Abstract:
A system and method for improving TCP performance in a L2 tunneling environment by snooping TCP/IP packets from the tunnel interface, terminating TCP locally and proxying TCP data in separate TCP connections. In particular, the system and method detects an encapsulated outgoing packet utilizing a Layer 2 tunneling protocol, processes a Point to Point Protocol layer in the outgoing packet to establishing Layer 2 tunneling protocol for a connection. The system and method also removes the Point to Point Protocol layer from the outgoing packet and inspects the outgoing packet for TCP information in the packet. The system and method forwards the outgoing packet to a locally driven application protocol path if TCP information is present, wherein the outgoing packet is encapsulated in association with the application protocol path.

Description:
TECHNOLOGICAL FIELD 
     This technology generally relates to improving network efficiency and in particular, to a system and method for improving TCP performance in network access with driver initiated application tunnel. 
     BACKGROUND 
     The common implementation of achieving network (L3) connectivity in SSL-VPN is to encapsulate data from the network layer (e.g. IP datagrams) with some link (L2) layer protocol and send data from L2 (e.g. PPP frames) over a SSL/TLS connection. Most, if not all, SSL-VPN vendors encounter poor performance when sending data through their SSL-VPN tunnels due to head of line blocking (when multiple L3 traffic are encapsulated within a SSL/TLS connection and loss occurs, TCP that transports the SSL/TLS connection must recover from loss and during recovery other encapsulated L3 traffic whose data not affected by the loss will not be sent. Datagram Transport Layer Security (DTLS), which uses UDP (User Datagram Protocol) as the transport instead of TCP, is used as an alternative to SSL/TLS-in SSL-VPN to avoid head of line blocking problem. However, the compression ratio achievable on a DTLS-based VPN tunnel is not as effective as that of the SSL/TLS-based VPN tunnel, since the compression history is limited to the maximum segment size of a DTLS packet, thereby resulting in potential loss. In comparison, SSL/TLS-based VPN tunnels provide for a larger compression history, thereby achieving a higher compression ratio. 
     Tunneling data from L3 within L2 over a secure connection (regardless SSL/TLS or DTLS) carries a number of disadvantages, in particular, tunneling data from one source endpoint to another destination endpoint incurs the overhead from these two layers (L2 and L3), which can be substantial. 
     SUMMARY 
     In an aspect, a method comprises detecting an encapsulated outgoing data packet utilizing a Layer 2 protocol. The method includes processing a Point to Point Protocol layer in the outgoing packet for establishing a connection to a VPN tunnel for the data packet. The method includes removing the Point to Point Protocol layer from the outgoing data packet. The method includes inspecting the outgoing data packet for TCP information in the data packet and processing the outgoing data packet in accordance with a locally driven application protocol path if TCP information is present the data packet, wherein the outgoing data packet is encapsulated in association with the application protocol path. 
     In an aspect, a machine readable medium having stored thereon instructions, comprising machine executable code which when executed by at least one machine, causes the machine to detect an encapsulated outgoing data packet utilizing a Layer 2 driver. The code causes the machine to process a Point to Point Protocol layer in the outgoing data packet for establishing Layer 2 tunneling to a VPN connection. The code causes the machine to remove the Point to Point Protocol layer from the outgoing data packet. The code causes the machine to inspect the outgoing data packet for TCP information. The code causes the machine to forward the outgoing data packet to a locally driven application protocol path if TCP information is present in the data packet, wherein the outgoing data packet is encapsulated in association with the application protocol path. 
     In an aspect, a client device comprises a network interface for detecting an encapsulated outgoing data packet utilizing a Layer 2 driver. The client device includes a controller for processing a Point to Point Protocol layer in the outgoing data packet for establishing Layer 2 tunneling to a VPN connection. The controller removes the Point to Point Protocol layer from the outgoing data packet and inspects the outgoing data packet for TCP information in the packet. The controller is configured to forward the outgoing data packet to a locally driven application protocol path via the network interface if TCP information is present, wherein the outgoing data packet is encapsulated in association with the application protocol path. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram of an example system environment that improves TCP performance over a VPN configuration; 
         FIG. 2  is a block diagram of a client device shown in  FIG. 1 ; 
         FIG. 3A  is a schematic of a data packet encapsulated for according to a L2 Tunneling Protocol in accordance with an aspect of the present disclosure; 
         FIG. 3B  is a schematic of a data packet encapsulated for according to a L7 Tunneling Protocol in accordance with an aspect of the present disclosure; 
         FIG. 4A  is a schematic of an data packet encapsulated to have an access protocol component in accordance with an aspect of the present disclosure; 
         FIG. 4B  is a schematic of an data packet encapsulated to have a L7 application component in accordance with an aspect of the present disclosure; 
         FIG. 5  is an example flow chart diagram depicting portions of processes for improving TCP performance in network access packets using a driver initiated application tunneling component in accordance with an aspect of the present disclosure. 
     
    
    
     While these examples are susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail preferred examples with the understanding that the present disclosure is to be considered as an exemplification and is not intended to limit the broad aspect to the embodiments illustrated. 
     DETAILED DESCRIPTION 
       FIG. 1  illustrates a example system environment  100  includes one or more servers  102  operating a secure network domain, whereby one or more servers  102  are configured to run a Virtual Private Network (VPN) software. The system environment includes one or more client devices  106  and one or more traffic management devices  110 , although the environment  100  could include other numbers and types of devices in other arrangements. 
     The network traffic management device  110  is coupled to the servers  102  via local area network (LAN)  104  and client devices  106  via network  108 . Generally, requests sent over the network  108  from client devices  106  towards servers  102  are received by traffic management device  110 . 
     Client devices  106  comprise computing devices capable of connecting to other computing devices, such as network traffic management device  110 , thereby indirectly connecting with the servers over a VPN connection. Such connections are performed over wired and/or wireless networks, such as network  108 , to send and receive data, such as for Web-based and non Web-based requests, receiving responses to requests and/or performing other tasks, in accordance with the processes described below in connection with the present disclosure. Non-limiting and non-exhausting examples of such devices include personal computers (e.g., desktops, laptops), mobile and/or smart phones and the like. 
     In an example, client devices  106  run Web browsers that may provide an interface for operators, such as human users, to interact with for making requests for resources to different web server-based applications or Web pages via the network  108 , although other server resources may be requested by clients. One or more Web-based applications may run on the web application server  102  that provide the requested data back to one or more exterior network devices, such as client devices  106 . One or more of the client devices also include client side software which allows the client device  106  to connect to the secure network using a VPN tunneling connection. 
     Network  108  comprises a publicly accessible network, such as the Internet, which includes client devices  106 . However, it is contemplated that the network  108  may comprise other types of private and public networks that include other devices. Communications, such as requests from clients  106  and responses from servers  102 , take place over the network  108  according to standard network protocols, such as the HTTP and TCP/IP protocols in this example. However, the principles discussed herein are not limited to this example and can include other protocols. Further, it should be appreciated that network  108  may include local area networks (LANs), wide area networks (WANs), direct connections and any combination thereof, as well as other types and numbers of network types. On an interconnected set of LANs or other networks, including those based on differing architectures and protocols, routers, switches, hubs, gateways, bridges, and other intermediate network devices may act as links within and between LANs and other networks to enable messages and other data to be sent from and to network devices. Also, communication links within and between LANs and other networks typically include twisted wire pair (e.g., Ethernet), coaxial cable, analog telephone lines, full or fractional dedicated digital lines including T1, T2, T3, and T4, Integrated Services Digital Networks (ISDNs), Digital Subscriber Lines (DSLs), wireless links including satellite links and other communications links known to those skilled in the relevant arts. In essence, the network  108  includes any communication method by which data may travel between client devices  106 , servers  102  and network traffic management device  110 , and the like. 
     LAN  104  comprises a private local area network that includes the network traffic management device  110  coupled to the one or more servers  102 , although the LAN  104  may comprise other types of private and public networks with other devices. Networks, including local area networks, besides being understood by those skilled in the relevant arts, have already been generally described above in connection with network  108  and thus will not be described further. 
     The one or more servers  102  comprise one or more server computing machines capable of operating one or more Web-based applications as well as one or more VPN tunneling applications that may be accessed by network devices in the network  108 . Such network devices include client devices  106 , via the network traffic management device  110 , and may provide other data representing requested resources, such as particular Web page(s), image(s) of physical objects, and any other objects, responsive to the requests. It should be noted that the server  102  may perform other tasks and provide other types of resources. It should be noted that while only two servers  102  are shown in the environment  100  depicted in  FIG. 1 , other numbers and types of servers may be coupled to the network traffic management device  110 . It is also contemplated that one or more of the servers  102  may be a cluster of servers managed by the network traffic management device  110 . It is also contemplated that the client devices  106  may connect to the servers  102  using a VPN connection without the use of the network traffic management device  110 . 
     As per the TCP/IP protocols, requests from the requesting client devices  106  may be sent as one or more streams of data packets over network  108  to the network traffic management device  110  and/or the servers  102  over a VPN connection. Such protocols can establish connections, send and receive data for existing connections, and the like. It is to be understood that the one or more servers  102  may be hardware and/or software, and/or may represent a system with multiple servers that may include internal or external networks. In this example, the servers  102  may be Web application servers such as Microsoft® IIS servers or Apache® servers, although other types of servers may be used. Further, additional servers may be coupled to the network  108  and many different types of applications may be available on servers coupled to the network  108 . 
     Each of the servers  102  and client devices  106  may include one or more central processing units (CPUs), one or more computer readable media (i.e., memory), and interface systems that are coupled together by internal buses or other links as are generally known to those of ordinary skill in the art. 
     As shown in the example environment  100  depicted in  FIG. 1 , the network traffic management device  110  is interposed between client devices  106  in network  108  and the servers  102  in LAN  104 . Again, the environment  100  could be arranged in other manners with other numbers and types of devices. Also, the network traffic management device  110  is coupled to network  108  by one or more network communication links and intermediate network devices (e.g. routers, switches, gateways, hubs and the like) (not shown). It should be understood that the devices and the particular configuration shown in  FIG. 1  are provided for exemplary purposes only and thus are not limiting. 
     Generally, the network traffic management device  110  manages network communications, which may include one or more client requests and server responses, from/to the network  108  between the client devices  106  and one or more of the servers  102  in LAN  104 . These requests may be destined for one or more servers  102 , and may take the form of one or more TCP/IP data packets originating from the network  108 . In an aspect, the requests pass through one or more intermediate network devices and/or intermediate networks, until they ultimately reach the traffic management device  110 . In any case, the network traffic management device  110  may manage the network communications by performing several network traffic related functions involving the communications. Such functions include load balancing, access control, and validating HTTP requests using JavaScript code that are sent back to requesting client devices  106  in accordance with the processes described herein. 
     Referring now to  FIG. 2 , an example client device  106  includes a device processor  200 , device I/O interfaces  202 , network interface  204  and device memory  218 , which are coupled together by bus  208 . It should be noted that the device  110  could include other types and numbers of components. 
     Device processor  200  comprises one or more microprocessors configured to execute computer/machine readable and executable instructions stored in device memory  218 . Such instructions implement network traffic management related functions of the client device  106 . In addition, the instructions implement the application module  210  to perform one or more portions of the processes illustrated in  FIG. 3 . It is understood that the processor  200  may comprise other types and/or combinations of processors, such as digital signal processors, micro-controllers, application specific integrated circuits (“ASICs”), programmable logic devices (“PLDs”), field programmable logic devices (“FPLDs”), field programmable gate arrays (“FPGAs”), and the like. The processor is programmed or configured according to the teachings as described and illustrated in the present disclosure. 
     Device I/O interfaces  202  comprise one or more user input and output device interface mechanisms. The interface may include a computer keyboard, mouse, display device, and the corresponding physical ports and underlying supporting hardware and software to enable the client device  106  to communicate with the outside environment. Such communication may include accepting user data input and to provide user output, although other types and numbers of user input and output devices may be used. Additionally or alternatively, as will be described in connection with network interface  204  below, the client device  106  may communicate with the outside environment for certain types of operations (e.g., configuration) via a network management port. 
     Network interface  204  comprises one or more mechanisms that enable the client device  106  to engage in TCP/IP communications over LAN  104  and network  108 . However, it is contemplated that the network interface  204  may be constructed for use with other communication protocols and types of networks. Network interface  204  is sometimes referred to as a transceiver, transceiving device, or network interface card (NIC), which transmits and receives network data packets to one or more networks, such as LAN  104  and network  108 . In an example where the client device  106  includes more than one device processor  200  (or a processor  200  has more than one core), each processor  200  (and/or core) may use the same single network interface  204  or a plurality of network interfaces  204 . Further, the network interface  204  may include one or more physical ports, such as Ethernet ports, to couple the network traffic management device  110  with other network devices, such as servers  102 . Moreover, the interface  204  may include certain physical ports dedicated to receiving and/or transmitting certain types of network data, such as device management related data for configuring the client device  106 . 
     Bus  208  may comprise one or more internal device component communication buses, links, bridges and supporting components, such as bus controllers and/or arbiters. The bus enable the various components of the network traffic management device  110 , such as the processor  200 , device I/O interfaces  202 , network interface  204 , and device memory  218 , to communicate with one another. However, it is contemplated that the bus may enable one or more components of the client device  106  to communicate with components in other devices as well. Example buses include HyperTransport, PCI, PCI Express, InfiniBand, USB, Firewire, Serial ATA (SATA), SCSI, IDE and AGP buses. However, it is contemplated that other types and numbers of buses may be used, whereby the particular types and arrangement of buses will depend on the particular configuration of the network traffic management device  110 . 
     Device memory  218  comprises computer readable media, namely computer readable or processor readable storage media, which are examples of machine-readable storage media. Computer readable storage/machine-readable storage media may include volatile, nonvolatile, removable, and non-removable media implemented in any method or technology for storage of information. Such storage media contains computer readable/machine-executable instructions, data structures, program modules, or other data, which may be obtained and/or executed by one or more processors, such as device processor  200 . Such instructions allow the processor to perform actions, including implementing an operating system for controlling the general operation of the client device  106  to perform one or more portions of the process described herein. 
     Examples of computer readable storage media include RAM, BIOS, ROM, EEPROM, flash/firmware memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information. Such desired information includes data and/or computer/machine-executable instructions and which can be accessed by a computing or specially programmed device, such as client device  106 . 
     Security module  210  is depicted in  FIG. 2  as being within memory  218  for exemplary purposes only; it should be appreciated the module  210  may be alternatively located elsewhere. Generally, when instructions embodying the application module  210  are executed by the device processor  200 . The security module  210  also uses additional information obtained by further analyzing collected data to identify latencies associated with particular servers, server applications or other server resources, page traversal rates, client device fingerprints and access statistics. 
     Furthermore, each of the devices of the system  100  may be conveniently implemented using one or more general purpose computer systems, microprocessors, digital signal processors, micro-controllers, application specific integrated circuits (ASIC), programmable logic devices (PLD), field programmable logic devices (FPLD), field programmable gate arrays (FPGA) and the like. The devices may be programmed according to the teachings as described and illustrated herein, as will be appreciated by those skilled in the computer, software, and networking arts. 
     In addition, two or more computing systems or devices may be substituted for any one of the devices in the system  100 . Accordingly, principles and advantages of distributed processing, such as redundancy, replication, and the like, also can be implemented, as desired, to increase the robustness and performance of the devices and systems of the system  100 . The system  100  may also be implemented on a computer system or systems that extend across any network environment using any suitable interface mechanisms and communications technologies including, for example telecommunications in any suitable form (e.g., voice, modem, and the like), Public Switched Telephone Network (PSTNs), Packet Data Networks (PDNs), the Internet, intranets, a combination thereof, and the like. 
       FIG. 3A  illustrates a schematic of a data packet which is encapsulated as a tunneling mechanism and has routing information defined by a Layer 3 (L3) to be sent over a VPN connection In particular, the packet  300  contains data  99  which is encapsulated for L3 communications with L3 header information including a first TCP layer  302  and a first IP layer  304 , which serve to encapsulate the data and form an IP datagram. In addition, the packet is further encapsulated with a L2 protocol data link layer, such as a PPP header  306 , which is used as a driver to form the tunnel by which the data  99  is to be transmitted to the VPN connection. Further, the packet  300  includes a SSL encryption tunnel which comprises an SSL layer  308 , a second TCP layer  310 , and a second IP layer  312 . The packet illustrated in  FIG. 3A  is designated herein as a network access packet  300 , although it is not limited to the designated name. In an aspect, the network access packet  300  may be referred to herein as a L2 tunneling protocol (L2TP). However, it is contemplated that the packet  300  may include additional and/or different layers as well as utilize other protocols and headers consistent with a L2 protocol, and is thus not limited to the particular configuration of L2TP. Additionally, it should be noted that although PPP is discussed herein, other data link protocols are contemplated for use with the present system and method. 
     As stated above, the network access packet  300  is versatile and robust and can reliably transmit different types of communications. In addition, the network access packet  300  is able to support compression techniques which are more effective and is generally more accepted in the networking realm. However, as stated above, the network access packet  300  has significant disadvantages due to it having multiple TCP layers and substantial overhead as well as potential head of the line blocking issues. 
       FIG. 3B  illustrates a schematic of a data packet which is encapsulated and prepared for transmission to a destination entity (e.g. server, another client device and the like) using a L7 tunneling protocol. As shown in  FIG. 3B , the encapsulated packet  300 ′ contains data  99  which is packetized with a layer 7 (L7) header  301  which spans packets and provides routing information to identify where the data is to be sent. The packet  300 ′ includes a SSL encryption layer  308 ′, a TCP layer  310 ′, and an IP layer  312 ′. The packet  300 ′ illustrated in  FIG. 3B  is designated herein as an application tunnel, although it is not limited to the designated name. In addition, the network access packet  300 ′ may include additional and/or different layers, and is thus not limited to the particular configuration shown in  FIG. 3B . 
     Unlike the L2TP packet  300  in  FIG. 3A , the application tunnel packet  300 ′ carries substantially less overhead by way of utilizing the L7 header  301  and only one TCP layer  310 ′ and IP layer  312 ′. Additionally, the L7 header  301  provides destination information for the data  99  which are associated with the IP layer  312 ′. Further, the L7 header  301  spans among multiple packets, thereby requiring that it only be used once for a communication session or flow, instead of per packet as with the network access packet  300  in  FIG. 3A . Thus, once the application tunnel  300 ′ is established, data  99  is passed along the tunnel without having to encapsulate each data  99  in a communication session. Additionally, the application tunnel  300 ′ is DNS based driver which points to a locally listening process on the client device  106 , such as a virtual server located on the client device  106 . This allows the client device  106  to locally establish the tunnel via the ports on the client device  106 . In other words, the network interface of the VPN software on the client device  106  provides a virtual tunnel to allow access to the actual VPN tunnel between the client device and the VPN software running on server  102 . This translates into a faster, more effective tunneling protocol, when compared to the L2TP described in  FIG. 3A , for transmitting TCP based packets to the destination entity. 
     However, data encapsulated using the application tunnel protocol  300 ′ also has various disadvantages compared to the L2 tunneling protocol. For instance, the application tunnel  300 ′ can only be used for TCP applications, and is thus not as versatile as the network access  300 . In contrast, the network access  300  is more flexible as it has better ability to route the packet. 
       FIGS. 4A-4B  illustrate schematics of encapsulated packets in accordance with an aspect of the present disclosure. In particular, the present disclosure makes use of selectively using two different protocol component paths to effectively improve performance of TCP based packets sent over a VPN connection. In particular,  FIG. 4A  illustrates a L2 based access protocol path  402  whereas  FIG. 4B  illustrates a L7 based application protocol path  404 . The access protocol path  402  shown in  FIG. 4A  includes data  99  which is encapsulated with a first IP layer  406  and a security layer  408 . In an aspect, the security layer  408  can be configured to include UDP and DTLS based protocols. In an aspect, the security layer  408  can be configured to utilize an IPsec based protocol. It should be noted that although UDP+DTLS and IPSec protocols are discussed herein, other appropriate security protocols can be utilized in the security layer  408 . The packet  402  also includes an IP layer  418  which encapsulates the security layer  408 . It should be noted that the access protocol path  402  may include additional and/or different layers consistent with a L2 protocol, and is thus not limited to the particular configuration shown in  FIG. 4A . 
     The application protocol path  404  shown in  FIG. 4B  includes data  99  that is encapsulated with an L7 header  410  as well as an SSL layer  412  and a TCP layer  414 , as shown in  FIG. 4 . An IP layer  416  is contained in the packet and encapsulates the TCP layer  414 . It should be noted that the application component path  404  may include additional and/or different layers consistent with a L7 based protocol, and is thus not limited to the particular configuration path shown in  FIG. 4B . 
     As will be discussed in more detail below, software on the client device  106  receives data from a tunnel interface of the client device  106 , which is the local network interface of the client device  106  discussed above. The VPN software includes a protocol parser which is deployed within the client device  106  to recognize frame boundaries of the outgoing encapsulated data packet at the network interface. In particular, the protocol parser inspects the frame boundaries of the packet, such as the Network Access Protocol in  FIG. 3A , and in particular the L2 PPP layer  306  to determine if the PPP layer encapsulates TCP/IP packet layers  302 ,  304 . If TCP/IP layers are present in the data packet, the software in the client device  106  will process the packet to be transmitted in accordance with the application protocol path  404  through the VPN tunnel. In other words, the application component path  404  effectively acts as a TCP/IP proxy where the TCP connection is forwarded to the VPN tunnel using the application protocol path  404 . This is done by the software on the client device  106  which effectively de-encapsulates the network access packet  300  and separates the TCP/IP layers and the data from the rest of the packet, whereby the TCP/IP layers and data is encapsulated in accordance with the access component path  404 . The modified packet is then sent through the VPN tunnel. 
     In an aspect, prior to the data being sent over the application configuration path  404 , the packet is processed to modify the network address information in the IP packet headers to point to the local process of the client device  106 . As stated above, the application configuration path  404  is locally run the client device  106 . Thus, the packet is subject to a network address translation process to properly point the packet to the local driver to ensure that the packet is routed properly. 
       FIG. 5  is an example flow chart diagram depicting portions of processes for improving TCP performance in network access packets using a driver initiated application tunneling component. As shown in  FIG. 5 , a client device  106  connects to a wide area network  108  or LAN  104  using a VPN connection (block  500 ). Upon the client device  106  sending an encapsulated data packet, such as  300  or  300 ′, the software on the client device  106  effectively snoops the outgoing packet using a protocol parser and inspects the L2 tunnel interface and the PPP header information to determine routing information of the packet (block  502 ). Thereafter, the software removes the PPP header information from the packet as it is no longer needed (block  504 ). Thereafter software on the client device  106  snoops the data packet to determine whether the packet includes TCP/IP layers (block  506 ). If there are no TCP/IP layers in the packet, the software encapsulates the data in accordance with the protocols of the access protocol component  404  (block  508 ). The access configured encapsulated packet is then sent to the VPN tunnel (block  510 ). 
     In contrast, if the software on the client device  106  detects that TCP/IP layers are present in the outgoing packet, the software separates the frame/datagram from the data path of the network access packet  300  and forwards it to the application component  404  (block  512 ). As stated above, in an aspect, the packet undergoes a network address translation process to ensure that the packet is routed locally through the client device  106 . Thereafter, the TCP connection is terminated locally on the client device  106  and the data is forwarded to the destination entity using the TCP tunnel provided via the application component  404 , one per new TCP flow (block  514 ). 
     In the reverse direction, when an encapsulated data packet is to be sent to the client device  106 . The network traffic management device  110  forwards the data packet sent from the server  102  to the corresponding TCP application tunnel which was used to initially send the data packet from the client device  106 . Upon receiving the data packet, the software on the client device  106  reads the data from the TCP application tunnel and returns it to the application component  404 . The application component  404  then adds the TCP/IP headers and encapsulates the IP datagram into a format consistent to the tunnel interface before forwarding the frame/datagram to the tunnel interface. 
     Having thus described the basic concepts, it will be rather apparent to those skilled in the art that the foregoing detailed disclosure is intended to be presented by way of example only, and is not limiting. Various alterations, improvements, and modifications will occur and are intended to those skilled in the art, though not expressly stated herein. These alterations, improvements, and modifications are intended to be suggested hereby, and are within the spirit and scope of the examples. Additionally, the recited order of processing elements or sequences, or the use of numbers, letters, or other designations therefore, is not intended to limit the claimed processes to any order except as may be specified in the claims.