Shortening of service paths in service chains in a communications network

Patent metadata

Field	Value
Publication number	US-9559970-B2
Application number	US-201615055691-A
Country	US
Kind code	B2
Filing date	Feb 29, 2016
Priority date	Nov 15, 2013
Publication date	Jan 31, 2017
Grant date	Jan 31, 2017

Abstract

A method is provided in one embodiment and includes receiving at a network element a flow offload decision for a first service node that includes a portion of a service chain for processing a flow; recording the flow offload decision against the first service node at the network element; and propagating the flow offload decision backward on a service path to which the flow belongs if the first service node is hosted at the network element. Embodiments may also include propagating the flow offload decision backward on a service path to which the flow belongs if the flow offload decision is a propagated flow offload decision and the network element hosts a second service node that immediately precedes the service node on behalf of which the propagated flow offload decision was received and a flow offload decision has already been received by the network element from the second service node.

First claim

What is claimed is:

1. A method comprising:
receiving at a network element a flow offload decision for a first service node comprising a portion of a service chain for processing a flow; and
propagating the flow offload decision backward on a service path to which the flow belongs when:
the flow offload decision is a propagated flow offload decision;
the network element hosts a second service node that immediately precedes the first service node; and
the flow offload decision has already been received by the network element for the second service node.

2. The method of claim 1 further comprising:
recording the flow offload decision against the first service node at the network element; and
propagating the flow offload decision backward on the service path to which the flow belongs when the first service node is hosted at the network element.

3. The method of claim 1 further comprising recording the flow offload decision against the first service node at each additional network element to which the flow offload decision is propagated.

4. The method of claim 1 , wherein the network element comprises a Virtual Ethernet Module (“VEM”) including a distributed virtual switch (“DVS”).

5. The method of claim 1 further comprising providing at the network element a service forwarding table associated with the flow, the service forwarding table including an entry corresponding to each service node of the service chain hosted by the network element, wherein each entry indicates a next hop and a previous hop for the corresponding service node of the service chain.

6. The method of claim 5 , wherein the propagating comprises propagating the flow offload decision to the previous hop indicated in the service forwarding table entry corresponding to the first service node.

7. The method of claim 5 , wherein the recording comprises indicating in the service forwarding table that the first service node has been offloaded for the flow.

8. The method of claim 7 further comprising forwarding a packet of the flow received at the network element to a next hop service node as indicated by the service forwarding table, wherein if when a corresponding service table entry indicates that the next hop service node has been offloaded, the packet is forwarded to a first next hop service node in the service chain that has not been offloaded.

9. One or more non-transitory tangible media that includes code for execution and when executed by a processor is operable to perform operations, comprising:
receiving at a network element a flow offload decision for a first service node comprising a portion of a service chain for processing a flow; and
propagating the flow offload decision backward on a service path to which the flow belongs when:
the flow offload decision is a propagated flow offload decision;
the network element hosts a second service node that immediately precedes the first service node; and
the flow offload decision has already been received by the network element for the second service node.

10. The media of claim 9 wherein the operations further comprise:
recording the flow offload decision against the first service node at the network element; and
propagating the flow offload decision backward on the service path to which the flow belongs when the first service node is hosted at the network element.

11. The one or more non-transitory tangible media of claim 9 further including code for execution and when executed by the processor is operable to perform operations comprising recording the flow offload decision against the first service node at each additional network element to which the flow offload decision is propagated.

12. The one or more non-transitory tangible media of claim 9 further including code for execution and when executed by the processor is operable to perform operations comprising providing at the network element a service forwarding table associated with the flow, the service forwarding table including an entry corresponding to each service node of the service chain hosted by the network element, wherein each entry indicates a next hop and a previous hop for the corresponding service node of the service chain.

13. The one or more non-transitory tangible media of claim 12 , wherein the propagating comprises propagating the flow offload decision to the previous hop indicated in the service forwarding table entry corresponding to the first service node.

14. The one or more non-transitory tangible media of claim 12 , wherein the recording comprises indicating in the service forwarding table that the first service node has been offloaded for the flow.

15. The one or more non-transitory tangible media of claim 14 further including code for execution and when executed by the processor is operable to perform operations comprising forwarding a packet of the flow received at the network element to a next hop service node as indicated by the service forwarding table, wherein when a corresponding service table entry indicates that the next hop service node has been offloaded, the packet is forwarded to a first next hop service node in the service chain that has not been offloaded.

16. An apparatus, comprising:
a memory element configured to store data;
a processor operable to execute instructions associated with the data; and a service path shortening module configured to:
receive at a network element a flow offload decision for a first service node comprising a portion of a service chain for processing a flow; and
propagate the flow offload decision backward on a service path to which the flow belongs when:
the flow offload decision is a propagated flow offload decision;
the network element hosts a second service node that immediately precedes the first service node; and
the flow offload decision has already been received by the network element for the second service node.

17. The apparatus of claim 16 , wherein the service path shortening module is further configured to:
record the flow offload decision against the first service node at the network element; and
propagate the flow offload decision backward on the service path to which the flow belongs when the first service node is hosted at the network element.

18. The apparatus of claim 16 , wherein the service path shortening module is further configured to provide at the network element a service forwarding table associated with the flow, the service forwarding table including an entry corresponding to each service node of the service chain hosted by the network element, wherein each entry indicates a next hop and a previous hop for the corresponding service node of the service chain.

19. The apparatus of claim 18 , wherein the propagating comprises propagating the flow offload decision to the previous hop indicated in the service forwarding table entry corresponding to the first service node and wherein the recording comprises indicating in the service forwarding table that the first service node has been offloaded for the flow.

20. The apparatus of claim 18 , wherein the service path shortening module is further configured to forward a packet of the flow received at the network element to a next hop service node as indicated by the service forwarding table, wherein when a corresponding service table entry indicates that the next hop service node has been offloaded, the packet is forwarded to a first next hop service node in the service chain that has not been offloaded.

Assignees

• Cisco Tech Inc

Inventors

• Kumar Surendra M
• Bagepalli Nagaraj A
• Devireddy Dileep K
• Patra Abhijit

Classifications

• H04L47/2475 Primary

  for supporting traffic characterised by the type of applications · CPC title

• H04L45/38 Primary

  Flow based routing · CPC title

• H04L47/12

  Avoiding congestion; Recovering from congestion · CPC title

• H04L45/12

  Shortest path evaluation · CPC title

• H04L43/026

  using flow identification · CPC title