# Patent

## Title
Guaranteed delivery of application layer messages by a network element

## Abstract

A method is disclosed by which network elements such as packet routers and packet switches guarantee the delivery of application layer messages within a network. According to one aspect, a first network element retrieves an application layer message from a source message queue, adds a message identifier to the application layer message, encapsulates the application layer message into data packets, and sends the data packets toward a destination application. A second network element intercepts the data packets, determines the application layer message from payload portions of the data packets, determines the message identifier from the application layer message, stores the application layer message in a destination message queue, generates an acknowledgement message that contains the message identifier, and sends the acknowledgement message toward a source application. The first network element intercepts the acknowledgement message and concludes that the application layer message within the matching message identifier was successfully delivered.

## Background
FIELD OF THE INVENTION
The present invention generally relates to network elements in computer networks. The invention relates more specifically to a method and apparatus by which network elements guarantee the delivery of application layer messages within a network.
BACKGROUND
The approaches described in this section could be pursued, but are not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
In a business-to-business environment, applications executing on computers commonly communicate with other applications that execute on other computers. For example, an application “A” executing on a computer “X” might send, to an application “B” executing on a computer “Y,” a message that indicates the substance of a purchase order.
Computer “X” might be remote from computer “Y.” In order for computer “X” to send the message to computer “Y,” computer “X” might send the message through a computer network such as a local area network (LAN), a wide-area network (WAN), or an inter-network such as the Internet. In order to transmit the message through such a network, computer “X” might use a suite of communication protocols. For example, computer “X” might use a network layer protocol such as Internet Protocol (IP) in conjunction with a transport layer protocol such as Transport Control Protocol (TCP) to transmit the message.
Assuming that the message is transmitted using TCP, the message is encapsulated into one or more data packets; separate portions of the same message may be sent in separate packets. Continuing the above example, computer “X” sends the data packets through the network toward computer “Y.” One or more network elements intermediate to computer “X” and computer “Y” may receive the packets, determine a next “hop” for the packets, and send the packets towards computer “Y.”
For example, a router “U” might receive the packets from computer “X” and determine, based on the packets being destined for computer “Y,” that the packets should be forwarded to another router “V” (the next “hop” on the route). Router “V” might receive the packets from router “U” and send the packets on to computer “Y.” At computer “Y,” the contents of the packets may be extracted and reassembled to form the original message, which may be provided to application “B.” Applications “A” and “B” may remain oblivious to the fact that the packets were routed through routers “U” and “V.” Indeed, separate packets may take different routes through the network.
A message may be transmitted using any of several application layer protocols in conjunction with the network layer and transport layer protocols discussed above. For example, application “A” may specify that computer “X” is to send a message using Hypertext Transfer Protocol (HTTP). Accordingly, computer “X” may add HTTP-specific headers to the front of the message before encapsulating the message into TCP packets as described above. If application “B” is configured to receive messages according to HTTP, then computer “Y” may use the HTTP-specific headers to handle the message.
In addition to all of the above, a message may be structured according to any of several message formats. A message format generally indicates the structure of a message. For example, if a purchase order comprises an address and a delivery date, the address and delivery date may be distinguished from each other within the message using message format-specific mechanisms. For example, application “A” may indicate the structure of a purchase order using Extensible Markup Language (XML). Using XML as the message format, the address might be enclosed within “<address>” and “</address>” tags, and the delivery date might be enclosed within “<delivery-date>” and “</delivery-date>” tags. If application “B” is configured to interpret messages in XML, then application “B” may use the tags in order to determine which part of the message contains the address and which part of the message contains the delivery date.
As is discussed above, a message may be divided into portions, and each portion may be transmitted in a separate IP packet toward the message's destination. The TCP protocol implements mechanisms for ensuring that IP packets may be assembled in their proper order relative to each other, and that no IP packet will be duplicated.
When a destination application (e.g., application “B” in the example above) receives a TCP packet, the destination application sends an acknowledgment back toward the packet's source. The acknowledgement identifies the packet by the packet's sequence number. If the source application (e.g., application “A” in the example above) receives the acknowledgement within a specified interval of time after sending the corresponding packet, then the source application will be confident that the destination application received the packet. As a result, the source application does not need to re-send the packet. Alternatively, if the source application does not receive the acknowledgement within a specified interval of time after sending the corresponding packet, then the source application re-sends the packet. The packet may be re-sent until the source application receives an acknowledgment.
Under some circumstances, a proxy device receives packets from a source application and then forwards the packets to the destination application. Under these circumstances, the proxy device sends acknowledgements back to the source application. It is possible that the proxy device might send an acknowledgment to the source application, but the packet corresponding to the acknowledgment might not successfully reach the destination application. For example, this might happen if the connection between the proxy device and the destination application is broken, or if the destination application fails. Under these circumstances, the source application still will receive the acknowledgement from the proxy device and, consequently, will not re-send the packet even though the packet never reached the destination application.
Thus, under some circumstances, such as those described above, the TCP protocol does not guarantee that a particular TCP packet actually will reach a destination application. As a result, there is no guarantee that a message at least partially contained within the particular TCP packet will reach the destination application.
A technique for guaranteeing that a message sent from a source application will be received by a destination application is needed.



BRIEF DESCRIPTION OF THE DRAWINGS
The present invention is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar elements and in which:
FIG. 1 is a block diagram that illustrates an overview of one embodiment of a system in which network elements collectively guarantee the delivery of application layer messages;
FIG. 2A depicts a flow diagram that illustrates an overview of one embodiment of a method of reliably sending messages using a message queue and message identifiers contained within application layer messages;
FIG. 2B depicts a flow diagram that illustrates an overview of one embodiment of a method of guaranteeing message delivery using a message queue and message identifiers contained within acknowledgement messages;
FIGS. 3A-B depict a flow diagram that illustrates one embodiment of a method of classifying application layer messages into message classifications and performing actions that are associated with those message classifications;
FIG. 4 depicts a sample flow that might be associated with a particular message classification;
FIG. 5 is a block diagram that illustrates a computer system upon which an embodiment may be implemented;
FIG. 6 is a block diagram that illustrates one embodiment of a router in which a supervisor blade directs some packet flows to an AONS blade and/or other blades;
FIG. 7 is a diagram that illustrates the various components involved in an AONS network according to one embodiment;
FIG. 8 is a block diagram that depicts functional modules within an example AONS node;
FIG. 9 is a diagram that shows multiple tiers of filtering that may be performed on message traffic in order to produce only a select set of traffic that will be processed at the AONS layer;
FIG. 10 is a diagram that illustrates the path of a message within an AONS cloud according to a cloud view;
FIG. 11A and FIG. 11B are diagrams that illustrate a request/response message flow;
FIG. 12A and FIG. 12B are diagrams that illustrate alternative request/response message flows;
FIG. 13 is a diagram that illustrates a one-way message flow;
FIG. 14 is a diagram that illustrates alternative one-way message flows;
FIG. 15A and FIG. 15B are diagrams that illustrate a request/response message flow with reliable message delivery;
FIG. 16 is a diagram that illustrates a one-way message flow with reliable message delivery;
FIG. 17 is a diagram that illustrates synchronous request and response messages;
FIG. 18 is a diagram that illustrates a sample one-way end-to-end message flow;
FIG. 19 is a diagram that illustrates message-processing modules within an AONS node;
FIG. 20 is a diagram that illustrates message processing within AONS node;
FIG. 21, FIG. 22, and FIG. 23 are diagrams that illustrate entities within an AONS configuration and management framework; and
FIG. 24 is a diagram that illustrates an AONS monitoring architecture.



DETAILED DESCRIPTION
A method and apparatus for reducing the sizes of application layer messages in a network element is described. In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to avoid unnecessarily obscuring the present invention.
Embodiments are described herein according to the following outline:

    
    
        1.0 General Overview
        2.0 Structural and Functional Overview
        3.0 Implementation Examples
        
            3.1 Multi-Blade Architecture
            3.2 Message Classification
            3.3 Action Flows
            3.4 AONS Examples
            
                3.4.1 AONS General Overview
                3.4.2 AONS Terminology
                3.4.3 AONS Functional Overview
                3.4.4 AONS System Overview
                3.4.5 AONS System Elements
                3.4.6 AONS Example Features
                3.4.7 AONS Functional Modules
                3.4.8 AONS Modes of Operation
                3.4.9 AONS Message Routing
                3.4.10 Flows, BladeletsTM, and ScriptletsTM
                3.4.11 AONS Services
                3.4.12 AONS Configuration and Management
                3.4.13 AONS Monitoring
                3.4.14 AONS Tools
            
            
        
        
        4.0 Implementation Mechanisms—Hardware Overview
        5.0 Extensions and Alternatives

1.0 General Overview

    
    


The needs identified in the foregoing Background, and other needs and objects that will become apparent for the following description, are achieved in the present invention, which, in one aspect, comprises a system in which network elements guarantee that application layer messages will be delivered. As used herein, an “application layer message” is a message that is generated by an application—although the message may also contain content supplied by one or more users—and which does not necessarily include the protocol headers that may be appended in the course of the transmission of that message. For example, an application layer message may be an XML document that does not include an HTTP header that is later appended to the front of that document.
According to one embodiment, a source application inserts a first application layer message into a source message queue in a transactional manner; this guarantees that the first application layer message will be inserted into the source message queue. A first network element that acts as the network's entry node, such as a network switch, router, proxy device, network appliance and/or a device that is attached or connected to a switch or router and that performs OSI Layer 2 and above processing, including packet- and message-level processing, proactively retrieves the first application layer message from the source message queue without removing the first application layer message from the source message queue. To the first application layer message, the first network element generates a universally unique message identifier and adds that to the first application layer message. The first network element establishes a mapping between the message identifier and the first application layer message. The first network element then encapsulates the first application layer message into data packets, such as IP packets, and sends the data packets toward a destination application.
A second network element, such as a network switch, router, or proxy device, which acts as the exit point of the network, is sitting between the network route and the destination application, intercepts or otherwise receives the data packets. The second network element determines the first application layer message, which is collectively contained in payload portions of the data packets. The second network element determines the message identifier, which is contained in the first application layer message. The second network element determines whether the message identifier is already contained in a message identifier queue. If the message identifier is already contained in the message identifier queue, then the second network element drops the first application layer message so that the first application layer message is not delivered to the destination application; this prevents duplicate messages from being delivered to the destination application.
Alternatively, if the message identifier is not already contained in the message identifier queue, then the second network element inserts the message identifier into the message identifier queue and inserts the first application layer message into a destination message queue in a transactional manner; this guarantees that the first application layer message will be inserted into the destination message queue. In some embodiments, in response to a determination that the message identifier queue does not contain the message identifier, the message identifier is stored in the message identifier queue, together with the storing of the first application message in the application layer message queue atomically. The second network element also generates a second application message (which we call ACK message later on) that acknowledges receipt of the first application layer message. The second application layer message (ACK message) contains the message identifier of the first application message. The second network element then encapsulates the ACK message into data packets, such as IP packets, and sends the data packets towards the first network element.
The destination application proactively retrieves the first application layer message from the destination message queue in a transactional manner. After the destination application has retrieved the first application layer message from the destination message queue, the destination application removes the first application layer message from the destination message queue.
If the first network element, which sits in the network route to the source application, intercepts or otherwise receives the data packets sent from the second network element, then the first network element determines the ACK message, which is collectively contained in payload portions of the data packets. The first network element extracts the message identifier from the ACK message. From the source message queue, the first network element removes the first application layer message, which is mapped to the message identifier. The successful delivery of the first application layer message has been guaranteed.
Alternatively, if a specified amount of time passes after the first network element sent the first application layer message without the first network element receiving the data packets sent from the second network element, then the first network element concludes that the first application layer message needs to be re-sent. The first network element re-sends the first application layer message, including the message identifier, toward the destination application in the same manner as described above. Unless some problem permanently prevents the delivery of the first application layer message, the first network element eventually will receive the ACK message from the second network element.
In other aspects, the invention encompasses methods performed by the first and second network elements in the foregoing system, and computer-readable media configured to carry out the steps of such methods.
2.0 Structural and Functional Overview
FIG. 1 is a block diagram that illustrates an overview of one embodiment of a system 100 in which one or more of network elements 102 and 106 collectively guarantee the delivery of application layer messages (also referred to herein simply as “messages”). Network elements 102 and 106 may be proxy devices or network switches or routers, for example. Network elements 102 and 106 may be network routers such as router 600 depicted in FIG. 6 below, for example.
A client application 110 is coupled communicatively to persistent storage 136. Persistent storage 136 is coupled communicatively with network element 102. Persistent storage 136 may be incorporated into a device that is separate from network element 102.
A server application 112 is coupled communicatively to persistent storage 138. Persistent storage 138 is communicatively coupled with network element 106. Persistent storage 138 may be incorporated into a device that is separate from network element 106. Client application 110 and server application 112 are separate processes executing on separate computers.
Network elements 102 and 106 are coupled communicatively with a network 116. Network 116 is a computer network, such as, for example, a local area network (LAN), wide area network (WAN), or internetwork such as the Internet. Network 116 may contain additional network elements such as routers.
Persistent storage 136 and persistent storage 138 are repositories that persistently store data. Persistent storage 136 and persistent storage 138 may be hard disk drives of devices that are separate from network elements 102 and 106, for example. Persistent storage 136 and persistent storage 138 may comprise databases that organize the data stored thereon in a relational manner. Such databases may allow data to be stored in a transactional manner, so that either all data belonging to a particular transaction is committed, or no data belonging to the particular transaction is committed.
Transactional message queues 130 and 134 are used to guarantee end-to-end delivery. Client application 110 (the “sender application”) addresses messages to server application 112 and inserts the messages into a source message queue 130 that is located on persistent storage 136. Thus, client application 110 “pushes” messages into source message queue 130 by enqueueing the messages. Messages may be XML documents, Java Messaging Service (JMS) messages, or other kinds of messages, for example. After client application 110 has pushed a message into source message queue 130, client application 110 commits, into a client-side database, a transaction with which the message is associated. Network element 102 (the “client proxy” or “CP”) proactively retrieves messages from source message queue 130 by transactionally dequeueing the messages, inserts message identifiers into those messages, and sends those messages within data packets toward server application 112 (the “receiver application”). Thus, network element 102 “pulls” messages from source message queue 130 and sends the messages through network 116.
Network element 106 (the “server proxy” or “SP”) intercepts the data packets that contain the messages. For each set of one or more data packets that contains a separate message, network element 106 assembles the data packets in that set to determine the message contained therein. For each such message, network element 106 determines whether the message's identifier is already contained in a message identifier queue 132 that is located on persistent storage 138. If the message's identifier is already contained in message identifier queue 132, then network element 106 does not store the message in a destination message queue 134 that is located on persistent storage 138. However, if the message's identifier is not contained in message identifier queue 132, then network element 106 stores the message's identifier in message identifier queue 132 and stores the message itself in destination message queue 134. Thus, network element 106 “pushes” the message into destination message queue 134 by enqueueing the message and “pushes” the message's identifier into message identifier queue 132. After network element 106 has pushed the message and message identifier in this manner, client application 110 commits, into a server-side database, a transaction with which the message is associated.
After network element 106 has successfully pushed the message into destination message queue 134, network element 106 generates an acknowledgement message (ACK) that contains the message's identifier. Network element 106 sends the ACK within data packets toward network element 102.
Network element 102 intercepts the data packets that contain the ACK. Network element 102 determines the message identifier that is contained in the ACK. Network element 102 commits, into a client-side database, a transaction with which the message is associated. Network element 102 removes, from source message queue 130, the message that corresponds to the message identifier. Because the message is removed from source message queue 130, network element 102 will not re-send the message thereafter.
Based on the contents of the message, network element 106 may determine a classification for the message and perform one or more actions that are associated with the message's classification. Examples of some of these actions are described in further detail below with reference to FIGS. 3A-3B. Server application 112 (the “receiver application”) proactively retrieves messages from destination message queue 134 by dequeueing the messages. Server application 112 commits, into a server-side database, a transaction with which the message is associated. Server application 112 removes such retrieved messages from destination message queue 134.
Each message in source message queue 130 may be associated with a time at which that message was most recently sent (the “message's sending time”). For each message remaining in source message queue 130, when a specified amount of time passes since the message's sending time, network element 102 re-sends the message and updates the message's sending time. Network element 102 periodically re-sends messages remaining in source message queue 130 until network element 102 receives corresponding acknowledgement messages that indicate the corresponding message identifiers.
FIG. 2A depicts a flow diagram 200A that illustrates an overview of one embodiment of a method of reliably sending messages using a message queue and message identifiers contained within application layer messages. For example, network element 102 may perform such a method.
In block 202, a network element retrieves an application layer message from a message queue. For example, network element 102 may retrieve an application layer message from source message queue 130. The application layer message may be an XML document or a JMS message, for example. The application layer message might indicate the substance of a purchase order, for example. Network element 102 may periodically poll source message queue 130 for messages that have not yet been sent, and retrieve those messages.
In block 204, a message identifier is added to the application layer message. For example, network element 102 may add, to the application layer message retrieved from source message queue 130, a number that uniquely identifies the application layer message. For example, if the message is an XML document, then network element 102 may add, to the XML document, an XML element such as “<message ID=‘123’>”. The message identifier is contained within the message itself, rather than in a protocol header that precedes the message. In one embodiment, the number is added to the copy of the message that is stored in source message queue 130, so that if the message is re-sent, the message will be re-sent with the same message identifier.
In block 206, the application layer message is sent toward a destination application. For example, network element 102 may encapsulate the application layer message into one or more TCP packets and send the packets toward server application 112. In one embodiment, each message in source message queue 130 is associated with an indication of the message's ultimate destination. For example, each message may be associated with a separate destination IP address, and network element 102 may send each message toward the destination IP address that is associated with that message.
In block 208, it is determined whether at least a specified amount of time has passed since the application layer message was sent. For example, when network element 102 sends an application layer message, network element 102 may associate the application layer message with a timestamp within source message queue 130. Network element 102 may determine whether a specified amount of time has elapsed since a particular message was sent by comparing the message's associated timestamp with the current time. If at least the specified amount of time has elapsed, then control passes to block 206, in which the application layer message is re-sent toward the destination application. Otherwise, control passes to block 210.
In block 210, it is determined whether an acknowledgement message that contains the message identifier has been received. For example, network element 102 may receive one or more data packets that collectively contain, in their payload portions, an acknowledgement message that contains a message identifier. Such an acknowledgement message may be generated by network element 106, for example, as is described below with reference to FIG. 2B.
Network element 102 may assemble the data packets to determine the acknowledgement message and the message identifier contained therein. Network element 102 is capable of determining application layer message boundaries, so, in one embodiment, network element 102 may perform operations on an application layer message contained in a stream, or portions thereof, even if network element 102 has not yet received all of the data packets that contain all of the portions of the application layer message. For example, an acknowledgement message might be an XML document that contains an XML element such as “<acknowledgement ID=‘123’>”. Network element 102 may compare the acknowledgement message's identifier with the application layer message's identifier. If there is a match, then network element 102 may conclude that the acknowledgement message that corresponds to the application layer message has been received. In this case, control passes to block 212. Otherwise, if the acknowledgement message that corresponds to the application layer message has not yet been received, then control passes back to block 208.
In block 212, the application layer message is removed from the message queue. For example, network element 102 may remove the application layer message from source message queue 130. The receipt of the acknowledgement message that contains the application layer message's identifier signifies that the message has been delivered reliably. Thereafter, due to the removal of the application layer message from source message queue 130, network element 102 will not re-send the application layer message.
FIG. 2B depicts a flow diagram 200B that illustrates an overview of one embodiment of a method of guaranteeing message delivery using a message queue and message identifiers contained within acknowledgement messages. For example, network element 106 may perform such a method.
In block 220, data packets are intercepted or otherwise received by a network element. For example, network element 106 may intercept one or more TCP data packets that were sent toward server application 112 by network element 102.
In block 222, an application layer message is determined from payload portions of the data packets. For example, network element 106 may assemble the data packets that are destined for server application 112. Network element 106 may inspect the contents of the payload portions of the assembled data packets to determine an application layer message that client application 110 is trying to send to server application 112. The message may be, for example, a purchase order formatted according to XML. The message might follow an HTTP header, for example.
In block 224, a message identifier is determined from the application layer message. For example, network element 106 may look within the application layer message for a specified XML element that indicates a message identifier. The message identifier is contained within the application layer message itself, rather than a protocol header that precedes the application layer message. For example, network element 106 might find, within the application layer message, an XML element such as “<message ID=‘123’>” that network element 102 added to the message. In this case, the message identifier is “123”.
In block 226, it is determined whether the message identifier is contained in a message identifier queue. For example, network element 106 may query message identifier queue 132 to determine whether message identifier queue 132 contains the message identifier. If the message identifier queue contains the message identifier, then control passes to block 228. Otherwise, control passes to block 230.
In block 228, the application layer message is dropped. The application layer message is not stored in a destination message queue as described below with reference to block 230. The presence of the message identifier within message identifier queue 132 signifies that the application layer message duplicates a message that has already been delivered; such duplicates may occur when an acknowledgement message fails to reach a “sending” network element in a timely manner, causing the sending network element to re-send a message. Because the message is a duplicate, the message should not be stored in destination message queue 134, where the message would be retrieved by server application 112. Control passes to block 234.
Alternatively, in block 230, the application layer message is inserted into a message queue. For example, network element 106 may insert the application layer message into destination message queue 134. Server application 112 may proactively retrieve the application layer message from destination message queue 134. Control passes to block 232.
In block 232, the message identifier is inserted into a message identifier queue. For example, network element 106 may insert the message identifier into message identifier queue 132. This prevents duplicate application layer messages with the same message identifier from being inserted into destination message queue 134. Control passes to block 234.
In block 234, an acknowledgement application layer message (“acknowledgement message”) is generated and sent toward the source application from which the original application layer message originated. The acknowledgement message contains the message identifier that was contained in the corresponding application layer message. For example, network element 106 may generate an acknowledgement message that contains an XML element such as “<acknowledgement ID=‘123’>”, assuming that the corresponding application layer message indicated a message identifier of “123”. Network element 106 may encapsulate the acknowledgement message within one or more TCP packets, and send the TCP packets toward client application 110.
Although, in one embodiment, data packets that contain application layer messages are addressed to client application 110 and server application 112, in an alternative embodiment, such data packets are addressed to network element 102 and network element 106. This may be the case when network element 102 and network element 106 are both proxy devices, for example.
Techniques are described above in relation to application layer messages sent from client application 110 toward server application 112. The above techniques are also applicable to application layer message sent from server application 112 toward client application 110. For example, the techniques described above may be used to guarantee the delivery of requests from client application 110 to server application 112, and to guarantee the delivery of corresponding responses from server application 112 to client application 110.
3.0 Implementation Examples
3.1 Multi-Blade Architecture
According to one embodiment, an Application-Oriented Network Services (AONS) blade in a router performs the actions discussed above. FIG. 6 is a block diagram that illustrates one embodiment of a router 600 in which a supervisor blade 602 directs some of packet flows 610A-B to an AONS blade and/or other blades 606N. Router 600 comprises supervisor blade 602, AONS blade 604, and other blades 606A-N. Each of blades 602, 604, and 606A-N is a single circuit board populated with components such as processors, memory, and network connections that are usually found on multiple boards. Blades 602, 604, and 606A-N are designed to be addable to and removable from router 600. The functionality of router 600 is determined by the functionality of the blades therein. Adding blades to router 600 can augment the functionality of router 600, but router 600 can provide a lesser degree of functionality with fewer blades at a lesser cost if desired. One of more of the blades may be optional.
Router 600 receives packet flows such as packet flows 610A-B. More specifically, packet flows 610A-B received by router 600 are received by supervisor blade 602. Supervisor blade 602 may comprise a forwarding engine and/or a route processor such as those commercially available from Cisco Systems, Inc.
In one embodiment, supervisor blade 602 classifies packet flows 610A-B based on one or more parameters contained in the packet headers of those packet flows. If the parameters contained in the packet header of a particular packet match specified parameters, then supervisor blade 602 sends the packets to a specified one of AONS blade 604 and/or other blades 606A-N. Alternatively, if the parameters contained in the packet header do not match any specified parameters, then supervisor blade 602 performs routing functions relative to the particular packet and forwards the particular packet on toward the particular packet's destination.
For example, supervisor blade 602 may determine that packet headers in packet flow 610B match specified parameters. Consequently, supervisor blade 602 may send packets in packet flow 610B to AONS blade 604. Supervisor blade 602 may receive packets back from AONS blade 604 and/or other blades 606A-N and send the packets on to the next hop in a network path that leads to those packets' destination. For another example, supervisor blade 602 may determine that packet headers in packet flow 610A do not match any specified parameters. Consequently, without sending any packets in packet flow 610A to AONS blade 604 or other blades 606A-N, supervisor blade 602 may send packets in packet flow 610A on to the next hop in a network path that leads to those packets' destination.
AONS blade 604 and other blades 606A-N receive packets from supervisor blade 602, perform operations relative to the packets, and return the packets to supervisor blade 602. Supervisor blade 602 may send packets to and receive packets from multiple blades before sending those packets out of router 600. For example, supervisor blade 602 may send a particular group of packets to other blade 606A. Other blade 606A may perform firewall functions relative to the packets and send the packets back to supervisor blade 602. Supervisor blade 602 may receive the packet from other blade 606A and send the packets to AONS blade 604. AONS blade 604 may perform one or more message payload-based operations relative to the packets and send the packets back to supervisor blade 602.
According to one embodiment, the following events occur at an AONS router such as router 600. First, packets, containing messages from clients to servers, are received. Next, access control list-based filtering is performed on the packets and some of the packets are sent to an AONS blade or module. Next, TCP termination is performed on the packets. Next, Secure Sockets Layer (SSL) termination is performed on the packets if necessary. Next, Universal Resource Locator (URL)-based filtering is performed on the packets. Next, message header-based and message content-based filtering is performed on the packets. Next, the messages contained in the packets are classified into AONS message types. Next, a policy flow that corresponds to the AONS message type is selected. Next, the selected policy flow is executed. Then the packets are either forwarded, redirected, dropped, copied, or fanned-out as specified by the selected policy flow.
3.2 Message Classification
FIGS. 3A-B depict a flow diagram 300 that illustrates one embodiment of a method of classifying application layer messages into message classifications and performing actions that are associated with those message classifications. For example, one or more of network elements 102 and 106 may perform such a method. More specifically, AONS blade 604 may perform one or more steps of such a method. Other embodiments may omit one or more of the operations depicted in flow diagram 300. Other embodiments may contain operations additional to the operation depicted in flow diagram 300. Other embodiments may perform the operations depicted in flow diagram 300 in an order that differs from the order depicted in flow diagram 300.
Referring first to FIG. 3A, in block 302, user-specified input is received at a network element. The user-specified input indicates the following: one or more criteria that are to be associated with a particular message classification, and one or more actions that are to be associated with the particular message classification. The user-specified input may indicate an order in which the one or more actions are to be performed. The user-specified input may indicate that outputs of actions are to be supplied as inputs to other actions. For example, network element 102, and more specifically AONS blade 604, may receive such user-specified input from a network administrator.
In block 304, an association is established, at the network element, between the particular message classification and the one or more criteria. For example, AONS blade 604 may establish an association between a particular message classification and one or more criteria. For example, the criteria may indicate a particular string of text that a message needs to contain in order for the message to belong to the associated message classification. For another example, the criteria may indicate a particular path that needs to exist in the hierarchical structure of an XML-formatted message in order for the message to belong to the associated message classification. For another example, the criteria may indicate one or more source IP addresses and/or destination IP addresses from or to which a message needs to be addressed in order for the message to belong to the associated message classification.
In block 306, an association is established, at the network element, between the particular message classification and the one or more actions. One or more actions that are associated with a particular message classification comprise a “policy” that is associated with that particular message classification. A policy may comprise a “flow” of one or more actions that are ordered according to a particular order specified in the user-specified input, and/or one or more other actions that are not ordered. For example, AONS blade 604 may establish an association between a particular message classification and one or more actions. Collectively, the operations of blocks 302-306 comprise “provisioning” the network element.
In block 308, one or more data packets that are destined for a device other than the network element are intercepted by the network element. The data packets may be, for example, data packets that contain IP and TCP headers. The IP addresses indicated in the IP headers of the data packets differ from the network element's IP address; thus, the data packets are destined for a device other than the network element. For example, network element 102, and more specifically, supervisor blade 602, may intercept data packets that client application 110 originally sent. The data packets might be destined for server application 112, for example.
In block 310, based on one or more information items indicated in the headers of the data packets, an application layer protocol that was used to transmit a message contained in the payload portions of the data packets (hereinafter “the message”) is determined. The information items may include, for example, a source IP address in an IP header, a destination IP address in an IP header, a TCP source port in a TCP header, and a TCP destination port in a TCP header. For example, network element 102, and more specifically AONS blade 604, may store mapping information that maps FTP (an application layer protocol) to a first combination of IP addresses and/or TCP ports, and that maps HTTP (another application layer protocol) to a second combination of IP addresses and/or TCP ports. Based on this mapping information and the IP addresses and/or TCP ports indicated by the intercepted data packets, AONS blade 604 may determine which application layer protocol (FTP, HTTP, Simple Mail Transfer Protocol (SMTP), etc.) was used to transmit the message.
In block 312, a message termination technique that is associated with the application layer protocol used to transmit the message is determined. For example, AONS blade 604 may store mapping information that maps FTP to a first procedure, that maps HTTP to a second procedure, and that maps SMTP to a third procedure. The first procedure may employ a first message termination technique that can be used to extract, from the data packets, a message that was transmitted using FTP. The second procedure may employ a second message termination technique that can be used to extract, from the data packets, a message that was transmitted using HTTP. The third procedure may employ a third message termination technique that can be used to extract, from the data packets, a message that was transmitted using SMTP. Based on this mapping information and the application layer protocol used to transmit the message, AONS blade 604 may determine which procedure should be called to extract the message from the data packets.
In block 314, the contents of the message are determined based on the termination technique that is associated with the application layer protocol that was used to transmit the message. For example, AONS blade 604 may provide the data packets as input to a procedure that is mapped to the application layer protocol determined in block 312. The procedure may use the appropriate message termination technique to extract the contents of the message from the data packets. The procedure may return the message as output to AONS blade 604. Thus, in one embodiment, the message extracted from the data packets is independent of the application layer protocol that was used to transmit the message.
In block 316, a message classification that is associated with criteria that the message satisfies is determined. For example, AONS blade 604 may store mapping information that maps different criteria to different message classifications. The mapping information indicates, among possibly many different associations, the association established in block 304. AONS blade 604 may determine whether the contents of the message satisfy criteria associated with any of the known message classifications. In one embodiment, if the contents of the message satisfy the criteria associated with a particular message classification, then it is determined that the message belongs to the particular message classification.
Although, in one embodiment, the contents of the message are used to determine a message's classification, in alternative embodiments, information beyond that contained in the message may be used to determine the message's classification. For example, in one embodiment, a combination of the contents of the message and one or more IP addresses and/or TCP ports indicated in the data packets that contain the message is used to determine the message's classification. For another example, in one embodiment, one or more IP addresses and/or TCP ports indicated in the data packets that contain the message are used to determine the message's classification, regardless of the contents of the message.
In block 318, one or more actions that are associated with the message classification determined in block 316 are performed. If two or more of the actions are associated with a specified order of performance, as indicated by the user-specified input, then those actions are performed in the specified order. If the output of any of the actions is supposed to be provided as input to any of the actions, as indicated by the user-specified input, then the output of the specified action is provided as input to the other specified action.
A variety of different actions may be performed relative to the message. For example, an action might indicate that a message is to be reliably delivered. In this case, a unique message identifier may be inserted into the body of the message before the message is forwarded out of the network element.
For another example, an action might indicate that the message is to be dropped. In this case, the message is prevented from being forwarded out of the network element toward that message's destination. For another example, an action might indicate that a message is to be compressed using a specified compression technique before being forwarded out of the network element.
For another example, an action might indicate that the content of the message is to be altered in a specified manner. For example, an action might indicate that specified text is to be inserted into a specified location in the message. Such a location might be specified by a path in an XML hierarchical structure of the message, for example, or by a specified string of text occurring in the message. For another example, an action might indicate that specified text is to be deleted from the message. For another example, an action might indicate that specified text is to be substituted for other specified text in the message. Text inserted into the message might be obtained dynamically (“on the fly”) from a database that is external to the network element.
For another example, an action might indicate that the message format of a message is to be altered in a specified manner. For example, an action might indicate that a message's format is to be changed from XML to some other format such as EDI. For another example, an action might indicate that a message's format is to be changed from some format other than XML into XML. The message format may be altered without altering the core content of the message, which is independent of the message format.
For another example, an action might indicate that the message is to be forwarded using a specified application layer protocol other than the application layer protocol that the message's origin used to transmit the message. For example, client application 110 might have used a first application layer protocol, such as HTTP, to transmit the message. Thus, when intercepted by network element 102, the message might have contained an HTTP header. However, in accordance with a specified action, before network element 102 forwards the message towards the message's destination, network element 102, and more specifically AONS blade 604, may modify the message so that the message will be carried using an application layer protocol other than HTTP (such as FTP, SMTP, etc.).
For another example, an action might indicate that the message's destination is to be altered so that the message will be forwarded towards a device that is different from the device that the message's source originally specified. For example, in accordance with a specified action, network element 102, and more specifically AONS blade 604, might encapsulate the message in one or more new IP data packets that indicate a new destination IP address that differs from the destination IP address that the originally intercepted IP data packets indicated. Network element 102 may then forward the new IP data packets toward the new destination. In this manner, message content-based routing may be achieved.
For another example, an action might indicate that a specified event is to be written into a specified log that might be external to the network element. For example, in accordance with a specified action, network element 102, and more specifically AONS blade 604, might write at least a portion of the message, along with the IP address from which the message was received, to a log file.
For another example, an action might indicate that the message is to be encrypted using a specified key before being forwarded to a destination. For example, in accordance with a specified action, network element 102, and more specifically AONS blade 604, might encrypt at least a portion of the message using a specified key and then forward data packets that contain the encrypted message towards the message's destination.
For another example, an action might indicate that a response cached at the network element is to be returned to the device from which the message originated, if such a response is cached at the network element. For example, network element 102, and more specifically AONS blade 604, may determine whether a response to the message is cached at network element 102; such a response might have be cached at network element 102 at the time a previous response to the same message passed through network element 102. If network element 102 determines that such a response is cached, then network element 102 may return the response to the message's origin. Consequently, network element 102 does not need to forward the message to the message's destination, and the message's destination does not need to issue another response to the message.
If the message was modified in some way (e.g., content, format, or protocol modification) during the performance of the actions, and if the modified message is supposed to be forwarded out of the network element, then the network element encapsulates the modified message into new data packets and sends the new data packets towards the modified message's destination—which also might have been modified.
A message might not belong to any known message classification. In this case, according to one embodiment, the network element does not perform any user-specified actions relative to the message. Instead, the network element simply forwards the data packets to the next hop along the path to the data packets' indicated destination.
As a result of the method illustrated in flow diagram 300, applications such as client application 110 and server application 112 can communicate with each other reliably and as though no network elements acted as intermediaries, and as though each other application communicated using the same message format and application layer protocol.
3.3 Action Flows
FIG. 4 depicts a sample flow 400 that might be associated with a particular message classification. Flow 400 comprises, in order, actions 402-414; other flows may comprise one or more other actions. Action 402 indicates that the content of the message should be modified in a specified manner. Action 404 indicates that a specified event should be written to a specified log. Action 406 indicates that the message's destination should be changed to a specified destination. Action 408 indicates that the message's format should be translated into a specified message format. Action 410 indicates that the application layer protocol used to transmit the message should be changed to a specified application layer protocol. Action 412 indicates that the message should be encrypted using a particular key. Action 414 indicates that the message should be forwarded towards the message's destination.
In other embodiments, any one of actions 402-414 may be performed individually or in combination with any others of actions 402-414.
3.4 AONS Examples
3.4.1 AONS General Overview
Application-Oriented Network Systems (AONS) is a technology foundation for building a class of products that embed intelligence into the network to better meet the needs of application deployment. AONS complements existing networking technologies by providing a greater degree of awareness of what information is flowing within the network and helping customers to integrate disparate applications by routing information to the appropriate destination, in the format expected by that destination; enforce policies for information access and exchange; optimize the flow of application traffic, both in terms of network bandwidth and processing overheads; provide increased manageability of information flow, including monitoring and metering of information flow for both business and infrastructure purposes; and provide enhanced business continuity by transparently backing up or re-routing critical business data.
AONS provides this enhanced support by understanding more about the content and context of information flow. As such, AONS works primarily at the message rather than at the packet level. Typically, AONS processing of information terminates a TCP connection to inspect the full message, including the “payload” as well as all headers. AONS also understands and assists with popular application-level protocols such as HTTP, FTP, SMTP and de facto standard middleware protocols.
AONS differs from middleware products running on general-purpose computing systems in that AONS' behavior is more akin to a network appliance, in its simplicity, total cost of ownership and performance. Furthermore, AONS integrates with network-layer support to provide a more holistic approach to information flow and management, mapping required features at the application layer into low-level networking features implemented by routers, switches, firewalls and other networking systems.
Although some elements of AONS-like functionality are provided in existing product lines from Cisco Systems, Inc., such products typically work off a more limited awareness of information, such as IP/port addresses or HTTP headers, to provide load balancing and failover solutions. AONS provides a framework for broader functional support, a broader class of applications and a greater degree of control and management of application data.
3.4.2 AONS Terminology
An “application” is a software entity that performs a business function either running on servers or desktop systems. The application could be a packaged application, software running on application servers, a legacy application running on a mainframe, or custom or proprietary software developed in house to satisfy a business need or a script that performs some operation. These applications can communicate with other applications in the same department (departmental), across departments within a single enterprise (intra enterprise), across an enterprise and its partners (inter-enterprise or B2B) or an enterprise and its customers (consumers or B2C). AONS provides value added services for any of the above scenarios.
An “application message” is a message that is generated by an application to communicate with another application. The application message could specify the different business level steps that should be performed in handling this message and could be in any of the message formats described in the section below. In the rest of the document, unless otherwise specified explicitly, the term “message” also refers to an application message.
An “AONS node” is the primary AONS component within the AONS system (or network). As described later, the AONS node can take the shape of a client proxy, server proxy or an intermediate device that routes application messages.
Each application message, when received by the first AONS node, gets assigned an AONS message ID and is considered to be an “AONS message” until that message gets delivered to the destination AONS node. The concept of the AONS message exists within the AONS cloud. A single application message may map to more than one AONS message. This may be the case, for example, if the application message requires processing by more than one business function. For example, a “LoanRequest” message that is submitted by a requesting application and that needs to be processed by both a “CreditCheck” application and a “LoanProcessing” application would require processing by more than one business function. In this example, from the perspective of AONS, there are two AONS messages: The “LoanRequest” to the “CreditCheck” AONS message from the requesting application to the CreditCheck application; and the “LoanRequest” to the “LoanProcessing” AONS message from the CreditCheck application to the LoanProcessing Application.
In one embodiment, AONS messages are encapsulated in an AONP (AON Protocol) header and are translated to a “canonical” format. Reliability, logging and security services are provided from an AONS message perspective.
The set of protocols or methods that applications typically use to communicate with each other are called “application access protocols” (or methods) from an AONS perspective. Applications can communicate to the AONS network (typically end point proxies: a client proxy and a server proxy) using any supported application access methods. Some examples of application access protocols include: IBM MQ Series, Java Message Service (JMS), TIBCO, Simple Object Access Protocol (SOAP) over Hypertext Transfer Protocol (HTTP)/HTTPS, and Simple Mail Transfer Protocol (SMTP). Details about various access methods are explained in later sections of this document.
There are a wide variety of “message formats” that are used by applications. These message formats may range from custom or proprietary formats to industry-specific formats to standardized formats. Extensible Markup Language (XML) is gaining popularity as a universal language or message format for applications to communicate with each other. AONS supports a wide variety of these formats.
In addition, AONS provides translation services from one format to another based on the needs of applications. A typical deployment might involve a first AONS node that receives an application message (the client proxy) translating the message to a “canonical” format, which is carried as an AONS message through the AONS network. The server proxy might translate the message from the “canonical” format to the format understood by the receiving application before delivering the message. For understanding some of the non-industry standard formats, a message dictionary may be used.
A node that performs the gateway functionality between multiple application access methods or protocols is called a “protocol gateway.” An example of this would be a node that receives an application message through File Transfer Protocol (FTP) and sends the same message to another application as a HTTP post. In AONS, the client and server proxies are typically expected to perform the protocol gateway functionality.
If an application generates a message in Electronic Data Interchange (EDI) format and if the receiving application expects the message to be in an XML format, then the message format needs to be translated but the content of the message needs to be kept intact through the translation. In AONS, the end point proxies typically perform this “message format translation” functionality.
In some cases, even though the sending and receiving application use the same message format, the content needs to be translated for the receiving application. For example, if a United States-resident application is communicating with a United Kingdom-resident application, then the date format in the messages between the two applications might need to be translated (from mm/dd/yyyy to dd/mm/yyyy) even if the applications use the same data representation (or message format). This translation is called “content translation.”
3.4.3 AONS Functional Overview
As defined previously, AONS can be defined as network based intelligent intermediary systems that efficiently and efficiently integrate business and application needs with more flexible and responsive network services.
In particular, AONS can be understood through the following characteristics:
AONS operates at a higher layer (layers 5-6) than traditional network element products (layers 2-4). AONS uses message-level inspection as a complement to packet-level inspection—by understanding application messages, AONS adds value to multiple network element products, such as switches, firewalls, content caching systems and load balancers, on the “message exchange route.” AONS provides increased flexibility and granularity of network responsiveness in terms of security, reliability, traffic optimization (compression, caching), visibility (business events and network events) and transformation (e.g., from XML to EDI).
AONS is a comprehensive technology platform, not just a point solution. AONS can be implemented through distributed intelligent intermediary systems that sit between applications, middleware, and databases in a distributed intra- and inter-enterprise environment (routing messages, performing transformations, etc.). AONS provides a flexible framework for end user configuration of business flows and policies and partner-driven extensibility of AONS services.
AONS is especially well suited for network-based deployment. AONS is network-based rather than general-purpose server-based. AONS is hybrid software-based and hardware-based (i.e., application-specific integrated circuit (ASIC)/field programmable gate array (FPGA)-based acceleration). AONS uses out-of-band or in-line processing of traffic, as determined by policy. AONS is deployed in standalone products (network appliances) as well as embedded products (service blades for multiple switching, routing, and storage platforms).
3.4.4 AONS System Overview
This section outlines the system overview of an example AONS system. FIG. 7 is a diagram 700 that illustrates the various components involved in an example AONS network 702 according to one embodiment of the invention. The roles performed by each of the nodes are mentioned in detail in subsequent sections.
Within AONS network 702, key building blocks include AONS Endpoint Proxies (AEPs) 704-710 and an AONS Router (AR). Visibility into application intent may begin within AEP 704 placed at the edge of a logical AONS “cloud.” As a particular client application of client applications 714A-N attempts to send a message across the network to a particular server application destination of server applications 716A-N and 718A-N, the particular client application will first interact with AEP 704.
AEP 704 serves as either a transparent or explicit messaging gateway which aggregates network packets into application messages and infers the message-level intent by examining the header and payload of a given message, relating the message to the appropriate context, optionally applying appropriate policies (e.g. message encryption, transformation, etc.) and then routing the message towards the message's application destination via a network switch.
AONS Router (AR) 712 may intercept the message en route to the message's destination endpoint. Based upon message header contents, AR 712 may determine that a new route would better serve the needs of a given application system. AR 712 may make this determination based upon enterprise-level policy, taking into account current network conditions. As the message nears its destination, the message may encounter AEP 706, which may perform a final set of operations (e.g. message decryption, acknowledgement of delivery) prior to the message's arrival. In one embodiment, each message is only parsed once: when the message first enters the AONS cloud. It is the first AEP that a message traverses that is responsible for preparing a message for optimal handling within the underlying network.
AEPs 704-708 can further be classified into AEP Client Proxies and AEP Server Proxies to explicitly highlight roles and operations performed by the AEP on behalf of the specific end point applications.
A typical message flow involves a particular client application 714A submitting a message to the AEP Client Proxy (CP) 704 through one of the various access protocols supported by AONS. On receiving this message, AEP CP 704 assigns an AONS message id to the message, encapsulates the message with an AONP header, and performs any necessary operations related to the AONS network (e.g. security and reliability services). Also, if necessary, the message is converted to a “canonical” format by AEP CP 704. The message is carried over a TCP connection to AR 710 along the path to the destination application 718A. The AONS routers along the path perform the infrastructure services necessary for the message and can change the routing based on the policies configured by the customer. The message is received at the destination AEP Server Proxy (SP) 706. AEP SP 706 performs necessary security and reliability functions and translates the message to the format that is understood by the receiving application, if necessary. AEP SP 706 then sends the message to receiving application 718A using any of the access protocols that application 718A and AONS support. A detailed message flow through AONS network 702 is described in later sections.
3.4.5 AONS System Elements
This section outlines the different concepts that are used from an AONS perspective.
An “AEP Client Proxy” is an AONS node that performs the services necessary for applications on the sending side of a message (a client). In the rest of this document, an endpoint proxy also refers to a client or server proxy. The typical responsibilities of the client proxy in processing a message are: message pre-classification & early rejection, protocol management, message identity management, message encapsulation in an AONP header, end point origination for reliable delivery, security end point service origination (encryption, digital signature, authentication), flow selection & execution/infrastructure services (logging, compression, content transformation, etc.), routing—next hop AONS node or destination, AONS node and route discovery/advertising role and routes, and end point origination for the reliable delivery mechanism (guaranteed delivery router).
Not all functionalities described above need to be performed for each message. The functionalities performed on the message are controlled by the policies configured for the AONS node.
An “AEP Server Proxy” is an AONS node that performs the services necessary for applications on the receiving side of a message (a server). In the rest of the document, a Server Proxy may also be referred as an end point proxy. The typical responsibilities of the Server Proxy in processing a message are: protocol management, end point termination for reliable delivery, security end point service termination (decryption, verification of digital signature, etc.), flow selection & execution/infrastructure services (logging, compression, content translation, etc.), message de-encapsulation in AONP header, acknowledgement to sending AONS node, application routing/request message delivery to destination, response message correlation, and routing to entry AONS node.
Note that not all the functionalities listed above need to be performed for each message. The functionalities performed on the message are controlled by the policies configured for the AONS node and what the message header indicates.
An “AONS Router” is an AONS node that provides message-forwarding functionalities along with additional infrastructure services within an AONS network. An AONS Router communicates with Client Proxies, Server Proxies and other AONS Routers. An AONS Router may provide service without parsing a message; an AONS Router may rely on an AONP message header and the policies configured in the AONS network instead of parsing messages. An AONS Router provides the following functionalities: scalability in the AONS network in terms of the number of TCP connections needed; message routing based on message destination, policies configured in the AONS cloud, a route specified in the message, and/or content of the message; a load at the intended destination-re-routing if needed; availability of the destination—re-routing if needed; cost of transmission (selection among multiple service providers); and infrastructure services such as sending to a logging facility, sending to a storage area network (SAN) for backup purposes, and interfacing to a cache engine for cacheable messages (like catalogs).
AONS Routers do not need to understand any of the application access protocols and, in one embodiment, deal only with messages encapsulated with an AONP header.
Application-Oriented Networking Protocol (AONP) is a protocol used for communication between the nodes in an AONS network. In one embodiment, each AONS message carries an AONP header that conveys the destination of the message and additional information for processing the message in subsequent nodes. AONP also addresses policy exchange (static or dynamic), fail-over among nodes, load balancing among AONS nodes, and exchange of routing information. AONP also enables application-oriented message processing in multiple network elements (like firewalls, cache engines and routers/switches). AONP supports both a fixed header and a variable header (formed using type-length-value (TLV) fields) to support efficient processing in intermediate nodes as well as flexibility for additional services.
Unless explicitly specified otherwise, “router” or “switch” refers herein to a typical Layer 3 or Layer 2 switch or a router that is currently commercially available.
3.4.6 AONS Example Features
In one embodiment, an underlying “AONS foundation platform of subsystem services” (AOS) provides a range of general-purpose services including support for security, compression, caching, reliability, policy management and other services. On top of this platform, AONS then offers a range of discreet functional components that can be wired together to provide the overall processing of incoming data traffic. These “bladeletsTM” are targeted at effecting individual services in the context of the specific policy or action demanded by the application or the information technology (IT) manager. A series of access method adaptors ensure support for a range of ingress and egress formats. Finally, a set of user-oriented tools enable managers to appropriately view, configure and set policies for the AONS solution. These four categories of functions combine to provide a range of end-customer capabilities including enhanced security, infrastructure optimization, business continuity, application integration and operational visibility.
The enhanced visibility and enhanced responsiveness enabled by AONS solutions provides a number of intelligent, application-oriented network services. These intelligent services can be summarized in four primary categories:
Enhanced security and reliability: enabling reliable message delivery and providing message-level security in addition to existing network-level security.
Infrastructure optimization: making more efficient use of network resources by taking advantage of caching and compression at the message level as well as by integrating application and network quality-of-service (QoS).
Business and infrastructure activity monitoring and management: by reading information contained in the application layer message, AONS can log, audit, and manage application-level business events, and combine these with network, server, and storage infrastructure events in a common, policy-driven management environment.
Content-based routing and transformation: message-based routing and transformation of protocol, content, data, and message formats (e.g., XML transformation). The individual features belonging to each of these primary categories are described in greater detail below.
3.4.6.1 Enhanced Security and Reliability
Authentication: AONS can verify the identity of the sender of an inbound message based upon various pieces of information contained within a given message (username/password, digital certificate, Security Assertion Markup Language (SAML) assertion, etc.), and, based upon these credentials, determine whether or not the message should be processed further.
Authorization: Once principal credentials are obtained via message inspection, AONS can determine what level of access the originator of the message should have to the services it is attempting to invoke. AONS may also make routing decisions based upon such derived privileges or block or mask certain data elements within a message once it's within an AONS network as appropriate.
Encryption/Decryption: Based upon policy, AONS can perform encryption of message elements (an entire message, the message body or individual elements such as credit card number) to maintain end-to-end confidentiality as a message travels through the AONS network. Conversely, AONS can perform decryption of these elements prior to arrival at a given endpoint.
Digital Signatures: In order to ensure message integrity and allow for non-repudiation of message transactions, AONS can digitally sign entire messages or individual message elements at any given AEP. The decision as to what gets signed will be determined by policy as applied to information derived from the contents and context of each message.
Reliability: AONS can complement existing guaranteed messaging systems by intermediating between unlike proprietary mechanisms. It can also provide reliability for HTTP-based applications (including web services) that currently lack reliable delivery. As an additional feature, AONS can generate confirmations of successful message delivery as well as automatically generate exception responses when delivery cannot be confirmed.
3.4.6.2 Infrastructure Optimization
Compression: AEPs can compress message data prior to sending the message data across the network in order to conserve bandwidth and conversely decompress it prior to endpoint delivery.
Caching: AONS can cache the results of previous message inquires based upon the rules defined for a type of request or based upon indicators set in the response. Caching can be performed for entire messages or for certain elements of a message in order to reduce application response time and conserve network bandwidth utilization. Message element caching enables delta processing for subsequent message requests.
TCP Connection Pooling: By serving as an intermediary between message clients and servers AONS can consolidate the total number of persistent connections required between applications. AONS thereby reduces the client and server-processing load otherwise associated with the ongoing initiation and teardown of connections between a mesh of endpoints.
Batching: An AONS intermediary can batch transactional messages destined for multiple destinations to reduce disk I/O overheads on the sending system. Similarly, transactional messages from multiple sources can be batched to reduce disk I/O overheads on the receiving system.
Hardware Acceleration: By efficiently performing compute-intensive functions such as encryption and Extensible Stylesheet Language Transformation (XSLT) transformations in an AONS network device using specialized hardware, AONS can offload the computing resources of endpoint servers, providing potentially lower-cost processing capability.
Quality of Service: AONS can integrate application-level QoS with network-level QoS features based on either explicit message prioritization (e.g., a message tagged as “high priority”) or via policy that determines when a higher quality of network service is required for a message as specific message content is detected.
Policy Enforcement: At the heart of optimizing the overall AONS solution is the ability to ensure business-level polices are expressed, implemented and enforced by the infrastructure. The AONS Policy Manager ensures that once messages are inspected, the appropriate actions (encryption, compression, routing, etc.) are taken against that message as appropriate.
3.4.6.3 Activity Monitoring and Management
Auditing/Logging/Metering: AONS can selectively filter messages and send them to a node or console for aggregation and subsequent analysis. Tools enable viewing and analysis of message traffic. AONS can also generate automatic responses to significant real-time events, both business and infrastructure-related. By intelligently gathering statistics and sending them to be logged, AONS can produce metering data for auditing or billing purposes.
Management: AONS can combine both message-level and network infrastructure level events to gain a deeper understanding of overall system health. The AONS management interface itself is available as a web service for those who wish to access it programmatically.
Testing and Validation: AONS' ability to intercept message traffic can be used to validate messages before allowing them to reach destination applications. In addition to protecting from possible application or server failures, this capability can be leveraged to test new web services and other functions by examining actual message flow from clients and servers prior to production deployment. AONS also provides a “debug mode” that can be turned on automatically after a suspected failure or manually after a notification to assist with the overall management of the device.
Workload Balancing and Failover: AONS provides an approach to workload balancing and failover that is both policy- and content-driven. For example, given an AONS node's capability to intermediate between heterogeneous systems, the AONS node can balance between unlike systems that provide access to common information as requested by the contents of a message. AONS can also address the issue of message affinity necessary to ensure failover at the message rather than just the session level as is done by most existing solutions. Balancing can also take into account the response time for getting a message reply, routing to an alternate destination if the preferred target is temporarily slow to respond.
Business Continuity: By providing the ability to replicate inbound messages to a remote destination, AONS enables customers to quickly recover from system outages. AONS can also detect failed message delivery and automatically re-route to alternate endpoints. AONS AEPs and ARs themselves have built-in redundancy and failover at the component level and can be clustered to ensure high availability.
3.4.6.4 Content-Based Routing and Transformation
Content-based Routing: Based upon its ability to inspect and understand the content and context of a message, AONS provides the capability to route messages to an appropriate destination by matching content elements against pre-established policy configurations. This capability allows AONS to provide a common interface (service virtualization) for messages handled by different applications, with AONS examining message type or fields in the content (part number, account type, employee location, customer zip code, etc.) to route the message to the appropriate application. This capability also allows AONS to send a message to multiple destinations (based on either statically defined or dynamic subscriptions to message types or information topics), with optimal fan-out through AONS routers. This capability further allows AONS to redirect all messages previously sent to an application so that it can be processed by a new application. This capability additionally allows AONS to route a message for a pre-processing step that is deemed to be required before receipt of a message (for example, introducing a management pre-approval step for all travel requests). Thus capability also allows AONS to route a copy of a message that exceeds certain criteria (e.g. value of order) to an auditing system, as well as forwarding the message to the intended destination. This capability further allows AONS to route a message to a particular server for workload or failover reasons. This capability also allows AONS to route a message to a particular server based on previous routing decisions (e.g., routing a query request based on which server handled for the original order). This capability additionally allows AONS to route based on the source of a message. This capability also allows AONS to route a message through a sequence of steps defined by a source or previous intermediary.
Message Protocol Gateway: AONS can act as a gateway between applications using different transport protocols. AONS supports open standard protocols (e.g. HTTP, FTP, SMTP), as well as popular or de facto standard proprietary protocols such as IBM Websphere MQ.
Message Transformations: AONS can transform the contents of a message to make them appropriate for a particular receiving application. This can be done for both XML and non-XML messages, the latter via the assistance of either a message dictionary definition or a well-defined industry standard format.
3.4.7 AONS Functional Modules
FIG. 8 is a block diagram that depicts functional modules within an example AONS node. AONS node 800 comprises AOS configuration and management module 802, flows/rules 804, AOS common services 806, AOS message execution controller 808, AOS protocol access methods 810, and AOS platform-specific “glue” 812. AONS node 800 interfaces with Internetworking Operating System (IOS) 814 and Linux Operating System 816. Flows/rules 804 comprise bladeletsTM 818, scriptletsTM 820, and scriptletTM container 822.
In one embodiment, AOS common services 806 include: security services, standard compression services, delta compression services, caching service, message logging service, policy management service, reliable messaging service, publish/subscribe service, activity monitoring service, message distribution service, XML parsing service, XSLT transformation service, and QoS management service.
In one embodiment, AOS protocol/access methods 810 include: TCP/SSL, HTTP/HTTPS, SOAP/HTTP, SMTP, FTP, JMS/MQ and JMS/RV, and Java Database Connectivity (JDBC).
In one embodiment, AOS message execution controller 808 includes: an execution controller, a flow subsystem, and a bladeletTM subsystem.
In one embodiment, AOS bladeletsTM 818 and scriptletsTM 820 include: message input (read message), message output (send message), logging/audit, decision, external data access, XML parsing, XML transformation, caching, scriptlet container, publish, subscribe, message validation (schema, format, etc.), filtering/masking, signing, authentication, authorization, encryption, decryption, activity monitoring sourcing, activity monitoring marking, activity monitoring processing, activity monitoring notification, message discard, firewall block, firewall unblock, message intercept, and message stop-intercept.
In one embodiment, AOS configuration and management module 802 includes: configuration, monitoring, topology management, capability exchange, failover redundancy, reliability/availability/serviceability (RAS) services (tracing, debugging, etc.), archiving, installation, upgrades, licensing, sample scriptletsTM, sample flows, documentation, online help, and language localization.
In one embodiment, supported platforms include: Cisco Catalyst 6503, Cisco Catalyst 6505, Cisco Catalyst 6509, and Cisco Catalyst 6513. In one embodiment, supported supervisor modules include: Sup2 and Sup720. In one embodiment, specific functional areas relating to the platform include: optimized TCP, SSL, public key infrastructure (PKI), encryption/decryption, interface to Cat6K supervisor, failover/redundancy, image management, and QoS functionality.
3.4.8 AONS Modes of Operation
AONS may be configured to run in multiple modes depending on application integration needs, and deployment scenarios. According to one embodiment, the primary modes of operation include implicit mode, explicit mode, and proxy mode. In implicit mode, an AONS node transparently intercepts relevant traffic with no changes to applications. In explicit mode, applications explicitly address traffic to an intermediary AONS node. In proxy mode, applications are configured to work in conjunction with AONS nodes, but applications do not explicitly address traffic to AONS nodes.
In implicit mode, applications are unaware of AONS presence. Messages are address to receiving applications. Messages are redirected to AONS via configuration of application “proxy” or middleware systems to route messages to AONS, and/or via configuration of networks (packet interception). For example, domain name server (DNS)-based redirection could be used to route messages. For another example, a 5-tuple-based access control list (ACL) on a switch or router could be used. Network-based application recognition and content switching modules may be configured for URL/URI redirection. Message-based inspection may be used to determine message types and classifications. In implicit mode, applications communicate with each other using AONS as an intermediary (implicitly), using application-native protocols.
Traffic redirection, message classification, and “early rejection” (sending traffic out of AONS layers prior to complete processing within AONS layers) may be accomplished via a variety of mechanisms, such as those depicted in FIG. 9. FIG. 9 shows multiple tiers of filtering that may be performed on message traffic in order to produce only a select set of traffic that will be processed at the AONS layer. Traffic that is not processed at the AONS layer may be treated as any other traffic.
At the lowest layer, layer 902, all traffic passes through. At the next highest layer, layer 904, traffic may be filtered based on 5-tuples. A supervisor blade or Internetwork Operating System (IOS) may perform such filtering. Traffic that passes the filters at layer 904 passes to layer 906. At layer 906, traffic may be further filtered based on network-based application recognition-like filtering and/or message classification and rejection. Traffic that passes the filters at layer 906 passes to layer 908. At layer 908, traffic may be further filtered based on protocol headers. For example, traffic may be filtered based on URLs/URIs in the traffic. Traffic that passes the filters at layer 908 passes to layer 910. At layer 910, traffic may be processed based on application layer messages, include headers and contents. For example, XPath paths within messages may be used to process traffic at layer 910. An AONS blade may perform processing at layer 910. Thus, a select subset of all network traffic may be provided to an AONS blade.
In explicit mode, applications are aware of AONS presence. Messages are explicitly addressed to AONS nodes. Applications may communicate with AONS using AONP. AONS may perform service virtualization and destination selection.
In proxy mode, applications are explicitly unaware of AONS presence. Messages are addressed to their ultimate destinations (i.e., applications). However, client applications are configured to direct traffic via a proxy mode.
3.4.9 AONS Message Routing
Components of message management in AONS may be viewed from two perspectives: a node view and a cloud view.
FIG. 10 is a diagram that illustrates the path of a message within an AONS cloud 1010 according to a cloud view. A client application 1004 sends a message to an AONS Client Proxy (CP) 1006. If AONS CP 1006 is not present, then client application 1004 may send the message to an AONS Server Proxy (SP) 1008. The message is processed at AONS CP 1006. AONS CP 1006 transforms the message into AONP format if the message is entering AONS cloud 1010.
Within AONS cloud 1010, the message is routed using AONP. Thus, using AONP, the message may be routed from AONS CP 1006 to an AONS router 1012, or from AONS CP 1006 to AONS SP 1008, or from AONS router 1012 to another AONS router, or from AONS router 1012 to AONS SP 1008. Messages processed at AONS nodes are processed in AONP format.
When the message reaches AONS SP 1008, AONS SP 1008 transforms the message into the message format used by server application 1014. AONS SP 1008 routes the message to server application 1014 using the message protocol of server application 1014. Alternatively, if AONS SP 1008 is not present, AONS CP 1006 may route the message to server application 1014.
The details of the message processing within AONS cloud 1010 can be understood via the following perspectives: Request/Response Message Flow, One-Way Message Flow, Message Flow with Reliable Delivery, and Node-to-Node Communication.
FIG. 11A and FIG. 11B are diagrams that illustrate a request/response message flow. Referring to FIG. 11A, at circumscribed numeral 1, a sending application 1102 sends a message towards a receiving application 1104. At circumscribed numeral 2, an AEP CP 1106 intercepts the message and adds an AONP header to the message, forming an AONP message. At circumscribed numeral 3, AEP CP 1106 sends the AONP message to an AONS router 1108. At circumscribed numeral 4, AONS router 1108 receives the AONP message. At circumscribed numeral 5, AONS router 1108 sends the AONP message to an AEP SP 1110. At circumscribed numeral 6, AEP SP 1110 receives the AONP message and removes the AONP header from the message, thus decapsulating the message. At circumscribed numeral 7, AEP SP 1110 sends the message to receiving application 1104.
Referring to FIG. 11B, at circumscribed numeral 8, receiving application 1104 sends a response message toward sending application 1102. At circumscribed numeral 9, AEP SP 1110 intercepts the message and adds an AONP header to the message, forming an AONP message. At circumscribed numeral 10, AEP SP 1110 sends the AONP message to AONS router 1108. At circumscribed numeral 11, AONS router 1108 receives the AONP message. At circumscribed numeral 12, AONS router 1108 sends the AONP message to AEP CP 1106. At circumscribed numeral 13, AEP CP 1106 receives the AONP message and removes the AONP header from the message, thus decapsulating the message. At circumscribed numeral 14, AEP CP 1106 sends the message to sending application 1102. Thus, a request is routed from sending application 1102 to receiving application 1104, and a response is routed from receiving application 1104 to sending application 1102.
FIG. 12A and FIG. 12B are diagrams that illustrate alternative request/response message flows. FIG. 12A shows three possible routes that a message might take from a sending application 1202 to a receiving application 1204. According to a first route, sending application 1202 sends the message toward receiving application 1204, but an AEP CP 1206 intercepts the message and sends the message to receiving application 1204. According to a second route, sending application 1202 sends the message toward receiving application 1204, but AEP CP 1206 intercepts the message, encapsulates the message within an AONP message, and sends the AONP message to an AEP SP 1208, which decapsulates the message from the AONP message and sends the message to receiving application 1204. According to a third route, sending application 1202 sends the message toward receiving application 1204, but AEP SP 1208 intercepts the message and sends the message to receiving application 1204.
FIG. 12B shows three possible routes that a response message might take from receiving application 1204 to sending application 1202. According to a first route, receiving application 1204 sends the message toward sending application 1202, but AEP CP 1206 intercepts the message and sends the message to sending application 1204. According to a second route, receiving application 1204 sends the message toward sending application 1202, but AEP SP 1208 intercepts the message, encapsulates the message within an AONP message, and sends the AONP message to AEP CP 1206, which decapsulates the message from the AONP message and sends the message to sending application 1202. According to a third route, receiving application 1204 sends the message toward sending application 1202, but AEP SP 1208 intercepts the message and sends the message to sending application 1202.
FIG. 13 is a diagram that illustrates a one-way message flow. At circumscribed numeral 1, a sending application 1302 sends a message towards a receiving application 1304. At circumscribed numeral 2, an AEP CP 1306 intercepts the message and adds an AONP header to the message, forming an AONP message. At circumscribed numeral 3, AEP CP 1306 sends an ACK (acknowledgement) back to sending application 1302. At circumscribed numeral 4, AEP CP 1306 sends the AONP message to an AONS router 1308. At circumscribed numeral 5, AONS router 1308 receives the AONP message. At circumscribed numeral 6, AONS router 1308 sends the AONP message to an AEP SP 1310. At circumscribed numeral 7, AEP SP 1310 receives the AONP message and removes the AONP header from the message, thus decapsulating the message. At circumscribed numeral 8, AEP SP 1310 sends the message to receiving application 1304.
FIG. 14 is a diagram that illustrates alternative one-way message flows. FIG. 14 shows three possible routes that a message might take from a sending application 1402 to a receiving application 1404. According to a first route, sending application 1402 sends the message toward receiving application 1404, but an AEP CP 1406 intercepts the message and sends the message to receiving application 1404. AEP CP 1406 sends an ACK (acknowledgement) to sending application 1402. According to a second route, sending application 1402 sends the message toward receiving application 1404, but AEP CP 1406 intercepts the message, encapsulates the message within an AONP message, and sends the AONP message to an AEP SP 1408, which decapsulates the message from the AONP message and sends the message to receiving application 1404. Again, AEP CP 1406 sends an ACK to sending application 1402. According to a third route, sending application 1402 sends the message toward receiving application 1404, but AEP SP 1408 intercepts the message and sends the message to receiving application 1404. In this case, AEP SP 1408 sends an ACK to sending application 1402. Thus, when an AEP intercepts a message, the intercepting AEP sends an ACK to the sending application.
According to one embodiment, AONP is used in node-to-node communication with the next hop. In one embodiment, AONP uses HTTP. AONP headers may include HTTP or TCP headers. AONP may indicate RM ACK, QoS level, message priority, and message context (connection, message sequence numbers, message context identifier, entry node information, etc.). The actual message payload is in the message body. Asynchronous messaging may be used between AONS nodes. AONS may conduct route and node discovery via static configuration (next hop) and/or via dynamic discovery and route advertising (“lazy” discovery).
FIG. 15A and FIG. 15B are diagrams that illustrate a request/response message flow with reliable message delivery. Referring to FIG. 15A, at circumscribed numeral 1, a sending application 1502 sends a message towards a receiving application 1504. At circumscribed numeral 2, an AEP CP 1506 intercepts the message and adds an AONP header to the message, forming an AONP message. At circumscribed numeral 3, AEP CP 1506 saves the message to a data store 1512. Thus, if there are any problems with sending the message, AEP CP 1506 can resend the copy of the message that is stored in data store 1512.
At circumscribed numeral 4, AEP CP 1506 sends the AONP message to an AONS router 1508. At circumscribed numeral 5, AONS router 1508 receives the AONP message. At circumscribed numeral 6, AONS router 1508 sends the AONP message to an AEP SP 1510. At circumscribed numeral 7, AEP SP 1510 receives the AONP message and removes the AONP header from the message, thus decapsulating the message. At circumscribed numeral 8, AEP SP 1510 sends the message to receiving application 1504.
At circumscribed numeral 9, AEP SP 1510 sends a reliable messaging (RM) acknowledgement (ACK) to AONS router 1508. At circumscribed numeral 10, AONS router 1508 receives the RM ACK and sends the RM ACK to AEP CP 1506. At circumscribed numeral 11, AEP CP 1506 receives the RM ACK and, in response, deletes the copy of the message that is stored in data store 1512. Because the delivery of the message has been acknowledged, there is no further need to store a copy of the message in data store 1512. Alternatively, if AEP CP 1506 does not receive the RM ACK within a specified period of time, then AEP CP 1506 resends the message.
Referring to FIG. 15B, at circumscribed numeral 12, receiving application 1504 sends a response message toward sending application 1502. At circumscribed numeral 13, AEP SP 1510 intercepts the message and adds an AONP header to the message, forming an AONP message. At circumscribed numeral 14, AEP SP 1510 sends the AONP message to AONS router 1508. At circumscribed numeral 15, AONS router 1508 receives the AONP message. At circumscribed numeral 16, AONS router 1508 sends the AONP message to AEP CP 1506. At circumscribed numeral 17, AEP CP 1506 receives the AONP message and removes the AONP header from the message, thus decapsulating the message. At circumscribed numeral 18, AEP CP 1506 sends the message to sending application 1502.
FIG. 16 is a diagram that illustrates a one-way message flow with reliable message delivery. At circumscribed numeral 1, a sending application 1602 sends a message towards a receiving application 1604. At circumscribed numeral 2, an AEP CP 1606 intercepts the message and adds an AONP header to the message, forming an AONP message. At circumscribed numeral 3, AEP CP 1606 saves the message to a data store 1612. Thus, if there are any problems with sending the message, AEP CP 1606 can resend the copy of the message that is stored in data store 1612. At circumscribed numeral 4, AEP CP 1606 sends an ACK (acknowledgement) back to sending application 1602. At circumscribed numeral 5, AEP CP 1606 sends the AONP message to an AONS router 1608. At circumscribed numeral 6, AONS router 1608 receives the AONP message. At circumscribed numeral 7, AONS router 1608 sends the AONP message to an AEP SP 1610. At circumscribed numeral 8, AEP SP 1610 receives the AONP message and removes the AONP header from the message, thus decapsulating the message. At circumscribed numeral 9, AEP SP 1610 sends the message to receiving application 1604.
At circumscribed numeral 10, AEP SP 1610 sends a reliable messaging (RM) acknowledgement (ACK) to AONS router 1608. At circumscribed numeral 11, AONS router 1608 receives the RM ACK and sends the RM ACK to AEP CP 1606. At circumscribed numeral 12, AEP CP 1606 receives the RM ACK and, in response, deletes the copy of the message that is stored in data store 1612. Because the delivery of the message has been acknowledged, there is no further need to store a copy of the message in data store 1612. Alternatively, if AEP CP 1606 does not receive the RM ACK within a specified period of time, then AEP CP 1606 resends the message.
FIG. 17 is a diagram that illustrates synchronous request and response messages. At circumscribed numeral 1, an AONS node 1704 receives, from a client 1702, a request message, in either implicit or explicit mode. At circumscribed numeral 2, AONS node 1704 reads the message, selects and executes a flow, and adds an AONP header to the message. At circumscribed numeral 3, AONS node 1704 sends the message to a next hop node, AONS node 1706. At circumscribed numeral 4, AONS node 1706 reads the message, selects and executes a flow, and removes the AONP header from the message, formatting the message according to the message format expected by a server 1708. At circumscribed numeral 5, AONS node 1706 sends the message to the message's destination, server 1708.
At circumscribed numeral 6, AONS node 1706 receives a response message from server 1708 on the same connection on which AONS node 1706 sent the request message. At circumscribed numeral 7, AONS node 1706 reads the message, correlates the message with the request message, executes a flow, and adds an AONP header to the message. At circumscribed numeral 8, AONS node 1706 sends the message to AONS node 1704. At circumscribed numeral 9, AONS node 1704 reads the message, correlates the message with the request message, executes a flow, and removes the AONP header from the message, formatting the message according to the message format expected by client 1702. At circumscribed numeral 10, AONS node 1704 sends the message to client 1702 on the same connection on which client 1702 sent the request message to AONS node 1704.
FIG. 18 is a diagram that illustrates a sample one-way end-to-end message flow. At circumscribed numeral 1, an AONS node 1804 receives, from a client 1802, a request message, in either implicit or explicit mode. At circumscribed numeral 2, AONS node 1804 reads the message, selects and executes a flow, and adds an AONP header to the message. At circumscribed numeral 3, AONS node 1804 sends an acknowledgement to client 1802. At circumscribed numeral 4, AONS node 1804 sends the message to a next hop node, AONS node 1806. At circumscribed numeral 5, AONS node 1806 reads the message, selects and executes a flow, and removes the AONP header from the message, formatting the message according to the message format expected by a server 1808. At circumscribed numeral 6, AONS node 1806 sends the message to the message's destination, server 1808.
According to the node view, the message lifecycle within an AONS node, involves ingress/egress processing, message processing, message execution control, and flow execution.
FIG. 19 is a diagram that illustrates message-processing modules within an AONS node 1900. AONS node 1900 comprises an AONS message execution controller (AMEC) framework 1902, a policy management subsystem 1904, an AONS message processing infrastructure subsystem 1906, and an AOSS 1908. AMEC framework 1902 comprises a flow management subsystem 1910, a bladeletTM execution subsystem 1912, and a message execution controller 1914. Policy management subsystem 1904 communicates with flow management subsystem 1910. AOSS 1908 communicates with bladeletTM execution subsystem 1912 and AONS message processing infrastructure subsystem 1906. AONS message processing infrastructure subsystem 1906 communicates with message execution controller 1914. Flow management subsystem 1910, bladeletTM execution subsystem, and message execution controller 1914 all communicate with each other.
FIG. 20 is a diagram that illustrates message processing within AONS node 1900. AMEC framework 1902 is an event-based multi-threaded mechanism to maximize throughput while minimizing latency for messages in the AONS node. According to one embodiment, received packets are re-directed, TCP termination is performed, SSL termination is performed if needed, Layer 5 protocol adapter and access method processing is performed (using access methods such as HTTP, SMTP, FTP, JMS/MQ, JMS/RV, JDBC, etc.), AONS messages (normalized message format for internal AONS processing) are formed, messages are queued, messages are dequeued based on processing thread availability, a flow (or rule) is selected, the selected flow is executed, the message is forwarded to the message's destination, and for request/response-based semantics, responses are handled via connection/session state maintained within AMEC framework 1902.
In one embodiment, executing the flow comprises executing each step (i.e., bladeletTM/action) of the flow. If a bladeletTM is to be run within a separate context, then AMEC framework 1902 may enqueue into bladeletTM-specific queues, and, based on thread availability, dequeue appropriate bladeletTM states from each bladeletTM queue.
3.4.10 Flows, BladeletsTM, and ScriptletsTM
According to one embodiment, flows string together bladeletsTM (i.e., actions) to customize message processing logic. ScriptletsTM provide a mechanism for customers and partners to customize or extend native AONS functionality. Some bladeletsTM and services may be provided with an AONS node.
3.4.11 AONS Services
As mentioned in the previous section, a set of core services may be provided by AONS to form the underlying foundation of value-added functionality that can be delivered via an AONS node. In one embodiment, these include: Security Services, Standard Compression Services, Delta Compression Services, Caching Service, Message Logging Service, Policy Management Service (Policy Manager), Reliable Messaging Service, Publish/Subscribe Service, Activity Monitoring Service, Message Distribution Service, XML Parsing Service, XSLT Transformation Service, and QoS Management Service. In one embodiment, each AONS core service is implemented within the context of a service framework.
3.4.12 AONS Configuration and Management
In one embodiment, an AONS node is provisioned and configured for a class of application messages, where it enforces the policies that are declaratively defined on behalf-of the application end-points, business-domains, security-domains, administrative domains, and network-domains. Furthermore, the AONS node promotes flexible composition and customization of different product functional features by means of configurability and extensibility of different software and hardware sub-systems for a given deployment scenario. Due to the application and network embodiments of the AONS functionality, the AONS architecture framework should effectively and uniformly address different aspects of configurability, manageability, and monitorability of the various system components and their environments.
The AONS Configuration and Management framework is based upon five functional areas (“FCAPS”) for network management as recommended by the ISO network management forum. The functional areas include fault management, configuration management, accounting management, performance management, and security management. Fault management is the process of discovering, isolating, and fixing the problems or faults in the AONS nodes. Configuration management is the process of finding and setting up the AONS nodes. Accounting management involves tracking usage and utilization of AONS resources to facilitate their proper usage. Performance management is the process of measuring the performance of the AONS system components and the overall system. Security management controls access to information on the AONS system. Much of the above functionality is handled via proper instrumentation, programming interfaces, and tools as part of the overall AONS solution.
FIG. 21, FIG. 22, and FIG. 23 are diagrams that illustrate entities within an AONS configuration and management framework. A configuring and provisioning server (CPS) is the centralized hub for configuration and management of AONS policies, flows, scriptletsTM and other manageable entities. Configurable data is pushed to the CPS from an AONS design studio (flow tool) and the AONS admin may then provision this data to the production deployment. A promotion process is also provided to test and validate changes via a development to staging/certification to production rollout process. A configuration and provisioning agent (CPA) resides on individual AONS blades and provides the local control and dispatch capabilities for AONS. The CPA interacts with the CPS to get updates. The CPA takes appropriate actions to implement changes. The CPA is also used for collecting monitoring data to report to third party consoles.
3.4.13 AONS Monitoring
In one embodiment, AONS is instrumented to support well-defined events for appropriate monitoring and visibility into internal processing activities. The monitoring of AONS nodes may be accomplished via a pre-defined JMX MBean agent that is running on each AONS node. This agent communicates with a remote JMX MBean server on the PC complex. An AONS MIB is leveraged for SNMP integration to third party consoles. FIG. 24 is a diagram that illustrates an AONS monitoring architecture.
3.4.14 AONS Tools
In one embodiment, the following tool sets are provided for various functional needs of AONS: a design studio, an admin studio, and a message log viewer. The design studio is a visual tool for designing flows and applying message classification and mapping policies. The admin studio is a web-based interface to perform all administration and configuration functions. The message log viewer is a visual interface to analyze message traffic, patterns, and trace information.
4.0 Implementation Mechanisms—Hardware Overview
FIG. 5 is a block diagram that illustrates a computer system 500 upon which an embodiment of the invention may be implemented. The preferred embodiment is implemented using one or more computer programs running on a network element such as a proxy device. Thus, in this embodiment, the computer system 500 is a proxy device such as a load balancer.
Computer system 500 includes a bus 502 or other communication mechanism for communicating information, and a processor 504 coupled with bus 502 for processing information. Computer system 500 also includes a main memory 506, such as a random access memory (RAM), flash memory, or other dynamic storage device, coupled to bus 502 for storing information and instructions to be executed by processor 504. Main memory 506 also may be used for storing temporary variables or other intermediate information during execution of instructions to be executed by processor 504. Computer system 500 further includes a read only memory (ROM) 508 or other static storage device coupled to bus 502 for storing static information and instructions for processor 504. A storage device 510, such as a magnetic disk, flash memory or optical disk, is provided and coupled to bus 502 for storing information and instructions.
A communication interface 518 may be coupled to bus 502 for communicating information and command selections to processor 504. Interface 518 is a conventional serial interface such as an RS-232 or RS-322 interface. An external terminal 512 or other computer system connects to the computer system 500 and provides commands to it using the interface 514. Firmware or software running in the computer system 500 provides a terminal interface or character-based command interface so that external commands can be given to the computer system.
A switching system 516 is coupled to bus 502 and has an input interface 514 and an output interface 519 to one or more external network elements. The external network elements may include a local network 522 coupled to one or more hosts 524, or a global network such as Internet 528 having one or more servers 530. The switching system 516 switches information traffic arriving on input interface 514 to output interface 519 according to pre-determined protocols and conventions that are well known. For example, switching system 516, in cooperation with processor 504, can determine a destination of a packet of data arriving on input interface 514 and send it to the correct destination using output interface 519. The destinations may include host 524, server 530, other end stations, or other routing and switching devices in local network 522 or Internet 528.
The invention is related to the use of computer system 500 for avoiding the storage of client state on computer system 500. According to one embodiment of the invention, computer system 500 provides for such updating in response to processor 504 executing one or more sequences of one or more instructions contained in main memory 506. Such instructions may be read into main memory 506 from another computer-readable medium, such as storage device 510. Execution of the sequences of instructions contained in main memory 506 causes processor 504 to perform the process steps described herein. One or more processors in a multi-processing arrangement may also be employed to execute the sequences of instructions contained in main memory 506. In alternative embodiments, hard-wired circuitry may be used in place of or in combination with software instructions to implement the invention. Thus, embodiments of the invention are not limited to any specific combination of hardware circuitry and software.
The term “computer-readable medium” as used herein refers to any medium that participates in providing instructions to processor 504 for execution. Such a medium may take many forms, including but not limited to, non-volatile media, volatile media, and transmission media. Non-volatile media includes, for example, optical or magnetic disks, such as storage device 510. Volatile media includes dynamic memory, such as main memory 506. Transmission media includes coaxial cables, copper wire and fiber optics, including the wires that comprise bus 502. Transmission media can also take the form of acoustic or light waves, such as those generated during radio wave and infrared data communications.
Common forms of computer-readable media include, for example, a floppy disk, a flexible disk, hard disk, magnetic tape, or any other magnetic medium, a CD-ROM, any other optical medium, punch cards, paper tape, any other physical medium with patterns of holes, a RAM, a PROM, and EPROM, a FLASH-EPROM, any other memory chip or cartridge, a carrier wave as described hereinafter, or any other medium from which a computer can read.
Various forms of computer readable media may be involved in carrying one or more sequences of one or more instructions to processor 504 for execution. For example, the instructions may initially be carried on a magnetic disk of a remote computer. The remote computer can load the instructions into its dynamic memory and send the instructions over a telephone line using a modem. A modem local to computer system 500 can receive the data on the telephone line and use an infrared transmitter to convert the data to an infrared signal. An infrared detector coupled to bus 502 can receive the data carried in the infrared signal and place the data on bus 502. Bus 502 carries the data to main memory 506, from which processor 504 retrieves and executes the instructions. The instructions received by main memory 506 may optionally be stored on storage device 510 either before or after execution by processor 504.
Communication interface 518 also provides a two-way data communication coupling to a network link 520 that is connected to a local network 522. For example, communication interface 518 may be an integrated services digital network (ISDN) card or a modem to provide a data communication connection to a corresponding type of telephone line. As another example, communication interface 518 may be a local area network (LAN) card to provide a data communication connection to a compatible LAN. Wireless links may also be implemented. In any such implementation, communication interface 518 sends and receives electrical, electromagnetic or optical signals that carry digital data streams representing various types of information.
Network link 520 typically provides data communication through one or more networks to other data devices. For example, network link 520 may provide a connection through local network 522 to a host computer 524 or to data equipment operated by an Internet Service Provider (ISP) 526. ISP 526 in turn provides data communication services through the worldwide packet data communication network now commonly referred to as the “Internet” 528. Local network 522 and Internet 528 both use electrical, electromagnetic or optical signals that carry digital data streams. The signals through the various networks and the signals on network link 520 and through communication interface 518, which carry the digital data to and from computer system 500, are exemplary forms of carrier waves transporting the information.
Computer system 500 can send messages and receive data, including program code, through the network(s), network link 520 and communication interface 518. In the Internet example, a server 530 might transmit a requested code for an application program through Internet 528, ISP 526, local network 522 and communication interface 518. In accordance with the invention, one such downloaded application provides for avoiding the storage of client state on a server as described herein.
Processor 504 may execute the received code as it is received and/or stored in storage device 510 or other non-volatile storage for later execution. In this manner, computer system 500 may obtain application code in the form of a carrier wave.
5.0 Extensions and Alternatives
In the foregoing specification, the invention has been described with reference to specific embodiments thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the invention. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.

## Claims

1. A method of providing reliable delivery of an application layer message, the method comprising the computer-implemented steps of:
receiving one or more data packets at a first network element;
determining a first application layer message that is collectively contained in one or more payload portions of the one or more data packets, wherein the first application layer message originated at a source application;
extracting, from the first application layer message, a message identifier that is contained in the first application layer message;
determining whether a message identifier queue contains the message identifier; and
in response to determining that the message identifier queue does not contain the message identifier, storing the first application layer message in an application layer message queue as well as storing the message identifier into the message identifier queue atomically, and sending towards the source application, an acknowledgment (ACK) message that indicates the message identifier;
wherein the method is performed by one or more computing devices of the first network element located between the source application and a destination of the first application layer message.

2. A method as recited in claim 1 wherein the storing comprises storing in a persistent storage device that is coupled to the router and coupled to the destination.

3. A method as recited in claim 1, further comprising:
in response to determining that the message identifier queue contains the message identifier, sending the acknowledgment (ACK) message toward the source application without storing the first application layer message in the application layer message queue.

4. A method as recited in claim 1, wherein the message identifier was added to the first application layer message by a second network element that is separate from both the first network element and a device that hosts the source application.

5. A method as recited in claim 1, wherein receiving the one or more data packets comprises intercepting the one or more data packets at the first network element, and wherein the one or more data packets are destined for a destination application rather than the first network element.

6. A method as recited in claim 1, wherein the first network element is a network switch or router.

7. A non-transitory computer-readable volatile or non-volatile storage medium carrying one or more sequences of instructions for providing reliable delivery of an application layer message, which instructions, when executed by one or more processors, cause the one or more processors to carry out the steps of:
receiving one or more data packets at a first network element;
determining a first application layer message that is collectively contained in one or more payload portions of the one or more data packets, wherein the first application layer message originated at a source application;
extracting, from the first application layer message, a message identifier that is contained in the first application layer message;
determining whether a message identifier queue contains the message identifier; and
in response to determining that the message identifier queue does not contain the message identifier, storing the first application layer message in an application layer message queue as well as storing the message identifier into the message identifier queue atomically, and sending, towards the source application, an acknowledgment (ACK) message that indicates the message identifier;
wherein the first network element is located between the source application and a destination of the first application layer message.

8. A non-transitory computer-readable volatile or non-volatile storage medium as recited in claim 7, wherein instructions which cause the storing comprise instructions which when executed cause storing in a persistent storage device that is coupled to the router and coupled to the destination.

9. A non-transitory computer-readable volatile or non-volatile storage medium as recited in claim 7, wherein the steps further comprise:
in response to determining that the message identifier queue contains the message identifier, sending the acknowledgment (ACK) message toward the source application without storing the first application layer message in the application layer message queue.

10. A non-transitory computer-readable volatile or non-volatile storage medium as recited in claim 7, wherein the message identifier was added to the first application layer message by a second network element that is separate from both the first network element and a device that hosts the source application.

11. A non-transitory computer-readable volatile or non-volatile storage medium as recited in claim 7, wherein receiving the one or more data packets comprises intercepting the one or more data packets at the first network element, and wherein the one or more data packets are destined for a destination application rather than the first network element.

12. A non-transitory computer-readable volatile or non-volatile storage medium as recited in claim 7, wherein the first network element is a network switch or router.

13. An apparatus for providing reliable delivery of an application layer message, comprising:
a network interface for receiving one or more packet flows;
a processor;
a computer-readable volatile or non-volatile storage medium storing one or more stored sequences of instructions which, when executed by the processor, cause the processor to carry out the steps of:
receiving one or more data packets;
determining a first application layer message that is collectively contained in one or more payload portions of the one or more data packets, wherein the first application layer message originated at a source application;
extracting, from the first application layer message, a message identifier that is contained in the first application layer message;
determining whether a message identifier queue contains the message identifier; and
in response to determining that the message identifier queue does not contain the message identifier, storing the first application layer message in an application layer message queue from which a destination application can retrieve the first application layer message, and sending, toward the source application, an acknowledgment (ACK) message that indicates the message identifiers;
wherein the apparatus is located between the source application and a destination of the first application layer message.

14. An apparatus as recited in claim 13, wherein the one or more stored sequences of instructions further comprise instructions which, when executed by the processor, cause the processor to:
identifier perform the storing in a persistent storage device that is coupled to the router and coupled to the destination.

15. An apparatus as recited in claim 13, wherein the one or more stored sequences of instructions further comprise instructions which, when executed by the processor, cause the processor to:
in response to determining that the message identifier queue contains the message identifier, sending the acknowledgment (ACK) message toward the source application without storing the first application layer message in the application layer message queue.

16. An apparatus as recited in claim 13, wherein the message identifier was added to the first application layer message by a second network element that is separate from both the first network element and a device that hosts the source application.

17. An apparatus as recited in claim 13, wherein receiving the one or more data packets comprises intercepting the one or more data packets at the first network element, and wherein the one or more data packets are destined for a destination application rather than the first network element.

18. An apparatus as recited in claim 13, wherein the first network element is a network switch or router.