Packet retransmission eliminator

• US 6,266,337 B1
• Filed: 06/23/1998
• Issued: 07/24/2001
• Est. Priority Date: 06/23/1998
• Status: Expired due to Term

• Current Assignee: Riverbed Technology Incorporated
• Original Assignee: Expand Networks Incorporated
• Inventors: Marco, Talmon
• Primary Examiner(s): Patel, Ajit
• Assistant Examiner(s): PHUNKULH, BOB A
• Application Number:
  US09/103,621
• Time in Patent Office: 1,127 Days
• Field of Search: 370/229, 370/230, 370/231, 370/235, 370/236, 370/389, 370/400, 370/401, 370/410, 370/352, 370/477, 714/748
• US Class Current: 370/410
• CPC Class Codes: H04L 1/1829 Arrangements specially adapted for the receiver end
• CPC Class Codes: H04L 1/1867 Arrangements specially adapted for the transmitter end
• CPC Class Codes: H04L 2001/0092 Error control systems characterised by the topology of the transmission link
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/193 at the transport layer, e.g. TCP related

Abstract

A packet retransmission eliminator is installed on opposite ends of a path in a network. Each original packet sent over the path is cached on the transmitting and the receiving ends of the path. Retransmitted packets that are to be sent over the path are intercepted and replaced with a substitute retransmission packet. In response to a received retransmission packet, the receiving end retransmits the original packet using the corresponding packet that was previously stored in the cache.

Claims

1. A method of reducing data retransmissions over a path defined within a network, the method comprising the steps of:

receiving, at a first end of the path, a packet to be transmitted to an opposite end of the path;

determining by means of a first comparator whether said packet has previously been transmitted to said opposite end of the path;

if said packet has not previously been transmitted, storing data of said packet in at least two data memories, a first data memory at said first end of the path and a second data memory at said opposite end of the path; and

if said packet has previously been transmitted, employing a first packet routing controller, at said first end of the path, for sending a retransmission message instead of said packet to said opposite end of the path and

similarly employing a second packet routing controller, at said opposite end of the path, to send previously stored packet data from said second of said at least two data memories to said opposite end of the path in response to said retransmission message thereby reducing data retransmissions.

2. The method of claim 1 further including the step of sending said packet to another end of the path if said packet has not previously been transmitted.

3. The method of claim 1 further including the steps of receiving said packet at the other end of the path and determining whether the packet received at the other end of the path is associated with the retransmission message.

4. The method of claim 3 further including the step of routing the packet received at the other end of the path in the event the packet received at the other end of the path is not associated with said a retransmission message.

5. The method of claim 1 wherein said step of storing includes the step of storing information associated with said packet in a data memory.

6. The method of claim 5 wherein the information comprises a checksum.

7. The method of claim 5 wherein the information comprises data from the packet.

8. The method of claim 1 wherein the determining step includes comparing data associated with the packet with data stored in a data memory.

9. The method of claim 8 wherein the data associated with the packet and the data stored in said data memory comprise checksums.

10. The method of claim 8 wherein the data associated with the packet and the data stored in said data memory comprise data from the packet.

11. The method of claim 1 wherein said retransmission message comprises a retransmission packet which comprises information that identifies said previously transmitted packet.

12. The method of claim 1 wherein the network comprises an IP-based network.

13. The method of claim 12 wherein the path comprises an IP hop.

14. A system for reducing data retransmissions over a path defined within a network, the system comprising:

a network interface for receiving, at one end of the path, a packet to be transmitted to an opposite end of the path;

a first comparator for determining whether said packet has previously been transmitted;

a first data memory for storing packet data if said packet has not previously been transmitted;

a first packet routing controller, at one end of the path, for sending a retransmission message instead of said packet to the opposite end of the path is said packet has previously been transmitted;

a second data memory at said opposite end of the path for storing packet data in the event said packet has not previously been transmitted; and

a second packet routing controller, at said opposite end of the path, for sending packet data from the second data memory in response to the retransmission message.

15. The system of claim 14 wherein said first packet routing controller sends the packet to another end of the path if said packet has not previously been transmitted.

16. The system of claim 14 further comprising a second network interface for receiving said packet at the other end of the path and a second comparator for determining whether the packet received at the other end of the path is associated with the retransmission message.

17. The system of claim 16 wherein the second packet routing controller routes the packet received at the other end of the path in the event the packet received at the other end of the path is not associated with said retransmission message.

18. The system of claim 14 wherein the information comprises a checksum.

19. The system of claim 14 wherein the information comprises data from the packet.

20. The system of claim 14 wherein the first comparator compares data associated with the packet with data stored in the second data memory.

21. The system of claim 20 wherein the data associated with the packet and the data stored in the data second memory comprise checksums.

22. The system of claim 20 wherein the data associated with the packet and the data stored in the second data memory comprise data from the packet.

23. The system of claim 14 wherein said retransmission message comprises a retransmission packet which comprises information that identifies said previously transmitted packet.

24. The system of claim 14 wherein the network comprises an IP-based network.

25. The system of claim 24 wherein the path comprises an IP hop.