Method for minimizing unneeded retransmission of packets in a packet communication environment supporting a plurality of data link rates

• US 6,018,516 A
• Filed: 11/14/1997
• Issued: 01/25/2000
• Est. Priority Date: 11/14/1997
• Status: Expired due to Term

• Current Assignee: Gen Digital Inc.
• Original Assignee: Packeteer Incorporated (Gen Digital Inc.)
• Inventors: Packer, Robert L.
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): RAO, SEEMA SRINIVAS
• Application Number:
  US08/970,693
• Time in Patent Office: 802 Days
• Field of Search: 370/230, 370/253, 370/252, 370/400, 370/410, 370/428, 370/522, 370/231, 370/235, 370/236, 370/238, 714/748, 714/749, 714/18
• US Class Current: 370/231
• CPC Class Codes: H04L 1/1809 Selective-repeat protocols
• CPC Class Codes: H04L 1/188 Time-out mechanisms
• CPC Class Codes: H04L 1/1887 Scheduling and prioritising arrangements

Abstract

A method is provided for preventing gratuitous retransmission of data from being propagated through a network which includes holding data to be retransmitted for a minimum time period. If an acknowledgment occurs while the retransmitted data is still being held, then the retransmitted data is discarded rather than propagated through the network. The invention also provides for selectively holding retransmissions based upon ascertainable factors about the underlying connection activity, such as number of successful transmissions.

Claims

1. A method for minimizing retransmission of data on a transmission link in a digital data packet communication environment having a plurality of digital packet transmission stations interconnectable in arbitrary and changeable data paths, wherein said data packet communication environment lacks explicit end-to-end data rate control, said method comprising the steps of:

detecting retransmission of data at a point intermediate of said endpoints;

upon said detecting

clamping said retransmission of data to a clamp time, said clamp time being measured from a prerecorded time of original transmission of said data;

for said transmission of data, determining an elapsed time since said transmission; and

permitting said retransmission of data through said intermediate point whenever said elapsed time exceeds said clamp time without receipt of an acknowledgment.

2. The method of claim 1 further comprising the step of:

discarding said retransmission if said acknowledgment is received.

3. The method of claim 1 further comprising the step of:

removing a clamp of said retransmission of data whenever a number of consecutive transmissions without a timeout has occurred.

4. The method of claim 1 wherein said digital data packet communication environment is a Transmission Control Protocol (TCP) connection.

5. The method of claim 1 wherein said digital data packet communication environment is a User Datagram Protocol (UDP) session.

6. A method for preventing gratuitous retransmission of data from being propagated through a transmission link in a digital data packet communication environment having a plurality of digital packet transmission stations interconnectable in arbitrary and changeable data paths, wherein said data packet communication environment lacks explicit end-to-end data rate control, said method comprising the steps of;

detecting retransmission of data at a point intermediate of said endpoints;

upon said detecting

clamping data to be retransmitted for a minimum time period at a point intermediate of endpoints, said time period being measured from a prerecorded time of original transmission of said data;

waiting for an acknowledgment to occur while the retransmitted data is clamped;

discarding the data to be retransmitted if the acknowledgment occurs;

propagating the data to be retransmitted through the network via said intermediate point if the acknowledgment does not occur.

7. The method of claim 6 further comprising the step of:

selectively clamping the data to be retransmitted based upon ascertainable factors about the underlying connection activity.

8. The method of claim 6 further comprising the step of:

determining said minimum amount of time based upon ascertainable factors about the underlying connection activity.

9. The method of claim 6 wherein said digital data packet communication environment is a Transmission Control Protocol (TCP) connection.

10. The method of claim 6 wherein said digital data packet communication environment is a User Datagram Protocol (UDP) session.