DUPLICATING TRAFFIC ALONG LOCAL DETOURS BEFORE PATH REMERGE TO INCREASE PACKET DELIVERY

• US 20140105033A1
• Filed: 10/16/2012
• Published: 04/17/2014
• Est. Priority Date: 10/16/2012
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Vasseur, Jean-Philippe, Hui, Jonathan W., Mahamuni, Atul B.
• Granted Patent: US 9,444,727 B2
• Time in Patent Office: Days
• US Class Current: 370/248
• CPC Class Codes: H04L 41/0668 by dynamic selection of recovery network elements, e.g. replacement by the most appropriate element after failure
• CPC Class Codes: H04L 43/0811 by checking connectivity
• CPC Class Codes: H04L 45/24 Multipath

Abstract

In one embodiment, a source node monitors a quality of a primary link, and forwards one or more duplicate copies of a packet in response to poor quality of the primary link. Specifically, forwarding generally comprises transmitting a first copy of the packet on the primary link with an indication of duplicate copies, and transmitting a second copy of the packet on a backup link with an indication of duplicate copies. In another embodiment, an intermediate node receives a first copy of a packet with an indication of duplicate copies, and stores an identifier of the first copy of the packet in response to the indication. Upon receiving a second copy of the packet with the indication of duplicate copies, the node determines whether the identifier of the second copy matches the stored identifier of the first copy, such that in response to a match, the second copy is dropped.

Claims

1. A method, comprising:

receiving a first copy of a packet with an indication of duplicate copies;

storing an identifier of the first copy of the packet in response to the indication;

receiving a second copy of the packet with the indication of duplicate copies;

determining whether the identifier of the second copy matches the stored identifier of the first copy; and

in response to a match, dropping the second copy.

2. The method as in claim 1, wherein the identifier is a hash of the packet.

3. The method as in claim 1, wherein the identifier is a sequence number of the packet.

4. The method as in claim 1, further comprising:

deleting the stored identifier after expiration of a timer.

5. The method as in claim 1, further comprising:

returning feedback to a source of the packet regarding an amount of duplicate copy drops.

6. The method as in claim 1, further comprising:

storing the first copy of the packet; and

deciding whether to drop the first or second copy based on a quality of the first or second packet.

7. A method, comprising:

monitoring a quality of a primary link; and

forwarding one or more duplicate copies of a packet in response to a poor quality of the primary link, wherein forwarding comprises;

transmitting a first copy of the packet on the primary link with an indication of duplicate copies; and

transmitting a second copy of the packet on a backup link with an indication of duplicate copies;

wherein the second copy of the packet with the indication of duplicate copies causes nodes receiving the second copy to determine whether the identifier of the second ii copy matches the stored identifier of the first copy, and to drop the second copy in response to a match.

8. The method as in claim 7, further comprising:

including a depth value within duplicate copies of the packet to prevent the duplicate copies from traversing links away from a destination of the packet.

9. The method as in claim 7, wherein the backup link is an arbitrary link.

10. The method as in claim 7, further comprising:

transmitting N copies of the packet.

11. The method as in claim 10, further comprising:

determining a value of N based on a number of acknowledged copies of duplicated packets.

12. The method as in claim 10, further comprising:

determining a value of N based on feedback received from nodes dropping duplicated packets.

13. An apparatus, comprising:

one or more network interfaces to communicate with a computer network;

a processor coupled to the network interfaces and adapted to execute one or more processes; and

a memory configured to store a process executable by the processor, the process when executed operable to;

receive a first copy of a packet with an indication of duplicate copies;

store an identifier of the first copy of the packet in response to the indication;

receive a second copy of the packet with the indication of duplicate copies;

determine whether the identifier of the second copy matches the stored identifier of the first copy; and

in response to a match, drop the second copy.

14. The apparatus as in claim 13, wherein the identifier is a hash of the packet.

15. The apparatus as in claim 13, wherein the identifier is a sequence number of the packet.

16. The apparatus as in claim 13, wherein the process when executed is further operable to:

delete the stored identifier after expiration of a timer.

17. The apparatus as in claim 13, wherein the process when executed is further operable to:

return feedback to a source of the packet regarding an amount of duplicate copy drops.

18. The apparatus as in claim 13, wherein the process when executed is further operable to:

store the first copy of the packet; and

decide whether to drop the first or second copy based on a quality of the first or second packet.

19. An apparatus, comprising:

one or more network interfaces to communicate with a computer network;

a processor coupled to the network interfaces and adapted to execute one or more processes; and

a memory configured to store a process executable by the processor, the process when executed operable to;

monitor a quality of a primary link; and

forward one or more duplicate copies of a packet in response to a poor quality of the primary link, wherein the process is configured to forward by;

transmitting a first copy of the packet on the primary link with an indication of duplicate copies; and

transmitting a second copy of the packet on a backup link with an indication of duplicate copies;

wherein the second copy of the packet with the indication of duplicate copies causes nodes receiving the second copy to determine whether the identifier of the second copy matches the stored identifier of the first copy, and to drop the second copy in response to a match.

20. The apparatus as in claim 19, wherein the process when executed is further operable to:

include a depth value within duplicate copies of the packet to prevent the duplicate copies from traversing links away from a destination of the packet.

21. The apparatus as in claim 19, wherein the backup link is an arbitrary link.

22. The apparatus as in claim 19, wherein the process when executed is further operable to:

transmit N copies of the packet.

23. The apparatus as in claim 22, wherein the process when executed is further operable to:

determine a value of N based on a number of acknowledged copies of duplicated packets.

24. The apparatus as in claim 22, wherein the process when executed is further operable to:

determine a value of N based on feedback received from nodes dropping duplicated packets.