Duplicating traffic along local detours before path remerge to increase packet delivery

Patent metadata

Field	Value
Publication number	US-9444727-B2
Application number	US-201213652971-A
Country	US
Kind code	B2
Filing date	Oct 16, 2012
Priority date	Oct 16, 2012
Publication date	Sep 13, 2016
Grant date	Sep 13, 2016

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.

First claim

What is claimed is:

1. A method, comprising:
receiving, at a node, a first copy of a packet with an indication of duplicate copies, the indication inserted in the first copy and at least one second copy when a path to a primary parent of a source node is observed to be weak or down;
storing, at the node, an identifier of the first copy of the packet in response to the indication;
receiving, at the node, a second copy of the packet with the indication of duplicate copies;
determining, at the node, whether the identifier of the second copy matches the stored identifier of the first copy;
in response to a match, dropping, at the node, the second copy;
deleting the stored identifier after expiration of a timer; and
returning, by the node, feedback to a source of the packet regarding an amount of duplicate copy drops.

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:
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.

5. A method, comprising:
monitoring, at a node, a quality of a primary link; and
forwarding, by the node, a plurality of duplicate copies of a packet in response to a poor quality of the primary link, wherein forwarding comprises:
transmitting, by the node, a first copy of the packet on the primary link with an indication of duplicate copies;
transmitting, by the node, 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;
receiving, by the node, feedback from nodes dropping duplicate copies of the packet regarding an amount of duplicate copy drops at the nodes dropping the duplicate copies; and
determining, by the node, a number of N copies to be transmitted based on the feedback from the nodes.

6. The method as in claim 5 , 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.

7. The method as in claim 5 , wherein the backup link is an arbitrary link.

8. The method as in claim 5 , further comprising:
determining a value of N based on a number of acknowledged copies of duplicated packets.

9. 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, the indication inserted in the first copy and at least one second copy when a path to a primary parent of a source node is observed to be weak or down;
store an identifier of the first copy of the packet in response to the indication;
receive the 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;
in response to a match, drop the second copy;
delete the stored identifier after expiration of a timer; and
return feedback to a source of the packet regarding an amount of duplicate copy drops.

10. The apparatus as in claim 9 , wherein the identifier is a hash of the packet.

11. The apparatus as in claim 9 , wherein the identifier is a sequence number of the packet.

12. The apparatus as in claim 9 , 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.

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:
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 to limit duplication of traffic to a limited path segment up to a point where diverse paths remerge;
receive feedback from nodes dropping duplicate copies of the packet regarding an amount of duplicate copy drops at the nodes at the nodes dropping the duplicate copies; and
determine a number of N copies to be transmitted based on the feedback from the nodes dropping the duplicate copies.

14. The apparatus as in claim 13 , 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.

15. The apparatus as in claim 13 , wherein the backup link is an arbitrary link.

16. The apparatus as in claim 13 , wherein the process when executed is further operable to:
determine a value of N based on a number of acknowledged copies of duplicated packets.

Assignees

• Cisco Tech Inc

Inventors

• Vasseur Jean-Philippe
• Hui Jonathan W
• Mahamuni Atul B

Classifications

• H04L41/0668

  by dynamic selection of recovery network elements, e.g. replacement by the most appropriate element after failure · CPC title

• H04L43/0811

  by checking connectivity · CPC title

• H04L45/24 Primary

  Multipath · CPC title