Resilient segment routing service hunting with TCP session stickiness

Patent metadata

Field	Value
Publication number	US-11277341-B2
Application number	US-201916673508-A
Country	US
Kind code	B2
Filing date	Nov 4, 2019
Priority date	Jul 22, 2015
Publication date	Mar 15, 2022
Grant date	Mar 15, 2022

Abstract

According to one aspect, a method includes obtaining a segment routing (SR) packet from an endpoint via a first router at a first server along a path, the SR packet including an SR list and a last address, the last address being an address of a requested service. The method also includes determining, at the first server, whether the requested service is available from the first server, wherein determining whether the requested service is available from the first server includes opening the SR packet, parsing an SR header of the SR packet, and performing a lookup in a service table. Finally, the method includes modifying the SR packet at the first server when it is determined that the requested service is not available from the first server; and forwarding the SR packet along the path.

First claim

What is claimed is:

1. An apparatus comprising:
a processor;
an input/output (I/O) interface, the I/O interface being configured to obtain a SYN packet, wherein the SYN packet identifies a requested service and includes a source set to identify an endpoint, a destination set to identify a server, and a segment routing (SR) list; and
a logic arrangement, the logic arrangement including program code for execution by the processor and a routing logic module configured to support SR and service hunting, wherein the routing logic module is configured to support the service hunting by verifying whether the requested service is available from the apparatus, wherein the apparatus provides the requested service to the endpoint if it is verified that the requested service is available and the routing logic module routes the SYN packet to a first destination identified in the SR list and sends the SYN packet towards the first destination if it is verified that the requested service is not available from the apparatus.

2. The apparatus of claim 1 , wherein the first destination is an entry in the SR list and also a last address in a SR header associated with the SYN packet.

3. The apparatus of claim 1 , further including a data storage arrangement, the data storage arrangement including a lookup table, wherein the routing logic module is configured to support the service hunting by determining whether the requested service is included in the lookup table.

4. The apparatus of claim 3 , wherein when it is determined that the requested service is not included in the lookup table, the requested service is verified as not available from the apparatus.

5. The apparatus of claim 1 , wherein the routing logic module modifies the SYN packet prior to routing the SYN packet to the first destination.

6. The apparatus of claim 5 , wherein the routing logic module modifies the SYN packet by modifying a destination in the SYN packet to specify the first destination.

7. The apparatus of claim 1 , wherein the SR list identifies a plurality of waypoints along a path that includes an endpoint, the apparatus, and the first destination, and wherein the I/O interface obtains the SYN packet from the endpoint.

8. The apparatus of claim 7 , wherein the apparatus is located along the path between the endpoint and the first destination.

9. The apparatus of claim 1 , wherein a first entry in the SR list identifies the requested service.

10. The apparatus of claim 1 , wherein, when the apparatus provides the requested service to the endpoint, the apparatus facilitates establishing a transmission control protocol (TCP) session between the endpoint and the apparatus.

11. A method comprising:
obtaining, at an apparatus configured to support segment routing and service hunting, a SYN packet, wherein the SYN packet identifies a requested service and includes a source set to identify an endpoint, a destination set to identify a server, and a segment routing (SR) list;
verifying whether the requested service is available from the apparatus;
providing the requested service to the endpoint if it is verified that the requested service is available; and
routing the SYN packet to a first destination identified in the SR list and sending the SYN packet towards the first destination if it is verified that the requested service is not available from the apparatus.

12. The method of claim 11 , wherein the first destination is an entry in the SR list and also a last address in a SR header associated with the SYN packet.

13. The method of claim 11 , wherein the apparatus includes a data storage arrangement including a lookup table, and wherein verifying whether the requested service is available from the apparatus comprises:
determining whether the requested service is included in the lookup table.

14. The method of claim 13 , wherein when it is determined that the requested service is not included in the lookup table, the requested service is verified as not available from the apparatus.

15. The method of claim 11 , further comprising:
modifying the SYN packet prior to routing the SYN packet to the first destination.

16. The method of claim 15 , wherein modifying the SYN packet includes modifying a destination in the SYN packet to specify the first destination.

17. The method of claim 11 , wherein the SR list identifies a plurality of waypoints along a path that includes an endpoint, the apparatus, and the first destination.

18. The method of claim 17 , wherein the apparatus is located along the path between the endpoint and the first destination.

19. The method of claim 11 , wherein a first entry in the SR list identifies the requested service.

20. The method of claim 11 , wherein providing the requested service to the endpoint includes facilitating establishing a transmission control protocol (TCP) session between the endpoint and the apparatus.

Assignees

• Cisco Tech Inc

Inventors

• Townsley William Mark
• Surcouf Andre

Classifications

• H04L45/745 Primary

  Address table lookup; Address filtering · CPC title

• H04L65/612

  for unicast · CPC title

• H04L45/34

  Source routing · CPC title

• H04L45/64

  using an overlay routing layer · CPC title

• H04L45/50

  using label swapping, e.g. multi-protocol label switch [MPLS] · CPC title