METHOD, SYSTEM, AND APPARATUS FOR ACCELERATING RESOLUTION OF NETWORK CONGESTION

• US 20090086637A1
• Filed: 09/27/2007
• Published: 04/02/2009
• Est. Priority Date: 09/27/2007
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: DeCusatis, Casimer, Gregg, Thomas A.
• Granted Patent: US 7,839,777 B2
• Time in Patent Office: Days
• US Class Current: 370/236.100
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/11 Identifying congestion
• CPC Class Codes: H04L 47/263 Rate modification at the source after receiving feedback

Abstract

The response time for resolving network traffic congestion is accelerated in a Data Center Ethernet (DCE) network. A data packet is received at a node in the network. Congestion of the data packet at the node is detected, and a backward congestion notification signal for the data packet is generated. A packet injection rate is adapted based on at least one of the backward congestion notification signal generated by the node and another backward congestion notification signal.

Claims

1. A method for managing backward congestion in a Data Center Ethernet (DCE) network, comprising:

receiving a data packet at a node in the network;

detecting congestion of the data packet at the node in the network;

generating at least one backward congestion notification signal for the data packet at the node in the network, wherein a packet injection rate is adapted based on at least one of the backward congestion notification signal generated by the node in the network and another backward congestion notification signal.

2. The method of claim 1, wherein the data packet is received at the node in the network from a source node, the other backward congestion notification signal is generated by a destination node and transmitted for the data packet to the source node in response to receipt of a congestion notification signal transmitted with the data packet from the node in the network, and the source node adapts the packet injection rate based on the backward congestion signal received first.

3. The method of claim 2, wherein the congestion notification signal is a data bit included in a data packet header of the data packet transmitted to the destination node, and each backward congestion notification signal is a data bit included in a data packet header transmitted to the source node.

4. The method of claim 3, wherein each data packet header including a backward congestion notification signal also includes a field indicating a source of the backward congestion notification signal.

5. The method of claim 2, wherein each data packet header includes a packet sequence number (PSN) for that data packet.

6. The method of claim 5, wherein if one or more backward congestion notification signals are received for the same data packet, duplication of the backward congestion notification signal is detected by comparison of the PSNs included in the data headers with the backward congestion notification signals.

7. The method of claim 6, further comprising ignoring a duplicate backward congestion notification signal received subsequently for the data packet.

8. A system for managing backward network congestion in a Data Center Ethernet (DCE) network, comprising:

a source node for transmitting data packets;

a destination node for receiving the data packets; and

at least one node interspersed between the source node and the destination node for receiving a data packet from the source node, detecting congestion of the data packet in the network, generating a congestion notification signal indicating congestion of the data packet, and transmitting the data picket with the congestion notification signal to a destination node in the network;

wherein the node generates a backward congestion notification signal and transmits the backward congestion notification signal to the source node;

the destination node receives the congestion notification signal, generates a backward congestion notification signal and transmits the backward congestion notification signal to the source node; and

the source node receives at least one of the backward congestion notification signals and adapts a packet injection rate based on the backward congestion notification signal received first.

9. The system of claim 8, wherein the congestion notification signal is a data bit included in a data packet header of the data packet transmitted to the destination node.

10. The system of claim 8, wherein each backward congestion notification signal is a data bit included in a data packet header transmitted to the source node.

11. The system of claim 10, wherein the data packet header including the backward congestion notification signal also includes a field indicating a source of the backward congestion notification signal.

12. The system of claim 8, wherein each data packet header includes a packet sequence number (PSN) for that data packet.

13. The system of claim 12, wherein if the source node subsequently receives one or more backward congestion notification signals for the same data packet, the source node detects duplication of the backward congestion notification signal by comparison of the PSNs included in the data headers with the backward congestion notification signals.

14. The system claim 13, wherein the source node ignores a duplicate backward congestion notification signal received subsequently for the data packet at the source node.

15. An apparatus for managing backward network congestion in a Data Center Ethernet (DCE) network, comprising:

an input for receiving a data packet;

a detector for detecting congestion of the data packet; and

a packet generator for generating a backward congestion notification signal for the data packet, wherein a packet injection rate is adapted based on at least one of the backward congestion notification signal generated by the packet generator and another backward congestion notification signal.

16. The apparatus of claim 15, the apparatus further comprising:

an output for transmitting a congestion notification signal with the data packet to a destination node; and

another output for transmitting the backward congestion notification signal for the data packet to a source node, wherein the other backward congestion notification signal is generated by the destination node and transmitted for the data packet to the source node in response to receipt of the congestion notification signal, and the source node adapts the packet injection rate based on the backward congestion notification signal received first.

17. The apparatus of claim 16, wherein the congestion notification signal is a data bit included in a header of the data packet transmitted to the destination node, and each backward congestion notification signal is a data bit included in a header of a data packet transmitted to the source node.

18. The apparatus of claim 17, wherein each data packet header including a backward congestion notification signal also includes a field indicating a source of the backward congestion notification signal.

19. The apparatus of claim 16, wherein each data packet header includes a packet sequence number (PSN) for that data packet.

20. The apparatus of claim 19, wherein if one or more backward notification signals are received for the same data packet, duplication of the backward notification signal is detected by comparison of the PSNs included in the data headers with the backward congestion notification signals, and a duplicate backward congestion notification signal received subsequently for the data packet is ignored.