Method and apparatus for reducing overhead on a proxied connection

• US 6,006,268 A
• Filed: 07/31/1997
• Issued: 12/21/1999
• Est. Priority Date: 07/31/1997
• Status: Expired due to Term

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Coile, Brantley W., Howes, Richard A., LeBlanc, William M.
• Primary Examiner(s): Maung, Zarni
• Assistant Examiner(s): Najjar, Saleh
• Application Number:
  US08/903,823
• Time in Patent Office: 873 Days
• Field of Search: 395/200.32, 395/200.33, 395/200.42, 395/200.49, 395/200.54, 395/200.57, 395/200.58, 709/202, 709/203, 709/212, 709/219, 709/224, 709/227, 709/228
• US Class Current: 709/227
• CPC Class Codes: H04L 1/16 in which the return channel carries supervisory signals, e.g. repetition request signals
• CPC Class Codes: H04L 2001/0092 Error control systems characterised by the topology of the transmission link
• CPC Class Codes: H04L 67/01 Protocols
• CPC Class Codes: H04L 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
• CPC Class Codes: H04L 69/163 In-band adaptation of TCP data exchange; In-band control procedures
• CPC Class Codes: H04L 69/326 in the transport layer [OSI layer 4] H04L69/16 takes precedence
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A system and method are disclosed for bypassing a participating application that receives data from a client connection between a proxy and a client and receives data from a server connection between a proxy and a server is disclosed. The method includes deriving a client originated packet sequence synchronization factor. The client originated packet sequence synchronization factor is derived from the difference between a last data sequence number sent by the participating application to the server and a last data acknowledgment number sent by the participating application to the client. A server originated packet sequence synchronization factor is derived from the difference between a last data sequence number sent by the participating application to the client and a last data acknowledgment number sent by the participating application to the server. A server originated data sequence number of a packet sent from the server to the client is adjusted using the server originated packet sequence synchronization factor. A client originated the data acknowledgment number of a packet sent from the client to the server is adjusted using the server originated packet sequence synchronization factor. A client originated data sequence number of a packet sent from the client to the server is adjusted using the client originated packet sequence synchronization factor. A server originated data acknowledgment number of a packet sent from the server to the client is adjusted using the client originated packet sequence synchronization factor. As a result, the data sequence and acknowledgment numbers are synchronized between the client and the server.

Claims

1. A method of reducing overhead on a proxied connection between a client and a server comprising:

receiving incoming data packets from a client on a client side and from a server on a server side, wherein the incoming data packets are associated with a proxied connection between the client and the server;

processing the incoming data packets with a participating application and relaying data derived from the incoming data packets from the client side to the server side and from the server side to the client side by generating outgoing data packets;

determining that the proxied connection is a suitable connection to be unproxied;

determining that all outgoing data packets have been acknowledged; and

routing subsequent incoming data packets for the proxied connection to a nonparticipating application wherein the nonparticipating application relays client originated incoming data packets from the client side to the server side and relays server originated incoming data packets from the server side to the client side.

2. A method as recited in claim 1 wherein the participating application participates in the TCP protocol and the nonparticipating application does not participate in the TCP protocol.

3. A method as recited in claim 1 wherein the nonparticipating application does not acknowledge incoming packets.

4. A method as recited in claim 1 wherein the nonparticipating application does not check the checksum of incoming packets.

5. A method as recited in claim 1 wherein the incoming packets from the client side have a client sequence number and a client acknowledgment number and wherein the incoming packets from the server side have a server sequence number and a server acknowledgment number and wherein the nonparticipating application applies a client originated packet sequence synchronization factor to the client sequence number so that the client sequence number corresponds to the sequence number of the next packet expected by the server.

6. A method as recited in claim 5 wherein the client originated packet sequence synchronization factor is derived from the difference between the last data sequence number sent by the participating application to the server and the last data acknowledgment number sent by the participating application to the client.

7. A method as recited in claim 1 wherein the incoming packets from the server side have a server sequence number and a server acknowledgment number and wherein the incoming packets from the client side have a client sequence number and a client acknowledgment number and wherein the nonparticipating application applies a server originated packet sequence synchronization factor to the server sequence number so that the server sequence number corresponds to the sequence number of the next packet expected by the client.

8. A method as recited in claim 7 wherein the server originated packet sequence synchronization factor is derived from the difference between the last data sequence number sent by the participating application to the client and the last data acknowledgment number sent by the participating application to the server.

9. A method as recited in claim 1 wherein the incoming data packets include packet headers having data checksums and IP checksums and wherein the data checksums and IP checksums are incremented and not checked by the nonparticipating application.

10. A method as recited in claim 1 further including defining a connection object including a quad, the quad including a client IP address, a server IP address, a client port number, and a server port number wherein the connection object is used to modify packet headers in the nonparticipating application.

11. A method as recited in claim 10 wherein the connection object further includes a client originated packet sequence synchronization factor and a server originated packet sequence synchronization factor wherein the client originated packet sequence synchronization factor is derived from the difference between the last data sequence number sent by the participating application to the server and the last data acknowledgment number sent by the participating application to the client and the server originated packet sequence synchronization factor is derived from the difference between the last data sequence number sent by the participating application to the client and the last data acknowledgment number sent by the participating application to the server.