of interfacing technique. The network stack310via the interface may receive or provide any type and form of data structure, such as an object, related to functionality or operation of the network stack310. For example, the data structure may comprise information and data related to a network packet or one or more network packets. In some embodiments, the data structure comprises a portion of the network packet processed at a protocol layer of the network stack310, such as a network packet of the transport layer. In some embodiments, the data structure325comprises a kernel-level data structure, while in other embodiments, the data structure325comprises a user-mode data structure. A kernel-level data structure may comprise a data structure obtained or related to a portion of the network stack310operating in kernel-mode302, or a network driver or other software running in kernel-mode302, or any data structure obtained or received by a service, process, task, thread or other executable instructions running or operating in kernel-mode of the operating system.

Additionally, some portions of the network stack310may execute or operate in kernel-mode302, for example, the data link or network layer, while other portions execute or operate in user-mode303, such as an application layer of the network stack310. For example, a first portion310aof the network stack may provide user-mode access to the network stack310to an application while a second portion310aof the network stack310provides access to a network. In some embodiments, a first portion310aof the network stack may comprise one or more upper layers of the network stack310, such as any of layers5-7. In other embodiments, a second portion310bof the network stack310comprises one or more lower layers, such as any of layers1-4. Each of the first portion310aand second portion310bof the network stack310may comprise any portion of the network stack310, at any one or more network layers, in user-mode203, kernel-mode,202, or combinations thereof, or at any portion of a network layer or interface point to a network layer or any portion of or interface point to the user-mode203and kernel-mode203.

The interceptor350may comprise software, hardware, or any combination of software and hardware. In one embodiment, the interceptor350intercept a network communication at any point in the network stack310, and redirects or transmits the network communication to a destination desired, managed or controlled by the interceptor350or client agent120. For example, the interceptor350may intercept a network communication of a network stack310of a first network and transmit the network communication to the appliance200for transmission on a second network104. In some embodiments, the interceptor350comprises any type interceptor350comprises a driver, such as a network driver constructed and designed to interface and work with the network stack310. In some embodiments, the client agent120and/or interceptor350operates at one or more layers of the network stack310, such as at the transport layer. In one embodiment, the interceptor350comprises a filter driver, hooking mechanism, or any form and type of suitable network driver interface that interfaces to the transport layer of the network stack, such as via the transport driver interface (TDI). In some embodiments, the interceptor350interfaces to a first protocol layer, such as the transport layer and another protocol layer, such as any layer above the transport protocol layer, for example, an application protocol layer. In one embodiment, the interceptor350may comprise a driver complying with the Network Driver Interface Specification (NDIS), or a NDIS driver. In another embodiment, the interceptor350may comprise a min-filter or a mini-port driver. In one embodiment, the interceptor350, or portion thereof, operates in kernel-mode202. In another embodiment, the interceptor350, or portion thereof, operates in user-mode203. In some embodiments, a portion of the interceptor350operates in kernel-mode202while another portion of the interceptor350operates in user-mode203. In other embodiments, the client agent120operates in user-mode203but interfaces via the interceptor350to a kernel-mode driver, process, service, task or portion of the operating system, such as to obtain a kernel-level data structure225. In further embodiments, the interceptor350is a user-mode application or program, such as application.

In one embodiment, the interceptor350intercepts any transport layer connection requests. In these embodiments, the interceptor350execute transport layer application programming interface (API) calls to set the destination information, such as destination IP address and/or port to a desired location for the location. In this manner, the interceptor350intercepts and redirects the transport layer connection to a IP address and port controlled or managed by the interceptor350or client agent120. In one embodiment, the interceptor350sets the destination information for the connection to a local IP address and port of the client102on which the client agent120is listening. For example, the client agent120may comprise a proxy service listening on a local IP address and port for redirected transport layer communications. In some embodiments, the client agent120then communicates the redirected transport layer communication to the appliance200.

In some embodiments, the interceptor350intercepts a Domain Name Service (DNS) request. In one embodiment, the client agent120and/or interceptor350resolves the DNS request. In another embodiment, the interceptor transmits the intercepted DNS request to the appliance200for DNS resolution. In one embodiment, the appliance200resolves the DNS request and communicates the DNS response to the client agent120. In some embodiments, the appliance200resolves the DNS request via another appliance200′ or a DNS server106.

In yet another embodiment, the client agent120may comprise two agents120and120′. In one embodiment, a first agent120may comprise an interceptor350operating at the network layer of the network stack310. In some embodiments, the first agent120intercepts network layer requests such as Internet Control Message Protocol (ICMP) requests (e.g., ping and traceroute). In other embodiments, the second agent120′ may operate at the transport layer and intercept transport layer communications. In some embodiments, the first agent120intercepts communications at one layer of the network stack210and interfaces with or communicates the intercepted communication to the second agent120′.

The client agent120and/or interceptor350may operate at or interface with a protocol layer in a manner transparent to any other protocol layer of the network stack310. For example, in one embodiment, the interceptor350operates or interfaces with the transport layer of the network stack310transparently to any protocol layer below the transport layer, such as the network layer, and any protocol layer above the transport layer, such as the session, presentation or application layer protocols. This allows the other protocol layers of the network stack310to operate as desired and without modification for using the interceptor350. As such, the client agent120and/or interceptor350can interface with the transport layer to secure, optimize, accelerate, route or load-balance any communications provided via any protocol carried by the transport layer, such as any application layer protocol over TCP/IP.

Furthermore, the client agent120and/or interceptor may operate at or interface with the network stack310in a manner transparent to any application, a user of the client102, and any other computing device, such as a server, in communications with the client102. The client agent120and/or interceptor350may be installed and/or executed on the client102in a manner without modification of an application. In some embodiments, the user of the client102or a computing device in communications with the client102are not aware of the existence, execution or operation of the client agent120and/or interceptor350. As such, in some embodiments, the client agent120and/or interceptor350is installed, executed, and/or operated transparently to an application, user of the client102, another computing device, such as a server, or any of the protocol layers above and/or below the protocol layer interfaced to by the interceptor350.

The client agent120includes an acceleration program302, a streaming client306, a collection agent304, and/or monitoring agent197. In one embodiment, the client agent120comprises an Independent Computing Architecture (ICA) client, or any portion thereof, developed by Citrix Systems, Inc. of Fort Lauderdale, Fla., and is also referred to as an ICA client. In some embodiments, the client120comprises an application streaming client306for streaming an application from a server106to a client102. In some embodiments, the client agent120comprises an acceleration program302for accelerating communications between client102and server106. In another embodiment, the client agent120includes a collection agent304for performing end-point detection/scanning and collecting end-point information for the appliance200and/or server106.

In some embodiments, the acceleration program302comprises a client-side acceleration program for performing one or more acceleration techniques to accelerate, enhance or otherwise improve a client's communications with and/or access to a server106, such as accessing an application provided by a server106. The logic, functions, and/or operations of the executable instructions of the acceleration program302may perform one or more of the following acceleration techniques: 1) multi-protocol compression, 2) transport control protocol pooling, 3) transport control protocol multiplexing, 4) transport control protocol buffering, and 5) caching via a cache manager. Additionally, the acceleration program302may perform encryption and/or decryption of any communications received and/or transmitted by the client102. In some embodiments, the acceleration program302performs one or more of the acceleration techniques in an integrated manner or fashion. Additionally, the acceleration program302can perform compression on any of the protocols, or multiple-protocols, carried as a payload of a network packet of the transport layer protocol.

The streaming client306comprises an application, program, process, service, task or executable instructions for receiving and executing a streamed application from a server106. A server106may stream one or more application data files to the streaming client306for playing, executing or otherwise causing to be executed the application on the client102. In some embodiments, the server106transmits a set of compressed or packaged application data files to the streaming client306. In some embodiments, the plurality of application files are compressed and stored on a file server within an archive file such as a CAB, ZIP, SIT, TAR, JAR or other archive. In one embodiment, the server106decompresses, unpackages or unarchives the application files and transmits the files to the client102. In another embodiment, the client102decompresses, unpackages or unarchives the application files. The streaming client306dynamically installs the application, or portion thereof, and executes the application. In one embodiment, the streaming client306may be an executable program. In some embodiments, the streaming client306may be able to launch another executable program.

The collection agent304comprises an application, program, process, service, task or executable instructions for identifying, obtaining and/or collecting information about the client102. In some embodiments, the appliance200transmits the collection agent304to the client102or client agent120. The collection agent304may be configured according to one or more policies of the policy engine236of the appliance. In other embodiments, the collection agent304transmits collected information on the client102to the appliance200. In one embodiment, the policy engine236of the appliance200uses the collected information to determine and provide access, authentication and authorization control of the client's connection to a network104.

In one embodiment, the collection agent304comprises an end-point detection and scanning mechanism, which identifies and determines one or more attributes or characteristics of the client. For example, the collection agent304may identify and determine any one or more of the following client-side attributes: 1) the operating system an/or a version of an operating system, 2) a service pack of the operating system, 3) a running service, 4) a running process, and 5) a file. The collection agent304may also identify and determine the presence or versions of any one or more of the following on the client: 1) antivirus software, 2) personal firewall software, 3) anti-spam software, and 4) internet security software. The policy engine236may have one or more policies based on any one or more of the attributes or characteristics of the client or client-side attributes.

In some embodiments, the client agent120includes a monitoring agent197as discussed in conjunction withFIGS. 1D and 2B. The monitoring agent197may be any type and form of script, such as Visual Basic or Java script. In one embodiment, the monitoring agent129monitors and measures performance of any portion of the client agent120. For example, in some embodiments, the monitoring agent129monitors and measures performance of the acceleration program302. In another embodiment, the monitoring agent129monitors and measures performance of the streaming client306. In other embodiments, the monitoring agent129monitors and measures performance of the collection agent304. In still another embodiment, the monitoring agent129monitors and measures performance of the interceptor350. In some embodiments, the monitoring agent129monitors and measures any resource of the client102, such as memory, CPU and disk.

The monitoring agent197may monitor and measure performance of any application of the client. In one embodiment, the monitoring agent129monitors and measures performance of a browser on the client102. In some embodiments, the monitoring agent197monitors and measures performance of any application delivered via the client agent120. In other embodiments, the monitoring agent197measures and monitors end user response times for an application, such as web-based or HTTP response times. The monitoring agent197may monitor and measure performance of an ICA or RDP client. In another embodiment, the monitoring agent197measures and monitors metrics for a user session or application session. In some embodiments, monitoring agent197measures and monitors an ICA or RDP session. In one embodiment, the monitoring agent197measures and monitors the performance of the appliance200in accelerating delivery of an application and/or data to the client102.

In some embodiments and still referring toFIG. 3, a first program322may be used to install and/or execute the client agent120, or portion thereof, such as the interceptor350, automatically, silently, transparently, or otherwise. In one embodiment, the first program322comprises a plugin component, such an ActiveX control or Java control or script that is loaded into and executed by an application. For example, the first program comprises an ActiveX control loaded and run by a web browser application, such as in the memory space or context of the application. In another embodiment, the first program322comprises a set of executable instructions loaded into and run by the application, such as a browser. In one embodiment, the first program322comprises a designed and constructed program to install the client agent120. In some embodiments, the first program322obtains, downloads, or receives the client agent120via the network from another computing device. In another embodiment, the first program322is an installer program or a plug and play manager for installing programs, such as network drivers, on the operating system of the client102.

D. Systems and Methods for Providing Virtualized Application Delivery Controller

Referring now toFIG. 4A, a block diagram depicts one embodiment of a virtualization environment400. In brief overview, a computing device100includes a hypervisor layer, a virtualization layer, and a hardware layer. The hypervisor layer includes a hypervisor401(also referred to as a virtualization manager) that allocates and manages access to a number of physical resources in the hardware layer (e.g., the processor(s)421, and disk(s)428) by at least one virtual machine executing in the virtualization layer. The virtualization layer includes at least one operating system410and a plurality of virtual resources allocated to the at least one operating system410. Virtual resources may include, without limitation, a plurality of virtual processors432a,432b,432c(generally432), and virtual disks442a,442b,442c(generally442), as well as virtual resources such as virtual memory and virtual network interfaces. The plurality of virtual resources and the operating system410may be referred to as a virtual machine406. A virtual machine406may include a control operating system405in communication with the hypervisor401and used to execute applications for managing and configuring other virtual machines on the computing device100.

In greater detail, a hypervisor401may provide virtual resources to an operating system in any manner which simulates the operating system having access to a physical device. A hypervisor401may provide virtual resources to any number of guest operating systems410a,410b(generally410). In some embodiments, a computing device100executes one or more types of hypervisors. In these embodiments, hypervisors may be used to emulate virtual hardware, partition physical hardware, virtualize physical hardware, and execute virtual machines that provide access to computing environments. Hypervisors may include those manufactured by VMWare, Inc., of Palo Alto, Calif.; the XEN hypervisor, an open source product whose development is overseen by the open source Xen.org community; HyperV, VirtualServer or virtual PC hypervisors provided by Microsoft, or others. In some embodiments, a computing device100executing a hypervisor that creates a virtual machine platform on which guest operating systems may execute is referred to as a host server. In one of these embodiments, for example, the computing device100is a XEN SERVER provided by Citrix Systems, Inc., of Fort Lauderdale, Fla.

In some embodiments, a hypervisor401executes within an operating system executing on a computing device. In one of these embodiments, a computing device executing an operating system and a hypervisor401may be said to have a host operating system (the operating system executing on the computing device), and a guest operating system (an operating system executing within a computing resource partition provided by the hypervisor401). In other embodiments, a hypervisor401interacts directly with hardware on a computing device, instead of executing on a host operating system. In one of these embodiments, the hypervisor401may be said to be executing on “bare metal,” referring to the hardware comprising the computing device.

In some embodiments, a hypervisor401may create a virtual machine406a-c(generally406) in which an operating system410executes. In one of these embodiments, for example, the hypervisor401loads a virtual machine image to create a virtual machine406. In another of these embodiments, the hypervisor401executes an operating system410within the virtual machine406. In still another of these embodiments, the virtual machine406executes an operating system410.

In some embodiments, the hypervisor401controls processor scheduling and memory partitioning for a virtual machine406executing on the computing device100. In one of these embodiments, the hypervisor401controls the execution of at least one virtual machine406. In another of these embodiments, the hypervisor401presents at least one virtual machine406with an abstraction of at least one hardware resource provided by the computing device100. In other embodiments, the hypervisor401controls whether and how physical processor capabilities are presented to the virtual machine406.

A control operating system405may execute at least one application for managing and configuring the guest operating systems. In one embodiment, the control operating system405may execute an administrative application, such as an application including a user interface providing administrators with access to functionality for managing the execution of a virtual machine, including functionality for executing a virtual machine, terminating an execution of a virtual machine, or identifying a type of physical resource for allocation to the virtual machine. In another embodiment, the hypervisor401executes the control operating system405within a virtual machine406created by the hypervisor401. In still another embodiment, the control operating system405executes in a virtual machine406that is authorized to directly access physical resources on the computing device100. In some embodiments, a control operating system405aon a computing device100amay exchange data with a control operating system405bon a computing device100b, via communications between a hypervisor401aand a hypervisor401b. In this way, one or more computing devices100may exchange data with one or more of the other computing devices100regarding processors and other physical resources available in a pool of resources. In one of these embodiments, this functionality allows a hypervisor to manage a pool of resources distributed across a plurality of physical computing devices. In another of these embodiments, multiple hypervisors manage one or more of the guest operating systems executed on one of the computing devices100.

In one embodiment, the control operating system405executes in a virtual machine406that is authorized to interact with at least one guest operating system410. In another embodiment, a guest operating system410communicates with the control operating system405via the hypervisor401in order to request access to a disk or a network. In still another embodiment, the guest operating system410and the control operating system405may communicate via a communication channel established by the hypervisor401, such as, for example, via a plurality of shared memory pages made available by the hypervisor401.

In some embodiments, the control operating system405includes a network back-end driver for communicating directly with networking hardware provided by the computing device100. In one of these embodiments, the network back-end driver processes at least one virtual machine request from at least one guest operating system110. In other embodiments, the control operating system405includes a block back-end driver for communicating with a storage element on the computing device100. In one of these embodiments, the block back-end driver reads and writes data from the storage element based upon at least one request received from a guest operating system410.

In one embodiment, the control operating system405includes a tools stack404. In another embodiment, a tools stack404provides functionality for interacting with the hypervisor401, communicating with other control operating systems405(for example, on a second computing device100b), or managing virtual machines406b,406con the computing device100. In another embodiment, the tools stack404includes customized applications for providing improved management functionality to an administrator of a virtual machine farm. In some embodiments, at least one of the tools stack404and the control operating system405include a management API that provides an interface for remotely configuring and controlling virtual machines406running on a computing device100. In other embodiments, the control operating system405communicates with the hypervisor401through the tools stack104.

In one embodiment, the hypervisor401executes a guest operating system410within a virtual machine406created by the hypervisor401. In another embodiment, the guest operating system410provides a user of the computing device100with access to resources within a computing environment. In still another embodiment, a resource includes a program, an application, a document, a file, a plurality of applications, a plurality of files, an executable program file, a desktop environment, a computing environment, or other resource made available to a user of the computing device100. In yet another embodiment, the resource may be delivered to the computing device100via a plurality of access methods including, but not limited to, conventional installation directly on the computing device100, delivery to the computing device100via a method for application streaming, delivery to the computing device100of output data generated by an execution of the resource on a second computing device100′ and communicated to the computing device100via a presentation layer protocol, delivery to the computing device100of output data generated by an execution of the resource via a virtual machine executing on a second computing device100′, or execution from a removable storage device connected to the computing device100, such as a USB device, or via a virtual machine executing on the computing device100and generating output data. In some embodiments, the computing device100transmits output data generated by the execution of the resource to another computing device100′.

In one embodiment, the guest operating system410, in conjunction with the virtual machine on which it executes, forms a fully-virtualized virtual machine which is not aware that it is a virtual machine; such a machine may be referred to as a “Domain U HVM (Hardware Virtual Machine) virtual machine”. In another embodiment, a fully-virtualized machine includes software emulating a Basic Input/Output System (BIOS) in order to execute an operating system within the fully-virtualized machine. In still another embodiment, a fully-virtualized machine may include a driver that provides functionality by communicating with the hypervisor401. In such an embodiment, the driver may be aware that it executes within a virtualized environment. In another embodiment, the guest operating system410, in conjunction with the virtual machine on which it executes, forms a paravirtualized virtual machine, which is aware that it is a virtual machine; such a machine may be referred to as a “Domain U PV virtual machine”. In another embodiment, a paravirtualized machine includes additional drivers that a fully-virtualized machine does not include. In still another embodiment, the paravirtualized machine includes the network back-end driver and the block back-end driver included in a control operating system405, as described above.

Referring now toFIG. 4B, a block diagram depicts one embodiment of a plurality of networked computing devices in a system in which at least one physical host executes a virtual machine. In brief overview, the system includes a management component404and a hypervisor401. The system includes a plurality of computing devices100, a plurality of virtual machines406, a plurality of hypervisors401, a plurality of management components referred to as tools stacks404, and a physical resource421,428. The plurality of physical machines100may each be provided as computing devices100, described above in connection withFIGS. 1E-1Hand4A.

In greater detail, a physical disk428is provided by a computing device100and stores at least a portion of a virtual disk442. In some embodiments, a virtual disk442is associated with a plurality of physical disks428. In one of these embodiments, one or more computing devices100may exchange data with one or more of the other computing devices100regarding processors and other physical resources available in a pool of resources, allowing a hypervisor to manage a pool of resources distributed across a plurality of physical computing devices. In some embodiments, a computing device100on which a virtual machine406executes is referred to as a physical host100or as a host machine100.

The hypervisor executes on a processor on the computing device100. The hypervisor allocates, to a virtual disk, an amount of access to the physical disk. In one embodiment, the hypervisor401allocates an amount of space on the physical disk. In another embodiment, the hypervisor401allocates a plurality of pages on the physical disk. In some embodiments, the hypervisor provisions the virtual disk442as part of a process of initializing and executing a virtual machine450.

In one embodiment, the management component404ais referred to as a pool management component404a. In another embodiment, a management operating system405a, which may be referred to as a control operating system405a, includes the management component. In some embodiments, the management component is referred to as a tools stack. In one of these embodiments, the management component is the tools stack404described above in connection withFIG. 4A. In other embodiments, the management component404provides a user interface for receiving, from a user such as an administrator, an identification of a virtual machine406to provision and/or execute. In still other embodiments, the management component404provides a user interface for receiving, from a user such as an administrator, the request for migration of a virtual machine406bfrom one physical machine100to another. In further embodiments, the management component404aidentifies a computing device100bon which to execute a requested virtual machine406dand instructs the hypervisor401bon the identified computing device100bto execute the identified virtual machine; such a management component may be referred to as a pool management component.

Referring now toFIG. 4C, embodiments of a virtual application delivery controller or virtual appliance450are depicted. In brief overview, any of the functionality and/or embodiments of the appliance200(e.g., an application delivery controller) described above in connection withFIGS. 2A and 2Bmay be deployed in any embodiment of the virtualized environment described above in connection withFIGS. 4A and 4B. Instead of the functionality of the application delivery controller being deployed in the form of an appliance200, such functionality may be deployed in a virtualized environment400on any computing device100, such as a client102, server106or appliance200.

Referring now toFIG. 4C, a diagram of an embodiment of a virtual appliance450operating on a hypervisor401of a server106is depicted. As with the appliance200ofFIGS. 2A and 2B, the virtual appliance450may provide functionality for availability, performance, offload and security. For availability, the virtual appliance may perform load balancing between layers4and7of the network and may also perform intelligent service health monitoring. For performance increases via network traffic acceleration, the virtual appliance may perform caching and compression. To offload processing of any servers, the virtual appliance may perform connection multiplexing and pooling and/or SSL processing. For security, the virtual appliance may perform any of the application firewall functionality and SSL VPN function of appliance200.

Any of the modules of the appliance200as described in connection withFIG. 2Amay be packaged, combined, designed or constructed in a form of the virtualized appliance delivery controller450deployable as one or more software modules or components executable in a virtualized environment300or non-virtualized environment on any server, such as an off the shelf server. For example, the virtual appliance may be provided in the form of an installation package to install on a computing device. With reference toFIG. 2A, any of the cache manager232, policy engine236, compression238, encryption engine234, packet engine240, GUI210, CLI212, shell services214and health monitoring programs216may be designed and constructed as a software component or module to run on any operating system of a computing device and/or of a virtualized environment300. Instead of using the encryption processor260, processor262, memory264and network stack267of the appliance200, the virtualized appliance400may use any of these resources as provided by the virtualized environment400or as otherwise available on the server106.

Still referring toFIG. 4C, and in brief overview, any one or more vServers275A-275N may be in operation or executed in a virtualized environment400of any type of computing device100, such as any server106. Any of the modules or functionality of the appliance200described in connection withFIG. 2Bmay be designed and constructed to operate in either a virtualized or non-virtualized environment of a server. Any of the vServer275, SSL VPN280, Intranet UP282, Switching284, DNS286, acceleration288, App FW280and monitoring agent may be packaged, combined, designed or constructed in a form of application delivery controller450deployable as one or more software modules or components executable on a device and/or virtualized environment400.

In some embodiments, a server may execute multiple virtual machines406a-406nin the virtualization environment with each virtual machine running the same or different embodiments of the virtual application delivery controller450. In some embodiments, the server may execute one or more virtual appliances450on one or more virtual machines on a core of a multi-core processing system. In some embodiments, the server may execute one or more virtual appliances450on one or more virtual machines on each processor of a multiple processor device.

E. Systems and Methods for Providing A Multi-Core Architecture

In accordance with Moore's Law, the number of transistors that may be placed on an integrated circuit may double approximately every two years. However, CPU speed increases may reach plateaus, for example CPU speed has been around 3.5-4 GHz range since 2005. In some cases, CPU manufacturers may not rely on CPU speed increases to gain additional performance. Some CPU manufacturers may add additional cores to their processors to provide additional performance. Products, such as those of software and networking vendors, that rely on CPUs for performance gains may improve their performance by leveraging these multi-core CPUs. The software designed and constructed for a single CPU may be redesigned and/or rewritten to take advantage of a multi-threaded, parallel architecture or otherwise a multi-core architecture.

A multi-core architecture of the appliance200, referred to as nCore or multi-core technology, allows the appliance in some embodiments to break the single core performance barrier and to leverage the power of multi-core CPUs. In the previous architecture described in connection withFIG. 2A, a single network or packet engine is run. The multiple cores of the nCore technology and architecture allow multiple packet engines to run concurrently and/or in parallel. With a packet engine running on each core, the appliance architecture leverages the processing capacity of additional cores. In some embodiments, this provides up to a 7× increase in performance and scalability.

Illustrated inFIG. 5Aare some embodiments of work, task, load or network traffic distribution across one or more processor cores according to a type of parallelism or parallel computing scheme, such as functional parallelism, data parallelism or flow-based data parallelism. In brief overview,FIG. 5Aillustrates embodiments of a multi-core system such as an appliance200′ with n-cores, a total of cores numbers 1 through N. In one embodiment, work, load or network traffic can be distributed among a first core505A, a second core505B, a third core505C, a fourth core505D, a fifth core505E, a sixth core505F, a seventh core505G, and so on such that distribution is across all or two or more of the n cores505N (hereinafter referred to collectively as cores505.) There may be multiple VIPs275each running on a respective core of the plurality of cores. There may be multiple packet engines240each running on a respective core of the plurality of cores. Any of the approaches used may lead to different, varying or similar work load or performance level515across any of the cores. For a functional parallelism approach, each core may run a different function of the functionalities provided by the packet engine, a VIP275or appliance200. In a data parallelism approach, data may be paralleled or distributed across the cores based on the Network Interface Card (NIC) or VIP275receiving the data. In another data parallelism approach, processing may be distributed across the cores by distributing data flows to each core.

In further detail toFIG. 5A, in some embodiments, load, work or network traffic can be distributed among cores505according to functional parallelism500. Functional parallelism may be based on each core performing one or more respective functions. In some embodiments, a first core may perform a first function while a second core performs a second function. In functional parallelism approach, the functions to be performed by the multi-core system are divided and distributed to each core according to functionality. In some embodiments, functional parallelism may be referred to as task parallelism and may be achieved when each processor or core executes a different process or function on the same or different data. The core or processor may execute the same or different code. In some cases, different execution threads or code may communicate with one another as they work. Communication may take place to pass data from one thread to the next as part of a workflow.

In some embodiments, distributing work across the cores505according to functional parallelism500, can comprise distributing network traffic according to a particular function such as network input/output management (NW I/O)510A, secure sockets layer (SSL) encryption and decryption510B and transmission control protocol (TCP) functions510C. This may lead to a work, performance or computing load515based on a volume or level of functionality being used. In some embodiments, distributing work across the cores505according to data parallelism540, can comprise distributing an amount of work515based on distributing data associated with a particular hardware or software component. In some embodiments, distributing work across the cores505according to flow-based data parallelism520, can comprise distributing data based on a context or flow such that the amount of work515A-N on each core may be similar, substantially equal or relatively evenly distributed.

In the case of the functional parallelism approach, each core may be configured to run one or more functionalities of the plurality of functionalities provided by the packet engine or VIP of the appliance. For example, core1may perform network I/O processing for the appliance200′ while core2performs TCP connection management for the appliance. Likewise, core3may perform SSL offloading while core4may perform layer7or application layer processing and traffic management. Each of the cores may perform the same function or different functions. Each of the cores may perform more than one function. Any of the cores may run any of the functionality or portions thereof identified and/or described in conjunction withFIGS. 2A and 2B. In this the approach, the work across the cores may be divided by function in either a coarse-grained or fine-grained manner. In some cases, as illustrated inFIG. 5A, division by function may lead to different cores running at different levels of performance or load515.

In the case of the functional parallelism approach, each core may be configured to run one or more functionalities of the plurality of functionalities provided by the packet engine of the appliance. For example, core1may perform network I/O processing for the appliance200′ while core2performs TCP connection management for the appliance. Likewise, core3may perform SSL offloading while core4may perform layer7or application layer processing and traffic management. Each of the cores may perform the same function or different functions. Each of the cores may perform more than one function. Any of the cores may run any of the functionality or portions thereof identified and/or described in conjunction withFIGS. 2A and 2B. In this the approach, the work across the cores may be divided by function in either a coarse-grained or fine-grained manner. In some cases, as illustrated inFIG. 5Adivision by function may lead to different cores running at different levels of load or performance.

The functionality or tasks may be distributed in any arrangement and scheme. For example,FIG. 5Billustrates a first core, Core1505A, processing applications and processes associated with network I/O functionality510A. Network traffic associated with network I/O, in some embodiments, can be associated with a particular port number. Thus, outgoing and incoming packets having a port destination associated with NW I/O510A will be directed towards Core1505A which is dedicated to handling all network traffic associated with the NW I/O port. Similarly, Core2505B is dedicated to handling functionality associated with SSL processing and Core4505D may be dedicated handling all TCP level processing and functionality.

WhileFIG. 5Aillustrates functions such as network I/O, SSL and TCP, other functions can be assigned to cores. These other functions can include any one or more of the functions or operations described herein. For example, any of the functions described in conjunction withFIGS. 2A and 2Bmay be distributed across the cores on a functionality basis. In some cases, a first VIP275A may run on a first core while a second VIP275B with a different configuration may run on a second core. In some embodiments, each core505can handle a particular functionality such that each core505can handle the processing associated with that particular function. For example, Core2505B may handle SSL offloading while Core4505D may handle application layer processing and traffic management.

In other embodiments, work, load or network traffic may be distributed among cores505according to any type and form of data parallelism540. In some embodiments, data parallelism may be achieved in a multi-core system by each core performing the same task or functionally on different pieces of distributed data. In some embodiments, a single execution thread or code controls operations on all pieces of data. In other embodiments, different threads or instructions control the operation, but may execute the same code. In some embodiments, data parallelism is achieved from the perspective of a packet engine, vServers (VIPs)275A-C, network interface cards (NIC)542D-E and/or any other networking hardware or software included on or associated with an appliance200. For example, each core may run the same packet engine or VIP code or configuration but operate on different sets of distributed data. Each networking hardware or software construct can receive different, varying or substantially the same amount of data, and as a result may have varying, different or relatively the same amount of load515

In the case of a data parallelism approach, the work may be divided up and distributed based on VIPs, NICs and/or data flows of the VIPs or NICs. In one of these approaches, the work of the multi-core system may be divided or distributed among the VIPs by having each VIP work on a distributed set of data. For example, each core may be configured to run one or more VIPs. Network traffic may be distributed to the core for each VIP handling that traffic. In another of these approaches, the work of the appliance may be divided or distributed among the cores based on which NIC receives the network traffic. For example, network traffic of a first NIC may be distributed to a first core while network traffic of a second NIC may be distributed to a second core. In some cases, a core may process data from multiple NICs.

WhileFIG. 5Aillustrates a single vServer associated with a single core505, as is the case for VIP1275A, VIP2275B and VIP3275C. In some embodiments, a single vServer can be associated with one or more cores505. In contrast, one or more vServers can be associated with a single core505. Associating a vServer with a core505may include that core505to process all functions associated with that particular vServer. In some embodiments, each core executes a VIP having the same code and configuration. In other embodiments, each core executes a VIP having the same code but different configuration. In some embodiments, each core executes a VIP having different code and the same or different configuration.

Like vServers, NICs can also be associated with particular cores505. In many embodiments, NICs can be connected to one or more cores505such that when a NIC receives or transmits data packets, a particular core505handles the processing involved with receiving and transmitting the data packets. In one embodiment, a single NIC can be associated with a single core505, as is the case with NIC1542D and NIC2542E. In other embodiments, one or more NICs can be associated with a single core505. In other embodiments, a single NIC can be associated with one or more cores505. In these embodiments, load could be distributed amongst the one or more cores505such that each core505processes a substantially similar amount of load. A core505associated with a NIC may process all functions and/or data associated with that particular NIC.

While distributing work across cores based on data of VIPs or NICs may have a level of independency, in some embodiments, this may lead to unbalanced use of cores as illustrated by the varying loads515ofFIG. 5A.

In some embodiments, load, work or network traffic can be distributed among cores505based on any type and form of data flow. In another of these approaches, the work may be divided or distributed among cores based on data flows. For example, network traffic between a client and a server traversing the appliance may be distributed to and processed by one core of the plurality of cores. In some cases, the core initially establishing the session or connection may be the core for which network traffic for that session or connection is distributed. In some embodiments, the data flow is based on any unit or portion of network traffic, such as a transaction, a request/response communication or traffic originating from an application on a client. In this manner and in some embodiments, data flows between clients and servers traversing the appliance200′ may be distributed in a more balanced manner than the other approaches.

In flow-based data parallelism520, distribution of data is related to any type of flow of data, such as request/response pairings, transactions, sessions, connections or application communications. For example, network traffic between a client and a server traversing the appliance may be distributed to and processed by one core of the plurality of cores. In some cases, the core initially establishing the session or connection may be the core for which network traffic for that session or connection is distributed. The distribution of data flow may be such that each core505carries a substantially equal or relatively evenly distributed amount of load, data or network traffic.

In some embodiments, the data flow is based on any unit or portion of network traffic, such as a transaction, a request/response communication or traffic originating from an application on a client. In this manner and in some embodiments, data flows between clients and servers traversing the appliance200′ may be distributed in a more balanced manner than the other approached. In one embodiment, data flow can be distributed based on a transaction or a series of transactions. This transaction, in some embodiments, can be between a client and a server and can be characterized by an IP address or other packet identifier. For example, Core1505A can be dedicated to transactions between a particular client and a particular server, therefore the load536A on Core1505A may be comprised of the network traffic associated with the transactions between the particular client and server. Allocating the network traffic to Core1505A can be accomplished by routing all data packets originating from either the particular client or server to Core1505A.

While work or load can be distributed to the cores based in part on transactions, in other embodiments load or work can be allocated on a per packet basis. In these embodiments, the appliance200can intercept data packets and allocate them to a core505having the least amount of load. For example, the appliance200could allocate a first incoming data packet to Core1505A because the load536A on Core1is less than the load536B-N on the rest of the cores505B-N. Once the first data packet is allocated to Core1505A, the amount of load536A on Core1505A is increased proportional to the amount of processing resources needed to process the first data packet. When the appliance200intercepts a second data packet, the appliance200will allocate the load to Core4505D because Core4505D has the second least amount of load. Allocating data packets to the core with the least amount of load can, in some embodiments, ensure that the load536A-N distributed to each core505remains substantially equal.

In other embodiments, load can be allocated on a per unit basis where a section of network traffic is allocated to a particular core505. The above-mentioned example illustrates load balancing on a per/packet basis. In other embodiments, load can be allocated based on a number of packets such that every 10, 100 or 1000 packets are allocated to the core505having the least amount of load. The number of packets allocated to a core505can be a number determined by an application, user or administrator and can be any number greater than zero. In still other embodiments, load can be allocated based on a time metric such that packets are distributed to a particular core505for a predetermined amount of time. In these embodiments, packets can be distributed to a particular core505for five milliseconds or for any period of time determined by a user, program, system, administrator or otherwise. After the predetermined time period elapses, data packets are transmitted to a different core505for the predetermined period of time.

Flow-based data parallelism methods for distributing work, load or network traffic among the one or more cores505can comprise any combination of the above-mentioned embodiments. These methods can be carried out by any part of the appliance200, by an application or set of executable instructions executing on one of the cores505, such as the packet engine, or by any application, program or agent executing on a computing device in communication with the appliance200.

The functional and data parallelism computing schemes illustrated inFIG. 5Acan be combined in any manner to generate a hybrid parallelism or distributed processing scheme that encompasses function parallelism500, data parallelism540, flow-based data parallelism520or any portions thereof. In some cases, the multi-core system may use any type and form of load balancing schemes to distribute load among the one or more cores505. The load balancing scheme may be used in any combination with any of the functional and data parallelism schemes or combinations thereof.

Illustrated inFIG. 5Bis an embodiment of a multi-core system545, which may be any type and form of one or more systems, appliances, devices or components. This system545, in some embodiments, can be included within an appliance200having one or more processing cores505A-N. The system545can further include one or more packet engines (PE) or packet processing engines (PPE)548A-N communicating with a memory bus556. The memory bus may be used to communicate with the one or more processing cores505A-N. Also included within the system545can be one or more network interface cards (NIC)552and a flow distributor550which can further communicate with the one or more processing cores505A-N. The flow distributor550can comprise a Receive Side Scaler (RSS) or Receive Side Scaling (RSS) module560.

Further referring toFIG. 5B, and in more detail, in one embodiment the packet engine(s)548A-N can comprise any portion of the appliance200described herein, such as any portion of the appliance described inFIGS. 2A and 2B. The packet engine(s)548A-N can, in some embodiments, comprise any of the following elements: the packet engine240, a network stack267; a cache manager232; a policy engine236; a compression engine238; an encryption engine234; a GUI210; a CLI212; shell services214; monitoring programs216; and any other software or hardware element able to receive data packets from one of either the memory bus556or the one of more cores505A-N. In some embodiments, the packet engine(s)548A-N can comprise one or more vServers275A-N, or any portion thereof. In other embodiments, the packet engine(s)548A-N can provide any combination of the following functionalities: SSL VPN280; Intranet UP282; switching284; DNS286; packet acceleration288; App FW280; monitoring such as the monitoring provided by a monitoring agent197; functionalities associated with functioning as a TCP stack; load balancing; SSL offloading and processing; content switching; policy evaluation; caching; compression; encoding; decompression; decoding; application firewall functionalities; XML processing and acceleration; and SSL VPN connectivity.

The packet engine(s)548A-N can, in some embodiments, be associated with a particular server, user, client or network. When a packet engine548becomes associated with a particular entity, that packet engine548can process data packets associated with that entity. For example, should a packet engine548be associated with a first user, that packet engine548will process and operate on packets generated by the first user, or packets having a destination address associated with the first user. Similarly, the packet engine548may choose not to be associated with a particular entity such that the packet engine548can process and otherwise operate on any data packets not generated by that entity or destined for that entity.

In some instances, the packet engine(s)548A-N can be configured to carry out the any of the functional and/or data parallelism schemes illustrated inFIG. 5A. In these instances, the packet engine(s)548A-N can distribute functions or data among the processing cores505A-N so that the distribution is according to the parallelism or distribution scheme. In some embodiments, a single packet engine(s)548A-N carries out a load balancing scheme, while in other embodiments one or more packet engine(s)548A-N carry out a load balancing scheme. Each core505A-N, in one embodiment, can be associated with a particular packet engine505such that load balancing can be carried out by the packet engine505. Load balancing may in this embodiment, require that each packet engine505associated with a core505communicate with the other packet engines505associated with cores505so that the packet engines505can collectively determine where to distribute load. One embodiment of this process can include an arbiter that receives votes from each packet engine505for load. The arbiter can distribute load to each packet engine505based in part on the age of the engine's vote and in some cases a priority value associated with the current amount of load on an engine's associated core505.

Any of the packet engines running on the cores may run in user mode, kernel or any combination thereof. In some embodiments, the packet engine operates as an application or program running is user or application space. In these embodiments, the packet engine may use any type and form of interface to access any functionality provided by the kernel. In some embodiments, the packet engine operates in kernel mode or as part of the kernel. In some embodiments, a first portion of the packet engine operates in user mode while a second portion of the packet engine operates in kernel mode. In some embodiments, a first packet engine on a first core executes in kernel mode while a second packet engine on a second core executes in user mode. In some embodiments, the packet engine or any portions thereof operates on or in conjunction with the NIC or any drivers thereof.

In some embodiments the memory bus556can be any type and form of memory or computer bus. While a single memory bus556is depicted inFIG. 5B, the system545can comprise any number of memory buses556. In one embodiment, each packet engine548can be associated with one or more individual memory buses556.

The NIC552can in some embodiments be any of the network interface cards or mechanisms described herein. The NIC552can have any number of ports. The NIC can be designed and constructed to connect to any type and form of network104. While a single NIC552is illustrated, the system545can comprise any number of NICs552. In some embodiments, each core505A-N can be associated with one or more single NICs552. Thus, each core505can be associated with a single NIC552dedicated to a particular core505. The cores505A-N can comprise any of the processors described herein. Further, the cores505A-N can be configured according to any of the core505configurations described herein. Still further, the cores505A-N can have any of the core505functionalities described herein. WhileFIG. 5Billustrates seven cores505A-G, any number of cores505can be included within the system545. In particular, the system545can comprise “N” cores, where “N” is a whole number greater than zero.

A core may have or use memory that is allocated or assigned for use to that core. The memory may be considered private or local memory of that core and only accessible by that core. A core may have or use memory that is shared or assigned to multiple cores. The memory may be considered public or shared memory that is accessible by more than one core. A core may use any combination of private and public memory. With separate address spaces for each core, some level of coordination is eliminated from the case of using the same address space. With a separate address space, a core can perform work on information and data in the core's own address space without worrying about conflicts with other cores. Each packet engine may have a separate memory pool for TCP and/or SSL connections.

Further referring toFIG. 5B, any of the functionality and/or embodiments of the cores505described above in connection withFIG. 5Acan be deployed in any embodiment of the virtualized environment described above in connection withFIGS. 4A and 4B. Instead of the functionality of the cores505being deployed in the form of a physical processor505, such functionality may be deployed in a virtualized environment400on any computing device100, such as a client102, server106or appliance200. In other embodiments, instead of the functionality of the cores505being deployed in the form of an appliance or a single device, the functionality may be deployed across multiple devices in any arrangement. For example, one device may comprise two or more cores and another device may comprise two or more cores. For example, a multi-core system may include a cluster of computing devices, a server farm or network of computing devices. In some embodiments, instead of the functionality of the cores505being deployed in the form of cores, the functionality may be deployed on a plurality of processors, such as a plurality of single core processors.

In one embodiment, the cores505may be any type and form of processor. In some embodiments, a core can function substantially similar to any processor or central processing unit described herein. In some embodiment, the cores505may comprise any portion of any processor described herein. WhileFIG. 5Aillustrates seven cores, there can exist any “N” number of cores within an appliance200, where “N” is any whole number greater than one. In some embodiments, the cores505can be installed within a common appliance200, while in other embodiments the cores505can be installed within one or more appliance(s)200communicatively connected to one another. The cores505can in some embodiments comprise graphics processing software, while in other embodiments the cores505provide general processing capabilities. The cores505can be installed physically near each other and/or can be communicatively connected to each other. The cores may be connected by any type and form of bus or subsystem physically and/or communicatively coupled to the cores for transferring data between to, from and/or between the cores.

While each core505can comprise software for communicating with other cores, in some embodiments a core manager (Not Shown) can facilitate communication between each core505. In some embodiments, the kernel may provide core management. The cores may interface or communicate with each other using a variety of interface mechanisms. In some embodiments, core to core messaging may be used to communicate between cores, such as a first core sending a message or data to a second core via a bus or subsystem connecting the cores. In some embodiments, cores may communicate via any type and form of shared memory interface. In one embodiment, there may be one or more memory locations shared among all the cores. In some embodiments, each core may have separate memory locations shared with each other core. For example, a first core may have a first shared memory with a second core and a second share memory with a third core. In some embodiments, cores may communicate via any type of programming or API, such as function calls via the kernel. In some embodiments, the operating system may recognize and support multiple core devices and provide interfaces and API for inter-core communications.

The flow distributor550can be any application, program, library, script, task, service, process or any type and form of executable instructions executing on any type and form of hardware. In some embodiments, the flow distributor550may any design and construction of circuitry to perform any of the operations and functions described herein. In some embodiments, the flow distributor distribute, forwards, routes, controls and/ors manage the distribution of data packets among the cores505and/or packet engine or VIPs running on the cores. The flow distributor550, in some embodiments, can be referred to as an interface master. In one embodiment, the flow distributor550comprises a set of executable instructions executing on a core or processor of the appliance200. In another embodiment, the flow distributor550comprises a set of executable instructions executing on a computing machine in communication with the appliance200. In some embodiments, the flow distributor550comprises a set of executable instructions executing on a NIC, such as firmware. In still other embodiments, the flow distributor550comprises any combination of software and hardware to distribute data packets among cores or processors. In one embodiment, the flow distributor550executes on at least one of the cores505A-N, while in other embodiments a separate flow distributor550assigned to each core505A-N executes on an associated core505A-N. The flow distributor may use any type and form of statistical or probabilistic algorithms or decision making to balance the flows across the cores. The hardware of the appliance, such as a NIC, or the kernel may be designed and constructed to support sequential operations across the NICs and/or cores.

In embodiments where the system545comprises one or more flow distributors550, each flow distributor550can be associated with a processor505or a packet engine548. The flow distributors550can comprise an interface mechanism that allows each flow distributor550to communicate with the other flow distributors550executing within the system545. In one instance, the one or more flow distributors550can determine how to balance load by communicating with each other. This process can operate substantially similarly to the process described above for submitting votes to an arbiter which then determines which flow distributor550should receive the load. In other embodiments, a first flow distributor550′ can identify the load on an associated core and determine whether to forward a first data packet to the associated core based on any of the following criteria: the load on the associated core is above a predetermined threshold; the load on the associated core is below a predetermined threshold; the load on the associated core is less than the load on the other cores; or any other metric that can be used to determine where to forward data packets based in part on the amount of load on a processor.

The flow distributor550can distribute network traffic among the cores505according to a distribution, computing or load balancing scheme such as those described herein. In one embodiment, the flow distributor can distribute network traffic or ;pad according to any one of a functional parallelism distribution scheme550, a data parallelism load distribution scheme540, a flow-based data parallelism distribution scheme520, or any combination of these distribution scheme or any load balancing scheme for distributing load among multiple processors. The flow distributor550can therefore act as a load distributor by taking in data packets and distributing them across the processors according to an operative load balancing or distribution scheme. In one embodiment, the flow distributor550can comprise one or more operations, functions or logic to determine how to distribute packers, work or load accordingly. In still other embodiments, the flow distributor550can comprise one or more sub operations, functions or logic that can identify a source address and a destination address associated with a data packet, and distribute packets accordingly.

In some embodiments, the flow distributor550can comprise a receive-side scaling (RSS) network driver, module560or any type and form of executable instructions which distribute data packets among the one or more cores505. The RSS module560can comprise any combination of hardware and software, In some embodiments, the RSS module560works in conjunction with the flow distributor550to distribute data packets across the cores505A-N or among multiple processors in a multi-processor network. The RSS module560can execute within the NIC552in some embodiments, and in other embodiments can execute on any one of the cores505.

In some embodiments, the RSS module560uses the MICROSOFT receive-side-scaling (RSS) scheme. In one embodiment, RSS is a Microsoft Scalable Networking initiative technology that enables receive processing to be balanced across multiple processors in the system while maintaining in-order delivery of the data. The RSS may use any type and form of hashing scheme to determine a core or processor for processing a network packet.

The RSS module560can apply any type and form hash function such as the Toeplitz hash function. The hash function may be applied to the hash type or any the sequence of values. The hash function may be a secure hash of any security level or is otherwise cryptographically secure. The has function may use a hash key. The size of the key is dependent upon the hash function. For the Toeplitz hash, the size may be 40 bytes for IPv6 and 16 bytes for IPv4.

The hash function may be designed and constructed based on any one or more criteria or design goals. In some embodiments, a hash function may be used that provides an even distribution of hash result for different hash inputs and different hash types, including TCP/IPv4, TCP/IPv6, IPv4, and IPv6 headers. In some embodiments, a hash function may be used that provides a hash result that is evenly distributed when a small number of buckets are present (for example, two or four). In some embodiments, hash function may be used that provides a hash result that is randomly distributed when a large number of buckets were present (for example, 64 buckets). In some embodiments, the hash function is determined based on a level of computational or resource usage. In some embodiments, the hash function is determined based on ease or difficulty of implementing the hash in hardware. In some embodiments, the hash function is determined bases on the ease or difficulty of a malicious remote host to send packets that would all hash to the same bucket.

The RSS may generate hashes from any type and form of input, such as a sequence of values. This sequence of values can include any portion of the network packet, such as any header, field or payload of network packet, or portions thereof. In some embodiments, the input to the hash may be referred to as a hash type and include any tuples of information associated with a network packet or data flow, such as any of the following: a four tuple comprising at least two IP addresses and two ports; a four tuple comprising any four sets of values; a six tuple; a two tuple; and/or any other sequence of numbers or values. The following are example of hash types that may be used by RSS:4-tuple of source TCP Port, source IP version 4 (IPv4) address, destination TCP Port, and destination IPv4 address. This is the only required hash type to support.4-tuple of source TCP Port, source IP version 6 (IPv6) address, destination TCP Port, and destination IPv6 address.2-tuple of source IPv4 address, and destination IPv4 address.2-tuple of source IPv6 address, and destination IPv6 address.2-tuple of source IPv6 address, and destination IPv6 address, including support for parsing IPv6 extension headers.

The hash result or any portion thereof may used to identify a core or entity, such as a packet engine or VIP, for distributing a network packet. In some embodiments, one or more hash bits or mask are applied to the hash result. The hash bit or mask may be any number of bits or bytes. A NIC may support any number of bits, such as seven bits. The network stack may set the actual number of bits to be used during initialization. The number will be between 1 and 7, inclusive.

The hash result may be used to identify the core or entity via any type and form of table, such as a bucket table or indirection table. In some embodiments, the number of hash-result bits are used to index into the table. The range of the hash mask may effectively define the size of the indirection table. Any portion of the hash result or the hast result itself may be used to index the indirection table. The values in the table may identify any of the cores or processor, such as by a core or processor identifier. In some embodiments, all of the cores of the multi-core system are identified in the table. In other embodiments, a port of the cores of the multi-core system are identified in the table. The indirection table may comprise any number of buckets for example 2 to 128 buckets that may be indexed by a hash mask. Each bucket may comprise a range of index values that identify a core or processor. In some embodiments, the flow controller and/or RSS module may rebalance the network rebalance the network load by changing the indirection table.

In some embodiments, the multi-core system575does not include a RSS driver or RSS module560. In some of these embodiments, a software steering module (Not Shown) or a software embodiment of the RSS module within the system can operate in conjunction with or as part of the flow distributor550to steer packets to cores505within the multi-core system575.

The flow distributor550, in some embodiments, executes within any module or program on the appliance200, on any one of the cores505and on any one of the devices or components included within the multi-core system575. In some embodiments, the flow distributor550′ can execute on the first core505A, while in other embodiments the flow distributor550″ can execute on the NIC552. In still other embodiments, an instance of the flow distributor550′ can execute on each core505included in the multi-core system575. In this embodiment, each instance of the flow distributor550′ can communicate with other instances of the flow distributor550′ to forward packets back and forth across the cores505. There exist situations where a response to a request packet may not be processed by the same core, i.e. the first core processes the request while the second core processes the response. In these situations, the instances of the flow distributor550′ can intercept the packet and forward it to the desired or correct core505, i.e. a flow distributor instance550′ can forward the response to the first core. Multiple instances of the flow distributor550′ can execute on any number of cores505and any combination of cores505.

The flow distributor may operate responsive to any one or more rules or policies. The rules may identify a core or packet processing engine to receive a network packet, data or data flow. The rules may identify any type and form of tuple information related to a network packet, such as a 4-tuple of source and destination IP address and source and destination ports. Based on a received packet matching the tuple specified by the rule, the flow distributor may forward the packet to a core or packet engine. In some embodiments, the packet is forwarded to a core via shared memory and/or core to core messaging.

AlthoughFIG. 5Billustrates the flow distributor550as executing within the multi-core system575, in some embodiments the flow distributor550can execute on a computing device or appliance remotely located from the multi-core system575. In such an embodiment, the flow distributor550can communicate with the multi-core system575to take in data packets and distribute the packets across the one or more cores505. The flow distributor550can, in one embodiment, receive data packets destined for the appliance200, apply a distribution scheme to the received data packets and distribute the data packets to the one or more cores505of the multi-core system575. In one embodiment, the flow distributor550can be included in a router or other appliance such that the router can target particular cores505by altering meta data associated with each packet so that each packet is targeted towards a sub-node of the multi-core system575. In such an embodiment, CISCO's vn-tag mechanism can be used to alter or tag each packet with the appropriate meta data.

Illustrated inFIG. 5Cis an embodiment of a multi-core system575comprising one or more processing cores505A-N. In brief overview, one of the cores505can be designated as a control core505A and can be used as a control plane570for the other cores505. The other cores may be secondary cores which operate in a data plane while the control core provides the control plane. The cores505A-N may share a global cache580. While the control core provides a control plane, the other cores in the multi-core system form or provide a data plane. These cores perform data processing functionality on network traffic while the control provides initialization, configuration and control of the multi-core system.

Further referring toFIG. 5C, and in more detail, the cores505A-N as well as the control core505A can be any processor described herein. Furthermore, the cores505A-N and the control core505A can be any processor able to function within the system575described inFIG. 5C. Still further, the cores505A-N and the control core505A can be any core or group of cores described herein. The control core may be a different type of core or processor than the other cores. In some embodiments, the control may operate a different packet engine or have a packet engine configured differently than the packet engines of the other cores.

Any portion of the memory of each of the cores may be allocated to or used for a global cache that is shared by the cores. In brief overview, a predetermined percentage or predetermined amount of each of the memory of each core may be used for the global cache. For example, 50% of each memory of each code may be dedicated or allocated to the shared global cache. That is, in the illustrated embodiment, 2 GB of each core excluding the control plane core or core1may be used to form a 28 GB shared global cache. The configuration of the control plane such as via the configuration services may determine the amount of memory used for the shared global cache. In some embodiments, each core may provide a different amount of memory for use by the global cache. In other embodiments, any one core may not provide any memory or use the global cache. In some embodiments, any of the cores may also have a local cache in memory not allocated to the global shared memory. Each of the cores may store any portion of network traffic to the global shared cache. Each of the cores may check the cache for any content to use in a request or response. Any of the cores may obtain content from the global shared cache to use in a data flow, request or response.

The global cache580can be any type and form of memory or storage element, such as any memory or storage element described herein. In some embodiments, the cores505may have access to a predetermined amount of memory (i.e. 32 GB or any other memory amount commensurate with the system575.) The global cache580can be allocated from that predetermined amount of memory while the rest of the available memory can be allocated among the cores505. In other embodiments, each core505can have a predetermined amount of memory. The global cache580can comprise an amount of the memory allocated to each core505. This memory amount can be measured in bytes, or can be measured as a percentage of the memory allocated to each core505. Thus, the global cache580can comprise 1 GB of memory from the memory associated with each core505, or can comprise 20 percent or one-half of the memory associated with each core505. In some embodiments, only a portion of the cores505provide memory to the global cache580, while in other embodiments the global cache580can comprise memory not allocated to the cores505.

Each core505can use the global cache580to store network traffic or cache data. In some embodiments, the packet engines of the core use the global cache to cache and use data stored by the plurality of packet engines. For example, the cache manager ofFIG. 2Aand cache functionality ofFIG. 2Bmay use the global cache to share data for acceleration. For example, each of the packet engines may store responses, such as HTML data, to the global cache. Any of the cache managers operating on a core may access the global cache to server caches responses to client requests.

In some embodiments, the cores505can use the global cache580to store a port allocation table which can be used to determine data flow based in part on ports. In other embodiments, the cores505can use the global cache580to store an address lookup table or any other table or list that can be used by the flow distributor to determine where to direct incoming and outgoing data packets. The cores505can, in some embodiments read from and write to cache580, while in other embodiments the cores505can only read from or write to cache580. The cores may use the global cache to perform core to core communications.

The global cache580may be sectioned into individual memory sections where each section can be dedicated to a particular core505. In one embodiment, the control core505A can receive a greater amount of available cache, while the other cores505can receiving varying amounts or access to the global cache580.

In some embodiments, the system575can comprise a control core505A. WhileFIG. 5Cillustrates core1505A as the control core, the control core can be any core within the appliance200or multi-core system. Further, while only a single control core is depicted, the system575can comprise one or more control cores each having a level of control over the system. In some embodiments, one or more control cores can each control a particular aspect of the system575. For example, one core can control deciding which distribution scheme to use, while another core can determine the size of the global cache580.

The control plane of the multi-core system may be the designation and configuration of a core as the dedicated management core or as a master core. This control plane core may provide control, management and coordination of operation and functionality the plurality of cores in the multi-core system. This control plane core may provide control, management and coordination of allocation and use of memory of the system among the plurality of cores in the multi-core system, including initialization and configuration of the same. In some embodiments, the control plane includes the flow distributor for controlling the assignment of data flows to cores and the distribution of network packets to cores based on data flows. In some embodiments, the control plane core runs a packet engine and in other embodiments, the control plane core is dedicated to management and control of the other cores of the system.

The control core505A can exercise a level of control over the other cores505such as determining how much memory should be allocated to each core505or determining which core505should be assigned to handle a particular function or hardware/software entity. The control core505A, in some embodiments, can exercise control over those cores505within the control plan570. Thus, there can exist processors outside of the control plane570which are not controlled by the control core505A. Determining the boundaries of the control plane570can include maintaining, by the control core505A or agent executing within the system575, a list of those cores505controlled by the control core505A. The control core505A can control any of the following: initialization of a core; determining when a core is unavailable; re-distributing load to other cores505when one core fails; determining which distribution scheme to implement; determining which core should receive network traffic; determining how much cache should be allocated to each core; determining whether to assign a particular function or element to a particular core; determining whether to permit cores to communicate with one another; determining the size of the global cache580; and any other determination of a function, configuration or operation of the cores within the system575.

F. Systems and Methods for Monitoring an Access Gateway

The systems and methods described herein are directed towards monitoring an access gateway by an intermediary device, such as appliance200. In general overview, the systems and methods include monitors (also referred to herein as “monitoring agents” or “probes”) that generate requests to access a logon agent or a login page service (collectively, “logon mechanisms”), or a Dynamic Desktop Controller service (“DDC”), such as for XenDesktop manufactured by Citrix Systems, Inc. The monitors evaluate the responses to the requests to determine if the status of the logon mechanisms or DDC service is available or unavailable. The monitors may evaluate the content of the responses for specific information that identifies the functional status of the login mechanism or DDC service. The monitors are login mechanism or service aware and understand the certain information should be in the content of the response that identifies whether or not the login mechanism or service is functioning as desired or intended. As a successful response may still provide content that does not allow the system to function properly, this provides more meaningful monitoring of status than whether or not a successful response is received. Based on evaluating this specific information, the monitors can provide the load balancing intermediary status based on functioning content to improve performance and operation of the system.

Although the present disclosure generally describes embodiments of the systems and methods in reference to logon mechanisms, the se systems and methods may be applied to monitoring DDC services. Although the present disclosure generally describes embodiments of the systems and methods in reference to logon mechanisms or a DDC services of an access gateway, these systems and methods may monitor these components executing in combination or separately on any computing device, such as a device not referred to or configured as an access gateway.

Although the system and methods described herein may be deployed on a single processor or core system, in some embodiments, the systems and methods herein may be deployed on a multi-core system. In some embodiments, the systems distribute ownership of monitors for the logon mechanisms on access gateways and ownership of monitoring the logon mechanisms, each of which may have one or more associated monitors, over a plurality of cores. If a core owns or is responsible for a monitor for a logon mechanism, the core may be responsible for sending probes to the logon mechanism according to the monitor and receiving the result of each probe. If a core owns or is responsible for monitoring a logon mechanism, the core may be responsible for tracking the status of the logon mechanism by processing the results of probes sent to the logon mechanism by itself or other cores. As a result, the workload for monitoring and tracking the statuses of logon mechanisms may be distributed across the plurality of cores.

Each core in the plurality of cores may be responsible for monitors for logon mechanisms, and each core may send probes to the logon mechanisms according to the monitors and receive the results. If a core is not responsible for the logon mechanism, the core may send the results of its probes for the logon mechanism to the owner core. If a core owns the logon mechanism, and is thus responsible for tracking the status of the logon mechanism, the core may determine the state of the logon mechanism. The core may determine the state of the logon mechanism by processing the results of probes for the logon mechanism. The core may determine the state of the logon mechanism by processing the results of probes sent by itself, probes sent by other cores, or both. The owner core may send messages to other cores regarding the state of the logon mechanism or a change in the state. The owner core responsible for the logon mechanism may be considered or referred to as the consolidator of the monitoring for the logon mechanism.

Referring now toFIG. 6A, a block diagram of an embodiment of a system600for monitoring a status of a login mechanism of an access gateway to a plurality of remote access servers, or a DDC service on the access gateway, is shown and described. In brief overview, the system600includes a client102seeking access to resources on the remote access servers602. The client102must be authenticated before the client102may access the resources. Although the present disclosure describes the client102obtaining authentication through login mechanisms610a,610bon the access gateway605, the client102may communicate with login mechanisms610on remote access servers602themselves or any other computing device that communicates with the remote access servers602for the necessary authentication.

In operation, a user at the client102types a URL of the access gateway605in the address field of a web browser. If the access gateway605detects an access token in the HTTP/S request, the access gateway605forwards the access token to the authentication service620for validation. If the authentication service620validates the access token, the access gateway605establishes a session between the client and the remote access servers602.

If the HTTP/S request has an expired access token or lacks an access token altogether, the access gateway605forwards the HTTP/S request to a logon mechanism610. In response, the logon mechanism610transmits a logon web page, which can include a URL, to the access gateway605to forward to the client102. The user enters credentials on the received web page and posts the credentials to the logon mechanism610through the access gateway605.

If the system600is configured for external authentication, the logon mechanism610may request the authentication service620to authenticate the credentials. If the authentication service620successfully authenticates the credentials, the authentication service620transmits an access token and URL for the client102. If the system600is configured for local authentication, the access gateway605verifies the received credentials and transmits the access token and URL to the client102.

The logon mechanism610sets the access token and any other remote access server-specific cookies, and transmits the access token, cookies, and URL to the client102via the access gateway605. The web browser on the client102is redirected to the URL through the access gateway605. The access gateway605extracts the access token from the client requests and presents the access token to the authentication service620for authentication. Upon successful authentication, the access gateway605forwards the client request to the remote access servers602to establish a session. Then, the access gateway605directs the client102to a web page from which a user may select a resource, available from the remote access server602, to access.

The access gateway605may comprise a logon point and a login agent service. The Logon Agent provides users a log on through a Web-based logon page into which the user enters logon credentials. The Logon Agent facilitates user authentication and authorization by contacting secure access management servers located within the secure network.

In example embodiment, a user connects to the Access Gateway405by typing the Web address in the browser. The user is presented with the logon page where the user name and password are entered. If external authentication servers are configured, the Access Gateway605contacts the server and the authentication servers verify the users' credentials. If local authentication is configured, user authentication is performed by the Access Gateway605.

In continued reference toFIG. 6A, and in further detail, the system600includes at least one appliance200with monitors650that monitor the status of the logon mechanisms610or DDC service612. For example, the monitors650may send requests to the logon mechanisms610or service612and determine from the responses whether the logon mechanisms610or service612are available, operational, and/or functional. Logon mechanisms610or DDC services612may become unavailable when the access gateway605has been taken off-line for maintenance or repair. Logon mechanisms610or DDC services612may also be unavailable when the number of incoming requests to the access gateway605for access to the remote access servers602or the service612exceeds the access gateway's605processing capacity. In these situations, the client's102connection to the access gateway605may time out before the access gateway605services the request.

In further examples, a monitor650may analyze a response from a logon mechanism610or DDC service612to determine whether the logon mechanism610is running, i.e. operational. If the monitor650receives a response, the monitor650may conclude the logon mechanism610or service612is operational. Further analysis of the response may reveal whether the logon mechanism610or service612is functioning properly. For example, if the response does not include valid responses expected from the logon mechanism610or DDC service612, the monitor650may determine or conclude that the logon mechanism610or DDC service612is non-functional.

If the monitor650determines that the logon mechanism610or DDC service612is unavailable, non-operational, or non-functional, the appliance200may identify the status of the login mechanism610or service612as Down or Unavailable. In some embodiments, the appliance may identify the login mechanism or service as out of service. Depending on the status, the appliance may remove the logon mechanism610or DDC service612from a load balancing scheme, either temporarily or permanently. The appliance may continue monitoring the login mechanism or service. If the login mechanism or service returns a response that indicates the login mechanism or service is operational and functional, the appliance may include the login mechanism or service into the load balancing scheme.

In some embodiments, the appliance200may also log an error with an administrative service. The logged entry may identify the logon mechanism610, the service612, the error, and/or the time and date of the error. A system administrator may examine the log and initiate a work order to correct the error.

A monitor650may comprise any application, program, script, daemon, or other computing routine or set of executable instruction to identify and/or report a status of a logon mechanism610or service612. The monitor may use any type and form of request and/or response communications at any protocol layer to determine a status of a login mechanism or service612. In some embodiments, the monitor sends an application layer protocol request to access a resource or URL of the login mechanism. For example, the monitor may generate and send an HTTP/s request The monitor may receive and evaluate the application layer protocol response to determine whether the login mechanism or service is operating and whether or not the login mechanism is functioning as desired or intended. For example, a200OK HTTP response indicates to the monitor that the login mechanism or service is operating. The monitor can search for and identify certain one or more predetermined elements with the body of the HTTP response to determine that the login mechanism or service is functional.

A monitor650may communicate with the logon mechanism610or service612once, or on a predetermined frequency, such as every 1 msec or 1 sec. In some embodiments, a monitor650may use a request/reply messaging mechanism or protocol with the logon mechanism610or service612. In other embodiments, a monitor650may have a custom or proprietary exchange protocol for communicating with the access gateway605. In some embodiments, a single monitor650may monitor a plurality of logon mechanism610on different access gateways605or remote access servers602. In other embodiments, a plurality of monitors650may monitor a single logon mechanism610. In still other embodiments, a plurality of monitors650may each monitor a plurality of logon mechanisms610, wherein each of the plurality of logon mechanisms610is monitored by a plurality of monitors650.

One or more monitors650may be associated with one or more logon mechanisms610or services612. The one or more monitoring agents650may be associated with one or more network services270A-270N. In other embodiments, the one or more monitoring agents may monitor an appliance200, vServer, network service270, client, or any other network resource. In one embodiment, a user specifies a type of network service to associate with the one or more monitoring agents420. In various embodiments, the monitors may monitor the Dynamic Desktop Controller service of XenDesktop, manufactured by Citrix Systems, Inc. of Fort Lauderdale, Fla.

In some embodiments, a generic monitor is used. In various embodiments, the one or more monitors650determine the status of a logon mechanism610or service612by analyzing a logon mechanism610response to a request of one of the following types: ping, transport control protocol (tcp), tcp extended content verification, hypertext transfer protocol (http), http extended content verification, hypertext transfer protocol secure (https), https extended content verification, user datagram protocol, domain name service, and file transfer protocol.

In some embodiments, the one or more monitoring agents650are protocol-specific agents, each agent determining availability for a network service of a particular protocol-type. In some embodiments, a monitoring agent650determines a response time of a server106or network service270to a TCP request. In one of these embodiments, the agent uses a “TCP/ICMP echo request” command to send a datagram to the network service270, receive a datagram from the network service270in response, and determine a response time based on the roundtrip time of the datagram. In another of these embodiments, the monitoring agent650verifies that the response from the network service270included expected content and did not contain errors.

In other embodiments, a monitoring agent650determines availability of a network service270to a UDP request. In one of these embodiments, the agent uses a “UDP echo” command to send a datagram to the network service270, receive a datagram from the network service270in response, and determine a response time based on the roundtrip time of the datagram. In another of these embodiments, the monitoring agent650verifies that the response from the network service270included expected content and did not contain errors.

In still other embodiments, the monitoring agent650determines availability of a network service270to an FTP request. In one of these embodiments, the monitoring agent650sends an FTP command, such as a “get” command or a “put” command, to the network service270and determines a time needed by the network service270to respond to the command. In another of these embodiments, the monitoring agent650verifies that the response from the network service270included expected content, such as contents of a file requested by a “get” command, and did not contain errors.

In yet other embodiments, the monitoring agent650determines availability of a network service270to an HTTP request. In one of these embodiments, the monitoring agent650sends an HTTP command, such as a “get” request for a uniform resource locator (URL) or a file, to the network service270and determines a time needed by the network service270to respond to the request. In another of these embodiments, the monitoring agent650verifies that the response from the network service270included expected content, such as the contents of a web page identified by the URL, and did not contain errors.

In further embodiments, the monitoring agent650determines availability of a network service270to a DNS request. In one of these embodiments, the monitoring agent650sends a DNS request, such as a dnsquery or nslookup for a known network address, to the server106or network service270and determines a time needed by the server106or network service270to respond to the request. In another of these embodiments, the monitoring agent650verifies that the response from the network service270included expected content, such as the domain name of a computing device100associated with the known network address, and did not contain errors.

A monitoring agent650may be assigned a weight by a network appliance200. A weight may comprise an integer, decimal, or any other numeric indicator. In some embodiments, a user may configure the weight corresponding to a given monitoring agent650. In some embodiments, all monitoring agents may be assigned equal weight. In other embodiments, a plurality of monitoring agents may each be assigned different weights. The weights may be assigned to the monitors based on any criteria indicating relative importance, including without limitation importance of the monitored service, reliability of the monitoring mechanism, and the frequency of monitoring.

In one embodiment, a monitoring agent650may be assigned a weight based on the relative importance of the service the appliance monitors. For example, if most user requests in a given environment were HTTP requests, a monitoring agent monitoring HTTP availability of a server106might be assigned a weight of 10, while a monitoring agent monitoring FTP availability of a server106might be assigned a weight of 3. Or, for example, if an administrator placed a high priority on UDP applications, a monitoring agent monitoring UDP availability of a server may be assigned a weight of 20, while a DNS monitoring agent may be assigned a weight of 5.

In some embodiments, an appliance200may compute a sum of the weights of the monitoring agents currently reporting a network service270as operational. For example, if five monitoring agents, each assigned a weight of 30, are monitoring a network service270, and three of the five monitoring agents report the network service270as available, the appliance may determine the sum of the monitoring agents currently reporting the network service270as operational to be 90. Or for example, if only two monitoring agents, one with a weight of 20 and the other with a weight of 40, are reporting a server106as available, the appliance may compute the sum of the monitoring agents currently reporting a server106as operational.

In some embodiments, the appliance200includes multiple types of monitoring agents. In one embodiment, a monitoring agent650may be a kernel based or kernel-mode agent. A kernel type monitor probes packets assembled within the kernel of the appliance. In one example, a kernel type monitors may be configures to perform a TCP-ECV (Extended Content Verification) to search for a string in an HTTP response, such as from a Web Interface. In another embodiment, the agent650may be a user mode based agent, referred to as an advanced monitor, user monitor or scriptable monitor. In some embodiments, an advanced monitors is a custom script that runs in user memory space on the appliance. An Advanced Monitor may be written in a number of programming languages, including Shell, Perl or Python. In some cases, the monitor is a binary executable instead of being written in an interpreted scripting language

The result of the test or probe of a monitoring agent may dictate a change in a state of the service275, e.g., UP/DOWN, to which the monitor is bound. In one embodiment, the monitoring agent returns a value of 0 to indicate success and a non-zero value to indicate an error or a failure. The kernel of the appliances may interpret the returned 0 value as a success, and anything other than zero as a failure. In response to the receiving the returned value from the monitoring agent, the appliance may mark the state of the service accordingly. In one embodiment, the appliance marks the service as FAILED when the value of the retries parameter is met. The appliance then moves the service or server out of load balancing, reducing the chance that users may experience problems getting to their applications.

The monitoring agent (monitor) may use one or more parameters to control monitoring behavior. In one embodiment, the monitor includes or uses an interval parameters. The interval may indicate the time in seconds between probes sent to a service. In another embodiment, the monitor includes a response timeout parameter to specify the amount of time the kernel of the appliance waits for the response from the monitor probe. In some embodiments, the monitor includes or uses a retires parameter which identifies the number of times the probe must fail before the kernel of the appliances marks the service as marked DOWN or otherwise unavailable. In yet another embodiment, the monitors includes or uses a downtime parameter which identifies an amount of time in seconds that the kernel of appliance may wait before initiating another probe after the service has been marked DOWN or unavailable.

In continued reference toFIG. 6A, when the user is successfully authenticated, the Access Gateway tunnel is initiated. The user is now prompted by the Access Gateway to permit the appropriate client software to be downloaded and installed. If the user is using the Access Gateway Plugin for Java, the client is also initialized with a list of preconfigured resource IP addresses and port numbers. When the user types the Access Gateway Web address, the Access Gateway checks to see if there are any client-based security policies. This is called a pre-authentication policy. If there are policies, it checks for the specified condition on the client device. These are generally security checks that verify that the client device has the necessary security-related operating system updates, antivirus protection, and perhaps a properly configured firewall. If the client device fails the security check, the Access Gateway blocks the user from logging on. A user unable to log on needs to download the necessary updates or packages and install them on the client device. After a user successfully logs on, the client device can be scanned for the required client security policies. This is called a post-authentication scan. If the client device fails the scan, either the policy is not applied or the user is placed in a quarantine group.

In some embodiments, configuring pre-authentication and post-authentication policies are optional. When the session is established, users are directed to an Access Gateway home page—a logon point—where they can select resources to access. The home page that is included with the Access Gateway is called the Access Interface. If the users log on using the Access Gateway Plugin for Windows, an icon in the notification area on Windows shows that it is connected and users receive a message that the connection is established. If the client's request passes both checks, the Access Gateway then contacts the requested resource and initiates a secure connection between the client and that resource.

The logon point defines the logon page for users and specifies settings that are applied to user sessions. These initial settings include the required authentication strength, the clients to use, the home page, and the accessible server farms. User sessions inherit the properties of the logon point through which they connect. The AAC controls which resources users can get to and what actions they can perform on those resources. With AAC, policies that have filters may be applied on user's session and activity, such as actions, based on information detected about the client device, who users are, the strength of their authentication, and where they are logging on. Filters provide the flexibility to match policies with user's access scenarios.

Policies extend the security of the network environment by controlling access and actions. AAC controls users' ability to connect to network resources based on meeting security requirements such as identity, authentication, antivirus, firewall, and client software. For resources accessed through the browser, AAC can control specific actions users perform based on the user scenario. Policies may be configures to provide connection privileges to trusted devices. When you create policies for the “Allow Logon” resource, you can deny connection privileges unless the client device meets your minimum security requirements verified through endpoint analysis scans. Connection policies may be used with continuous scans to monitor secure client connections throughout the user session, disconnecting as soon as the client device fails to meet requirements. After users pass security requirements for connecting, the user is granted explicit permission to a resource before the resource is available to the user. An administrator can control this access through policies defined for each resource or group of resources. By default, users may not be provided permission to access or take action on any resources on your networks.

In continued reference toFIG. 6A, the access gateway605may support two types of authentication: (i) Single Source Authentication and (ii) Two Source Authentication For single source authentication one password is required. For two source authentication, a secondary password also required. The access gateway605may support any type and form of authentications, such as any of the following.1. Radius Authentication2. LDAP authentication3. RSA Secure Id authentication4. Local authentication only5. Safe word authentication6. NTLM authentication
The access gateway605may have a server or service corresponding to each or any of the above authentication methods. An administration, in some embodiments, may run any server depending on the need of their authentication.

In some embodiments, a monitor650of the appliance200may probe for the health of the access gateway605. The administrator may create a local user and password as single source authentication for monitoring purpose. The access gateway605may provide or be configured with a password for the appliance200to be used by the monitor650.

In some embodiments, the monitor650internally behaves as a secure monitor. In some embodiments, to avoid exposing the monitor behavior, secure option of “add monitor” and “set monitor” is disabled for this monitor. In some embodiments, the following error will occur when trying to enable secure option.>add monitor agm Citrix-AG -userName user1-password citrix -secure YES ERROR: Arguments cannot both be specified [secure, type==CITRIX-AG]>add monitor agm citRIX-AG -userName user1-password citrix -secure NO ERROR: Arguments cannot both be specified [secure, type==CITRIX-AG]

When the access gateway605box is configured with any of the authentication means, the username supplied to the monitor may be realm/username. The realm may be required for single source or two source authentication.

In continued reference toFIG. 6A, in some embodiments, secure access management servers among the remote access servers602may host the authentication service620. The secure access management servers may be executing MetaFrame Secure Access Manager to authenticate the credentials, manufactured by Citrix Systems, Inc. of Fort Lauderdale, Fla. Further, any of the embodiments of the client102, appliance200, and/or servers described in reference toFIGS. 1A-5Cmay be deployed in system600. In some embodiments, the access gateway605may be the Citrix Access Gateway (AG) and/or Advanced Access Control (AAC) system manufactured by Citrix Systems, Inc. of Fort Lauderdale, Fla.

Referring now toFIG. 6B, a block diagram of an embodiment of an example response from a login mechanism of the access gateway is shown and described. In particular,FIG. 6Bdepicts an embodiment of a response to a request of the monitor650for a login page. The response may include any type of error or success codes. The response may include any one or more predetermined strings, text, numerics or name-value pairs inserted or otherwise provided by AAC or the server in response to the request. In some embodiments, the monitor650may consider a probe successful by identifying any combination of the following in the response:1. A HTTP response code of200OK is required2. The response code will contain _CTXMAX, _CTXVSC and _CTXVS0.

In some embodiments, the monitor identifies the presence of the predetermined string _CTXMAC and an HTTP response code of200to confirm a successful response. However, any of the response codes depicted inFIG. 6Bmay be an error or success code. Further, any combination of the response codes may indicate success. Some examples of possible success codes include a class of “CTXMSAM_ContentFont,” a form name of “pageForm,” and/or a hidden field of “_VIEWSTATE.”

Referring now toFIG. 6C, a block diagram of another embodiment of an example response from a login mechanism of the access gateway is shown and described. In particular, an embodiment of a response to a request of the monitor for the login agent service is depicted. The response may include any type of error or success codes. The response may include any one or more predetermined strings, text, numerics or name-value pairs inserted or otherwise provided by access gateway605or the server in response to the request. In some embodiments, the monitor may consider a probe successful by identifying any combination of a success code and any predetermined strings or name-value pairs. In one embodiments, the monitor may consider a probe successful by identifying an HTTP success code of200. As withFIG. 6B, any of the response codes depicted inFIG. 6Cor combinations thereof may be an error or success code. Some examples of possible success codes include an encoding of “utf-8,” a soap field of http://scemas.xmlsoap.org/soap/envelope, and/or an xsd field of “http://www.w3.org/2001/XMLSchema.”

Referring now toFIG. 7, a flow diagram depicting steps of an embodiment of a method for monitoring a status of a login page service of an access gateway to a plurality of remote access servers is shown and described. In brief overview, the method includes generating (step701) a request to access a login page service of the access gateway. The method further includes transmitting (step703) the generated request to the login page service of the access gateway. The method also includes determining (step705) whether a response from the login page service to the request identifies a successful response and at least one of a plurality of predetermined hidden fields. The method also includes identifying (step707) a status of the login page service as available or unavailable responsive to the determination.

Although the method is described as being performed with a single process, it should be understood that the method may be performed with any number of processes working sequentially and/or in parallel. For example, the monitor650of the appliance200may generate a plurality of requests to access one or more login page services610hosted by one or more access gateways605. The appliance200(also referred to herein as the “intermediary device”) may transmit generated requests to the login page services610at the same or different time. Further, the intermediary device200may determine whether a response from one login page service610identifies a successful response while determining whether the response from a different login page service610identifies a successful response.

In operation, a monitor650of an intermediary device200may generate a request to access a login page service610of the access gateway605(step501). The request may include any form or type of information directed to the login page service610. In particular, the request may include any combination of commands, values, parameters, and/or options that the login page service610may process. The request may include the logon point of the login page service610. The logon point may be identified through a URL. In some examples, the logon point may be a landing page supported by the access gateway605. The monitor650may specify the logon point of the request according to a configuration setting in the appliance200. In some embodiments, the appliance200may consult another device, such as a server or an appliance, for the logon point. In these embodiments, the appliance200may store the logon point in a cache.

In many embodiments, the request may identify the appliance200. For example, the request may identify the appliance200by including an IP address hosted by the appliance200, the product name of the appliance200, the appliance's MAC address, and/or the version of the appliance200. In various embodiments, the request may identify a user who is requesting authentication to access resources on the remote access servers602. In these embodiments, the request may include the user's credentials, such as a username and password. If the login page service610supports two source authentication, the request may also include a user's secondary password.

The monitor650may generate a request that includes user agent information for an agent on the appliance200. The user agent may be a web browser for accessing the login page service610, such as Mozilla or Internet Explorer.

Further, the request may use any type of protocol. For example, the request may be a TCP, UDP, FTP, or HTTP request. In some embodiments, the monitor650may generate a “TCP/ICMP echo request” or “UDP echo” command to send a datagram to the login page service610. In many embodiments, the monitor650may generate an FTP command (e.g., a “get” command or a “put” command) or an HTTP command (e.g., a “get” request for a uniform resource locator (URL) of the lm) of a logon point provided by the login page service610.

The monitor650may generate the request at a predetermined frequency, such as every 1 msec or 1 sec. In some embodiments, the monitor650may generate the request according to a schedule. In many embodiments, the monitor650may generate the request based upon detection of any type and form of event. For example, the monitor650may generate the request upon receipt of a request to access resources in the remote access servers602, such as a request for a web page, from a user at a client102. In some embodiments, the appliance200may store generated requests in a cache until the requests shall be transmitted to the login page service610.

In some embodiments, the monitor650may send a request to the access gateway605using a TCP connection with a completed SSL handshake. In one embodiment, the monitor may send the following request:GETVPNCONFIG/HTTP/1.0\r\nUser: $username\r\nPassword: $password\r\nx-quoted-passwd: “$password”\r\nSecondary-Password: “ ”\r\nx-app: win32client\r\nx-app-version: 457100\r\nMac: $Mac\r\n\r\n″

The request may be formed with any combination of commands, values, parameters and/or options understood or processable by the access gateway605. In some embodiments, the request may comprise any of the following arguments and values.

ArgumentValueUsernameSupplied in the CLIPasswordSupplied in the CLIx-quote-passedSame as PasswordSecondary-PasswordSupplied in the CLIMacAppliance Mac Valuex-appNetScaler or Product Name of Appliancex-app-versionVersion of Appliance

In some embodiments, one or more monitors are designed and constructed to monitor the Login Page of the access gateway605. The monitor may be configurable or designed to receive input to define the login point for the access gateway605. In some embodiments, the login point or login page comprises a URL or landing page supported or established via configuration of the access gateway605. In some embodiments, the monitor may send the following request to the configured access gateway605login page service:

After the monitor650generates the request, the intermediary device200may transmit the generated request to the login page service610of the access gateway650. The appliance200may transmit the request once the request is generated. In some embodiments, if the appliance200stores generated requests in a cache, the appliance200may retrieve a request from the cache to transmit to the login page service610.

After the intermediary device200transmits the generated request to the login page service610of the access gateway605, the monitor650may receive a response. From the response, the monitor may determine whether the response identifies at least one of a predetermined set of elements, such as a plurality of predetermined hidden fields. The monitor650determines the status of the login page service610as available or unavailable according to the predetermined hidden field(s) in the response. A predetermined hidden field may include strings, name-value pairs, numerics, any combination thereof, or the like. The monitor650may identify the login page service610as available if the response identifies at least one predetermined hidden field of a plurality thereof. The monitor650may require that the response identify any number of predetermined hidden fields to indicate that the login page service610is available. In some embodiments, the response may indentify two such fields.

In one example, the access gateway605may respond to a request from a monitor with a request as depicted inFIG. 6B. In another example, the access gateway605may respond to the monitor's request with a response with an embodiment of a format and structure as follows:

The monitor650may identify or use any one or more portions of the response to determine a status of the access gateway605. In some embodiments, an HTTP response code of200for the request is sufficient to qualify the monitor probe as a success. In another embodiment, the response code with one or more predetermined strings or name-value pairs qualifies the monitor probe as a success.

In some embodiments, the monitor may be configured or use as a configuration parameter to determine which one or more predetermined elements are required to be present as an indicator of a functional login mechanism. In some embodiments, the predetermined elements may be any elements of a form. In some embodiments, the predetermined elements may a field of a form. In some embodiments, the predetermined elements may hidden fields of a form as may be provided or transmitted by the login mechanism. In some embodiments, the predetermined element may a string, name or identifier of any value, element or content in the body of the response. In some embodiments, the predetermined element may be an expression or pattern to match a content of a body of the response.

In many embodiments, the response must identify one or more select predetermined hidden fields to indicate the login page service610is available. In these embodiments, if the response lacks any of such fields, the login page service610is deemed not functioning properly and identified as unavailable. In some embodiments, if a response does not include any of the plurality of predetermined hidden fields, the login page service610is deemed not functioning properly and identified as unavailable.

Referring now toFIG. 8, a flow diagram depicting steps of an embodiment of a method for monitoring by an intermediary device a status of a login agent of an access gateway to a plurality of remote access servers is shown and described. Although the steps are described in reference to a login agent, the present disclosure also encompasses other embodiments of the steps that monitor a DDC service on the access gateway. In brief overview, the method includes generating (step801) a post request to a logon agent of the access gateway, the post request identifying a logon point and a version of the logon agent. The method also includes transmitting (step803) the generated post request to the login agent of the access gateway. The method also includes determining (step805) whether the response from the logon agent to the request includes a predetermined string identifying a successful response. The method also includes identifying (step807) the status of the logon agent as available or unavailable responsive to the determination.

Although the method is described as being performed with a single process, it should be understood that the method may be performed with any number of processes working sequentially and/or in parallel. For example, a monitor650of an intermediary device200may generate a plurality of post requests to one or more logon agents610of one or more access gateways605. The intermediary device200may transmit the generated post requests to the logon agents610at the same or different time. Further, the intermediary device200may determine, in parallel, whether various logon agents610are available according to the responses the logon agents return.

In operation, a monitor605of an appliance200may generate a post request to a logon agent610of the access gateway605. The appliance200may be positioned between a plurality of clients102and an access gateway605to a plurality of remote access servers602. The request may include any form or type of information directed to the logon agent610of the access gateway605. In particular, the request may include any combination of commands, values, parameters, and/or options that the logon agent may process. The post request may identify the logon point of the logon agent610. The monitor650may specify the logon point of the post request according to a configuration setting in the appliance200. In some embodiments, the appliance200may consult another device, such as a server or an appliance, for the logon point. In these embodiments, the appliance200may store the logon point in a cache. The post request may also identify a version of the logon agent610. The appliance200may store the versions of logon agents610in a cache. In some embodiments, a third-party server may inform the appliance that versions of the logon agents have changed.

The post request may include any additional form or type of information directed to the logon agent610. In particular, the post request may include any combination of commands, values, parameters, and/or options that the logon agent610may process. In many embodiments, the post request may identify the appliance200. For example, the post request may identify the appliance200by including a source IP address routable to the appliance, the product name of the appliance, the appliance's MAC (Media Access Control) address, and/or the version of the appliance. The post request may also include any of the information for requests described in reference toFIG. 7.

In some embodiments, the request may comprise any of the following arguments and values.

Embodiment of Argumentsin XML requestEmbodiment of ValueLogonPointsupplied in the CLIUserAgentEMozilla/4.0 (compatible; MSIE 6.0; WindowsNT 5.0; .NET CLR 1.1.4322; .NET CLR2.0.50727)AcceptAny string (*)acceptLanguageEn-usgatewayMacAddressMac Value of Appliance 200baseUrlUsedByAgToMakeHttpRequestToLashttp://aacserviceip:80, Use https if AGAAC communication is secure. Monitormust be configured as Secure for this.https://aacserviceip:443 for secureconnection.externallyAddressableAddressOfAgMIP IP address of ApplianceVerson (V4.5 field)Supplied in the CLICookie ListNone

The post request may use any type of protocol. As described in reference toFIG. 7, the post request may be a TCP, UDP, FTP, or HTTP request. In many embodiments, the monitor650may generate an FTP command (e.g., a “put” command) or an HTTP command (e.g., a “push” request to the logon point).

In some embodiments, one or more monitors650on the appliance may be designed and constructed to monitor status of the logon agent service. In some embodiments, the monitor650may send the following request to the logon agent service:

In continued reference to step801, the monitor650may generate a post request for a DDC service on the access gateway605. In these embodiments, the DDC service may have a type of HTTP and may reside on the access gateway605. The DDC service may be created according to instructions such as:

add service xds 10.217.13.25 http 80

The appliance200may configure the monitor650to be of type CITRIX-XD-DDC and bind the monitor650to the DDC service. Configuring the monitor650and binding the monitor650to the DDC service may be accomplished through instructions such as:

add lb monitor xdm CITRIX-XD-DDC

bind lb monitor xdm xds

The post request for the DDC service may include any form or type of information directed to the DDC service. As for the request to the logon mechanism, the request may include any combination of commands, values, parameters, and/or options that the DDC service may process. In many embodiments, the post request may identify the appliance200.

For example, the post request may identify the appliance200by including a source IP address routable to the appliance, the product name of the appliance, the appliance's MAC (Media Access Control) address, and/or the version of the appliance. In various embodiments, the post request may include the type of content in the request, the XML version the request uses, and a request for data. In one example, the post request may include the following information:

The monitor650may generate the post request at a predetermined frequency, such as every 1 msec or 1 sec. In some embodiments, the monitor650may generate the post request according to a schedule. In many embodiments, the monitor650may generate the post request based upon detection of any type and form of event. For example, the monitor650may generate the post request upon receipt of a request to access resources in the remote access servers602, such as a request for a web page, from a user at a client102. In some embodiments, the appliance200may store generated post requests in a cache until the requests shall be transmitted to the logon agent.

After the monitor650generates the post request, the intermediary device200may transmit the generated post request to the logon agent610of the access gateway605. The appliance200may transmit the post request to a logon agent610once the request is generated. Alternatively, if the appliance200stores generated post requests in a cache, the appliance200may retrieve a post request from the cache to transmit to the logon agent610.

After the intermediary device200transmits the generated post request to the logon agent610, the monitor650may receive a response to the request from the logon agent610and determine if the response includes a predetermined string identifying a successful and/or functioning response. Such strings may include alphanumeric sequences, name-value pairs, any combination thereof, or the like. For example, strings like _CTXMAX, _CTXVSC, or _CTXVS0 may indicate success. In another example, an HTTP response code of200may indicate success. In some embodiments, the monitor650determines if the response has a combination of predetermined strings. For example, the monitor650may require the response include a string like “_CTXMAX” and an HTTP response code of200.

In some embodiments, the monitor650may apply a rule to determine if the response includes the predetermined string. An example of a rule may be that any response code with a predetermined prefix, such as “_CTX,” indicates a successful response. As a result, a monitor650may search a response for the predetermined prefix and indicate success or failure based on the results of the search. In more embodiments, the monitor650may attempt to match a response code with a group of response codes indicating success. For example, the appliance200may store response codes indicating success in an array. The monitor650may determine if the received response code matches any of the entries in the array. If the monitor650finds a match, the monitor650may determine that the response is successful.

The monitor650may determine if the response includes a predetermined string as a tag. If the monitor650detects the tag in the response, the monitor650may determine that the response is successful. Otherwise, a missing tag may indicate a failed response. For example, the monitor650may detect the tag “ServerFarmName” in the body of the following HTTP response to determine that the monitor was successful:

In some embodiments, the response must include the predetermined string within XML formatted values to be considered successful. In these embodiments, the string may be found in delimited fields. When the response does not include the string within XML formatted values, the response may be deemed unsuccessful. In these embodiments, the string may be missing from the response. In other embodiments, the response may include an improper value for the string.

In one example, the access gateway605may respond to a request from a monitor with a request as depicted inFIG. 6C. In this example, an HTTP response code of200indicates the response was successful.

After the monitor650determines if the response includes a predetermined string identifying a successful response, the monitor650may identify a status of the logon agent610or DDC service as available or unavailable. If the response includes the string, the logon agent610or service is available. Otherwise, the logon agent610or service is unavailable.

In view of the structure, functions and apparatus of the systems and methods described here, the present solution provides a dynamic, efficient and intelligent system for providing monitoring in a multi-core system. Having described certain embodiments of methods and systems for providing the monitoring in a multi-core system, it will now become apparent to one of skill in the art that other embodiments incorporating the concepts of the invention may be used. Therefore, the invention should not be limited to certain embodiments, but rather should be limited only by the spirit and scope of the following claims.