Network protocol with damage loss resilient congestion control algorithm

• US 7,821,937 B1
• Filed: 06/29/2007
• Issued: 10/26/2010
• Est. Priority Date: 06/29/2007
• Status: Active Grant

• Current Assignee: Veritas Technologies, LLC (Whitehouse Group Ltd.)
• Original Assignee: Symantec Corporation (NortonLifeLock Inc.)
• Inventors: Guo, Fanglu
• Primary Examiner(s): Vu; Huy D
• Assistant Examiner(s): BEYEN, ZEWDU A
• Application Number:
  US11/771,204
• Time in Patent Office: 1,215 Days
• Field of Search: None
• US Class Current: 370/232
• CPC Class Codes: H04L 43/0829 Packet loss
• CPC Class Codes: H04L 43/0852 Delays
• CPC Class Codes: H04L 43/0864 Round trip delays
• CPC Class Codes: H04L 43/16 Threshold monitoring

Abstract

Various embodiments of a network protocol that utilizes a congestion control algorithm that distinguishes between congestion loss and damage loss are described. In response to a packet loss on a network, a delay-based detection algorithm may be performed based on RTT (Round-Trip Time) information to determine whether the network is congested. If the delay-based detection algorithm does not determine that the network is congested then a consistency-based detection algorithm may be performed based on packet loss rate information. If either the delay-based detection algorithm or the consistency-based detection algorithm determine that the network is congested then the rate of data transmission may be reduced, e.g., by reducing a congestion window size.

Claims

1. A non-transitory computer-readable storage medium comprising program instructions executable to implement a method comprising:

determining a damage loss rate, wherein the damage loss rate indicates a loss rate of packets due to network transmission error and unrelated to network congestion, and wherein determining the damage loss rate comprises dividing a number of packets lost due to network transmission error by a number of packets transmitted over a network;

after determining the damage loss rate, sending a plurality of packets over the network;

detecting a plurality of packet losses among the plurality of packets sent over the network;

in response to each packet loss;

determining a respective recent packet loss rate, comprising, for the first packet loss, dividing a number of lost packets by a number of packets transmitted since transmission was started, and for a subsequent packet loss, dividing a number of lost packets by a number of packets transmitted since the previous recent packet loss rate was determined;

determining whether the respective recent packet loss rate is greater than the damage loss rate;

if the respective recent packet loss rate is greater than the damage loss rate, incrementing a counter;

if the respective recent packet loss rate is not greater than the damage loss rate, resetting the counter;

determining whether the counter exceeds a threshold value;

if the counter exceeds the threshold value, adjusting a rate of sending subsequent packets over the network; and

if the counter does not exceed the threshold value, maintaining the rate of sending subsequent packets over the network.

2. The non-transitory computer-readable storage medium of claim 1, wherein adjusting the rate of sending subsequent packets over the network comprises decreasing the rate.

3. The non-transitory computer-readable storage medium of claim 1, wherein adjusting the rate of sending subsequent packets over the network comprises increasing the rate.

4. The non-transitory computer-readable storage medium of claim 1, wherein the damage loss rate comprises a long-term damage loss rate.

5. The non-transitory computer-readable storage medium of claim 1, wherein adjusting the rate of sending subsequent packets over the network comprises adjusting a size of a congestion window.

6. A method comprising:

determining a damage loss rate, wherein the damage loss rate indicates a loss rate of packets due to network transmission error and unrelated to network congestion, and wherein determining the damage loss rate comprises dividing a number of packets lost due to network transmission error by a number of packets transmitted over a network;

after determining the damage loss rate, sending a plurality of packets over the network;

detecting a plurality of packet losses among the plurality of packets sent over the network;

in response to each packet loss;

determining a respective recent packet loss rate, comprising, for the first packet loss, dividing a number of lost packets by a number of packets transmitted since transmission was started, and for a subsequent packet loss, dividing a number of lost packets by a number of packets transmitted since the previous recent packet loss rate was determined;

determining whether the respective recent packet loss rate is greater than the damage loss rate;

if the respective recent packet loss rate is greater than the damage loss rate, incrementing a counter;

if the respective recent packet loss rate is not greater than the damage loss rate, resetting the counter;

determining whether the counter exceeds a threshold value;

if the counter exceeds the threshold value, adjusting a rate of sending subsequent packets over the network; and

if the counter does not exceed the threshold value, maintaining the rate of sending subsequent packets over the network.

7. The method of claim 6,

wherein adjusting the rate of sending subsequent packets over the network comprises decreasing the rate.

8. The method of claim 6,

wherein adjusting the rate of sending subsequent packets over the network comprises increasing the rate.

9. A system comprising:

one or more processors; and

memory storing program instructions;

wherein the program instructions are executable by the one or more processors to;

determine a damage loss rate, wherein the damage loss rate indicates a loss rate of packets due to network transmission error and unrelated to network congestion, and wherein determining the damage loss rate comprises dividing a number of packets lost due to network transmission error by a number of packets transmitted over a network;

after determining the damage loss rate, send a plurality of packets over the network;

detect a plurality of packet losses among the plurality of packets sent over the network;

in response to each packet loss;

determine a respective recent packet loss rate, comprising, for the first packet loss, dividing a number of lost packets by a number of packets transmitted since transmission was started, and for a subsequent packet loss, dividing a number of lost packets by a number of packets transmitted since the previous recent packet loss rate was determined;

determine whether the respective recent packet loss rate is greater than the damage loss rate;

if the respective recent packet loss rate is greater than the damage loss rate, increment a counter;

if the respective recent packet loss rate is not greater than the damage loss rate, reset the counter;

determine whether the counter exceeds a threshold value;

if the counter exceeds the threshold value, adjust a rate of sending subsequent packets over the network; and

if the counter does not exceed the threshold value, maintain the rate of sending subsequent packets over the network.