Using border gateway protocol to expose maximum segment identifier depth to an external application

Patent metadata

Field	Value
Publication number	US-9967184-B2
Application number	US-201514846342-A
Country	US
Kind code	B2
Filing date	Sep 4, 2015
Priority date	Jul 2, 2015
Publication date	May 8, 2018
Grant date	May 8, 2018

Abstract

A method implemented by a network device acting as a border gateway protocol (BGP) speaker, of exposing a maximum segment identifier depth (MSD) value of the network device is described. The method comprises encoding the MSD value into a BGP Link State (BGP-LS) extension message. The BGP-LS extension message includes a type, a length and a MSD value. The type indicates the type of the MSD value, the length indicates the length of the MSD value and the MSD value indicates a lowest MSD value supported by the network device for enabling segment routing. The method continues with transmitting the BGP-LS extension message including the type, the length, and the MSD value to a network controller, where the network controller is to use the MSD value to compute a segment routing path including the network device.

First claim

What is claimed is:

1. A method implemented by a network device acting as a border gateway protocol (BGP) speaker, of exposing a maximum segment identifier depth (MSD) value of the network device, the method comprising:
encoding the MSD value into a BGP Link State (BGP-LS) extension message, wherein the BGP-LS extension message includes a type, a length and a MSD value, and wherein the type indicates the type of the MSD value, the length indicates the length of the MSD value and the MSD value is a number that is a maximum number of segment routing (SR) labels supported by the network device, wherein an SR label includes instructions for steering a packet through an SR network and each one of the SR labels is included in an SR header which is to be prepended onto a packet at ingress of the SR network; and
transmitting the BGP-LS extension message including the type, the length, and the MSD value to a network controller, wherein the network controller is to use the MSD value to compute a segment routing path including the network device, wherein the label stack depth of the segment routing path does not exceed the MSD value supported by the network device.

2. The method of claim 1 , wherein the MSD value is a node MSD value indicative of a lowest MSD value supported by the network device.

3. The method of claim 1 , wherein the MSD value is a link MSD value indicative of a lowest MSD value supported by a link of the network device.

4. The method of claim 1 , wherein the network device is an ingress node of the segment routing path.

5. A network device acting as a border gateway protocol (BGP) speaker, the network device to be coupled to a network controller, comprising:
a processor and a memory, said memory containing instructions executable by the processor whereby the network device is operative to:
encode a maximum segment identifier depth (MSD) value of the network device into a BGP Link State (BGP-LS) extension message, wherein the BGP-LS extension message includes a type, a length and an MSD value, and wherein the type indicates the type of the MSD value, the length indicates the length of the MSD value and the MSD value is a number that is a maximum number of segment routing (SR) labels supported by the network device, wherein an SR label includes instructions for steering a packet through an SR network and each one of the SR labels is included in an SR header which is to be prepended onto a packet at ingress of the SR network; and
transmit the BGP-LS extension message including the type, the length, and the MSD value to the network controller, wherein the network controller is to use the MSD value to compute a segment routing path including the network device, wherein the label stack depth of the segment routing path does not exceed the MSD value supported by the network device.

6. The network device of claim 5 , wherein the MSD value is a node MSD value indicative of a lowest MSD value supported by the network device.

7. The network device of claim 5 , wherein the MSD value is a link MSD value indicative of a lowest MSD value supported by a link of the network device.

8. The network device of claim 5 , wherein the network device is an ingress node of the segment routing path.

9. A non-transitory machine-readable storage medium that provides instructions that, if executed by a processor of a network device acting as a border gateway protocol (BGP) speaker and coupled with a network controller, will cause said processor to perform operations comprising:
encoding a maximum segment identifier depth (MSD) value of the network device into a BGP Link State (BGP-LS) extension message, wherein the BGP-LS extension message includes a type, a length and a MSD value, and wherein the type indicates the type of the MSD value, the length indicates the length of the MSD value and the MSD value is a number that is a maximum number of segment routing (SR) labels supported by the network device, wherein an SR label includes instructions for steering a packet through an SR network and each one of the SR labels is included in an SR header which is to be prepended onto a packet at ingress of the SR network; and
transmitting the BGP-LS extension message including the type, the length, and the MSD value to the network controller, wherein the network controller is to use the MSD value to compute a segment routing path including the network device, wherein the label stack depth of the segment routing path does not exceed the MSD value supported by the network device.

10. The non-transitory machine-readable storage medium of claim 9 , wherein the MSD value is a node MSD value indicative of a lowest MSD value supported by the network device.

11. The non-transitory machine-readable storage medium of claim 9 , wherein the MSD value is a link MSD value indicative of a lowest MSD value supported by a link of the network device.

12. The non-transitory machine-readable storage medium of claim 9 , wherein the network device is an ingress node of the segment routing path.

13. A method in a network controller, the method comprising:
receiving from a network device acting as a border gateway protocol (BGP) speaker, a BGP Link State (BGP-LS) extension message;
decoding the BGP-LS extension message, to extract a maximum segment identifier depth (MSD) value of the network device, wherein the BGP-LS extension message includes a type which indicates the type of the MSD value, a length which indicates the length of the MSD value and the MSD value is a number that is a maximum number of segment routing (SR) labels supported by the network device, wherein an SR label includes instructions for steering a packet through an SR network and each one of the SR labels is included in an SR header which is to be prepended onto a packet at ingress of the SR network; and
computing, using the MSD value, a segment routing (SR) path including the network device, wherein the SR path has a label stack depth that is lower than or equal to the MSD value.

14. The method of claim 13 , wherein the type indicates that the MSD value is a node MSD value indicative of a lowest MSD value supported by the network device.

15. The method of claim 13 , wherein the type indicates that the MSD value is a link MSD value indicative of a lowest MSD value supported by a link of the network device.

16. A network controller comprising:
a processor and a memory, said memory containing instructions executable by the processor whereby the network controller is operative to:
receive from a network device acting as a border gateway protocol (BGP) speaker, a BGP Link State (BGP-LS) extension message;
decode the BGP-LS extension message, to extract a maximum segment identifier depth (MSD) value of the network device, wherein the BGP-LS extension message includes a type which indicates the type of the MSD value, a length which indicates the length of the MSD value and the MSD value is a number that is a maximum number of segment routing (SR) labels supported by the network device, wherein an SR label includes instructions for steering a packet through an SR network and each one of the SR labels is included in an SR header which is to be prepended onto a packet at ingress of the SR network; and
compute, using the MSD value, a segment routing (SR) path including the network device, wherein the SR path has a label stack depth that is lower than or equal to the MSD value.

17. The network controller of claim 16 , wherein the type indicates that the MSD value is a node MSD value indicative of a lowest MSD value supported by the network device.

1

Assignees

• Ericsson Telefon Ab L M
• Ericsson Telefon Ab L M

Inventors

• Tantsura Evgeny
• Mirsky Gregory

Classifications

• H04L45/72 Primary

  Routing based on the source address · CPC title

• H04L45/507

  Label distribution · CPC title

• H04L45/02

  Topology update or discovery · CPC title