System and method for improving transport protocol performance in communication networks having lossy links

• US 5,974,028 A
• Filed: 02/24/1997
• Issued: 10/26/1999
• Est. Priority Date: 02/24/1997
• Status: Expired due to Term

• Current Assignee: AT&T Intellectual Property I LP (AT&T, Inc.)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Ramakrishnan, Kadangode K.
• Primary Examiner(s): Vu, Huy D.
• Assistant Examiner(s): LEE, CHI HO A
• Application Number:
  US08/803,792
• Time in Patent Office: 974 Days
• Field of Search: 370/228, 370/230, 370/231, 370/232, 370/233-238, 370/242, 370/252, 370/253, 370/310, 370/312, 370/332, 370/333, 370/392, 370/394, 370/414, 370/415, 370/416, 370/417 , 370/444, 370/506, 371/30, 371/32, 371/33, 371/37.01, 371/37.7
• US Class Current: 370/229
• CPC Class Codes: H04L 1/1614 using bitmaps
• CPC Class Codes: H04L 1/1809 Selective-repeat protocols
• CPC Class Codes: H04L 1/1832 Details of sliding window management
• CPC Class Codes: H04L 1/1848 Time-out mechanisms
• CPC Class Codes: H04L 2001/125 Arrangements for preventing errors in the return channel
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/27 Evaluation or update of window size, e.g. using information derived from acknowledged [ACK] packets
• CPC Class Codes: H04L 47/31 by tagging of packets, e.g. using discard eligibility [DE] bits
• CPC Class Codes: H04L 47/32 by discarding or delaying data units, e.g. packets or frames
• 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 69/161 Implementation details of TCP/IP or UDP/IP stack architecture; Specification of modified or new header fields
• CPC Class Codes: H04L 69/163 In-band adaptation of TCP data exchange; In-band control procedures
• CPC Class Codes: H04W 28/0242 Determining whether packet losses are due to overload or to deterioration of radio communication conditions
• CPC Class Codes: H04W 28/0273 adapting protocols for flow control or congestion control to wireless environment, e.g. adapting transmission control protocol [TCP] wireless network protocols or protocol adaptations to wireless operation, e.g. wireless application protocol H04W80/00
• CPC Class Codes: H04W 28/10 Flow control between communication endpoints
• CPC Class Codes: H04W 8/04 Registration at HLR or HSS [Home Subscriber Server]
• CPC Class Codes: H04W 80/06 Transport layer protocols, e.g. TCP [Transport Control Protocol] over wireless transmission control protocol/Internet protocol [TCP/IP] or user datagram protocol [UDP] H04L69/16

Abstract

Providing transport protocol within a communication network having a lossy link. The receiver distinguishes between packets received with non-congestion bit errors and packets having been not at all received due to congestion. When packets are received with non-congestion bit errors, the receiver sends selective acknowledgments indicating that the packets were received with bit errors while suppressing duplicate acknowledgments to prevent the invocation of a congestion mechanism.

Claims

1. A method for providing transport protocol within a communication network having a lossy link connecting a receiver receiving a plurality of packets, each packet having a header including an address and a sequence number, comprising:

(a) distinguishing, for a first packet from the plurality of packets, an error from the group of a non-congestion bit error and congestion error; and

(b) when the first packet has non-congestion bit error, sending a selective acknowledgment indicating the first packet was received with non-congestion bit error while suppressing duplicate acknowledgments.

2. The method of claim 1, wherein step (a) further includes the substeps of:

(i) marking the first packet as having been received with a non-congestion bit error; and

(ii) passing the marked first packet to a software protocol.

3. The method of claim 1, further comprising:

(c) when the first packet has congestion, sending a duplicate acknowledgment indicating the first packet was not received due to congestion; and

(d) invoking a congestion control mechanism.

4. The method of claim 1, wherein step (b) is performed after a time out period expires.

5. The method of claim 1, wherein step (b) is performed after a subset of the plurality of packets is received.

6. The method of claim 5, wherein the subset is based on the congestion window size.

7. The method of claim 5, wherein the selective acknowledgment is a plurality of bits comprising a bit map indicating a status of each packet in the subset of packets.

8. The method of claim 7, wherein each bit of the selective acknowledgment corresponds to the sequence number of a packet, each bit has one value from the group of a first value indicating a packet was received with an error or a packet was not received, and a second value indicating a packet received without an error.

9. The method of claim 1, further comprising:

(c) retransmitting a packet not received or a packet received in error from a source to the receiver.

10. The method of claim 1, further comprising:

(c) providing forward error correction (FEC) to a header of each packet of the plurality.

11. The of method of claim 1, wherein the header for each packet includes a datalink header, an Internet protocol (IP) header, and a TCP header.

12. The method of claim 10, wherein the header for each packet includes a datalink header, an Internet protocol (IP) header, and a TCP header, and wherein forward error correction of step (c) is provided for the IP header and the TCP header.

13. The method of claim 12, wherein forward error correction of step (c) is provided by a base station being connected to the receiver over a lossy link.

14. The method of claim 1, wherein the transport protocol is transmission control protocol (TCP).

15. The method of claim 1, wherein the transport protocol is OSI TP4.

16. The method of claim 1, wherein the selective acknowledgment includes a flag bit having one value from the group of a first value indicating the first packet was received with an error, and a second value indicating the first packet was not received.

17. The method of claim 16, further comprising:

(c) sending the acknowledgment including the flag bit having the first value indicating the first packet was received with an error.

18. The method of claim 16, further comprising:

(c) sending the acknowledgment including the flag bit having the second value indicating the first packet was not received; and

(d) invoking a congestion control mechanism.

19. An apparatus for sending and receiving a plurality packets of information over a loss link, each packet having a header containing an address and a sequence number, within a communication network, comprising:

a means for identifying a first packet from the plurality of packets having a non-congestion error; and

a means sending a selective acknowledgment indicating the first packet was not completely received while suppressing duplicate acknowledgments.

20. The apparatus of claim 19, further comprising:

a means for identifying a second packet from the plurality of packets having not been received due to congestion;

a means for sending a duplicate acknowledgment indicating the second packet was not received due to congestion; and

a mean for invoking a congestion control mechanism.