Network Congestion Control with Awareness of Random Packet Losses

• US 20150029863A1
• Filed: 07/23/2013
• Published: 01/29/2015
• Est. Priority Date: 07/23/2013
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Lai, Cheng-Jia
• Granted Patent: US 9,485,186 B2
• Time in Patent Office: Days
• US Class Current: 370/237
• CPC Class Codes: H04L 43/0829 Packet loss
• CPC Class Codes: H04L 47/12 Avoiding congestion; Recovering from congestion
• CPC Class Codes: H04L 47/25 with rate being modified by the source upon detecting a change of network conditions
• 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 69/163 In-band adaptation of TCP data exchange; In-band control procedures
• CPC Class Codes: H04W 28/0236 radio quality, e.g. interference, losses or delay
• CPC Class Codes: H04W 28/0284 detecting congestion or overload during communication monitoring arrangements H04L43/00

Abstract

Messages are sent from a first network device to a second network device across a network. The network includes a network portion with an expected random packet loss rate. The actual packet loss rate for packets sent across the network is compared to the expected random packet loss rate. A determination is made that the actual packet loss rate is greater than the expected random packet loss rate. Compensation for network congestion is performed in response to the determination that the actual packet loss rate exceeds the expected random packet loss rate.

Claims

1. A method comprising:

sending messages from a first network device to a second network device across a network, wherein the network includes a network portion with an expected random packet loss rate;

comparing an actual packet loss rate of packets sent across the network to the expected random packet loss rate;

determining that the actual packet loss rate is greater than the expected random packet loss rate; and

compensating for network congestion in response to the determining.

2. The method of claim 1, wherein comparing the actual packet loss rate to the expected random packet loss rate comprises comparing an actual Layer 4 packet loss rate to an expected Layer 2 packet loss rate.

3. The method of claim 1, wherein compensating for network congestion comprises reducing a congestion window of the first network device.

4. The method of claim 1, wherein compensating for network congestion comprises reducing a slow-start threshold of the first network device.

5. The method of claim 1, further comprising fast retransmitting a lost packet from the first network device to the second network device.

6. The method of claim 1, further comprising receiving at the first device a message reporting the expected random packet loss rate of the network portion.

7. The method of claim 6, wherein receiving the message comprising receiving a locally generated message.

8. The method of claim 6, wherein receiving the message comprises receiving an out-of-band signaling message.

9. The method of claim 8, wherein receiving the out-of-band signaling message comprises receiving a plurality of messages from devices associated with a corresponding one of a plurality of network links, wherein each of the plurality of messages indicates an expected random packet loss rate for a respective network link.

10. The method of claim 1, further comprising manually configuring the first network device with the expected random packet loss rate.

11. The method of claim 1, further comprising dynamically calculating the actual packet loss rate at the first network device.

12. The method of claim 1, further comprising receiving a plurality of duplicate acknowledgement messages;

wherein comparing the actual packet loss rate to the expected random packet loss rate comprises comparing in response to receiving the plurality of duplicate acknowledgment messages.

13. The method of claim 1, wherein comparing the actual packet loss rate to the expected random packet loss rate comprises comparing the actual packet loss rate to the expected packet loss rate in response to expiration of a retransmission time-out timer.

14. The method of claim 1, wherein sending the messages from the first network device to the second network device comprises sending the messages across a wireless portion of the network.

15. An apparatus comprising:

a network interface unit configured to enable network communications;

a memory; and

a processor coupled to the network interface unit and the memory, wherein the processor is configured to;

send messages to a receiving network device across a network, wherein the network includes a network portion with an expected random packet loss rate;

compare an actual packet loss rate of packets sent across the network to the expected random packet loss rate;

determine that the actual packet loss rate is greater than the expected random packet loss rate; and

compensate for network congestion in response to determining that the actual packet loss rate is greater than the expected random packet loss rate.

16. The apparatus of claim 15, wherein the processor is further configured to compare an actual Layer 4 packet loss rate to an expected Layer 2 packet loss rate.

17. The apparatus of claim 15, wherein the processor is further configured to receive a message reporting the expected random packet loss rate of the network portion.

18. A tangible computer readable medium comprising instructions that when executed by a processor cause the processor to:

send messages to a receiving network device across a network, wherein the network includes a network portion with an expected random packet loss rate;

compare an actual packet loss rate of packets sent across the network to the expected random packet loss rate;

determine that the actual packet loss rate is greater than the expected random packet loss rate; and

compensate for network congestion in response to determining that the actual packet loss rate is greater than the expected random packet loss rate.

19. The computer readable medium of claim 18, wherein the instructions further cause the processor to compare an actual Layer 4 packet loss rate to an expected Layer 2 packet loss rate.

20. The computer readable medium of claim 18, wherein the instructions further cause the processor to receive a message reporting the expected random packet loss rate of the network portion.