Granted Patent B2

US 12,744,733 · App. 18/776,125 · Granted Sep 22, 2026

Inventors: Todd Defilippi (Redwood City, CA); Amal Karboubi (Ottawa, CA)

Assignee: Ciena Corporation

H04L45/74H04L45/02

Abstract

Claims (44)

1 . A non-transitory computer-readable medium storing instructions that, when executed, cause one or more processors to execute steps of:

performing a path calculation to determine a calculated path in a Segment Routing network without considering any domain border routers, wherein the Segment Routing network includes a plurality of domains with the calculated path being through at least two domains;

obtaining a compressed segment list for the calculated path, wherein the compressed segment list includes a plurality of Segment Identifiers (SID) each SID identifying a segment, and wherein, when expanded, the compressed segment list matches the calculated path;

analyzing the compressed segment list for any domain border routers between two domains of the at least two domains to determine associated anycast SID for the any domain border routers, wherein the analyzing includes (i) identifying, from the calculated path, a domain border router between a first domain and a second domain and identifying one or more corresponding domain border routers that participate in both the first domain and the second domain, and (ii) monitoring advertisements in the Segment Routing network to determine an anycast prefix and a corresponding anycast SID that are advertised by exactly the corresponding domain border routers; and

utilizing the associated anycast SID in the compressed SID list for resiliency between the two domains, wherein utilizing includes replacing a node SID for the domain border router in the compressed segment list with the anycast SID.

2 . The non-transitory computer-readable medium of claim 1 , wherein the analyzing further includes steps of

identifying a domain border router between the two domains; and

for the identified domain border router, identifying corresponding one or more domain border routers and determining the associated anycast SID based thereon.

3 . The non-transitory computer-readable medium of claim 2 , wherein the analyzing the compressed segment list includes identifying the domain border router based on a corresponding node SID in the plurality of SIDs.

4 . The non-transitory computer-readable medium of claim 1 , wherein the plurality of Segment Identifiers (SID) include node SIDs.

5 . The non-transitory computer-readable medium of claim 1 , wherein the plurality of Segment Identifiers (SID) include node SIDs and adjacency SIDs.

6 . The non-transitory computer-readable medium of claim 1 , wherein the steps further include

prior to the obtaining and subsequent to the performing, determining the compressed segment list with node SIDs and with zero or more adjacency SIDs.

7 . The non-transitory computer-readable medium of claim 1 , wherein the steps further include

monitoring advertisements from the Segment Routing network to determine the domain border routers and the associated anycast SIDs.

8 . A method comprising steps of:

performing a path calculation to determine a calculated path in a Segment Routing network without considering any domain border routers, wherein the Segment Routing network includes a plurality of domains with the calculated path being through at least two domains;

obtaining a compressed segment list for the calculated path, wherein the compressed segment list includes a plurality of Segment Identifiers (SID) each SID identifying a segment, and wherein, when expanded, the compressed segment list matches the calculated path;

analyzing the compressed segment list for any domain border routers between two domains of the at least two domains to determine associated anycast SID for the any domain border routers, wherein the analyzing includes (i) identifying, from the calculated path, a domain border router between a first domain and a second domain and identifying one or more corresponding domain border routers that participate in both the first domain and the second domain, and (ii) monitoring advertisements in the Segment Routing network to determine an anycast prefix and a corresponding anycast SID that are advertised by exactly the corresponding domain border routers; and

utilizing the associated anycast SID in the compressed SID list for resiliency between the two domains, wherein utilizing includes replacing a node SID for the domain border router in the compressed segment list with the anycast SID.

9 . The method of claim 8 , wherein the analyzing further includes steps of

identifying a domain border router between the two domains; and

for the identified domain border router, identifying corresponding one or more domain border routers and determining the associated anycast SID based thereon.

10 . The method of claim 9 , wherein the analyzing the compressed segment list includes identifying the domain border router based on a corresponding node SID in the plurality of SIDs.

11 . The method of claim 8 , wherein the plurality of Segment Identifiers (SID) include node SIDs.

12 . The method of claim 8 , wherein the plurality of Segment Identifiers (SID) include node SIDs and adjacency SIDs.

13 . The method of claim 8 , wherein the steps further include

prior to the obtaining and subsequent to the performing, determining the compressed segment list with node SIDs and with zero or more adjacency SIDs.

14 . The method of claim 8 , wherein the steps further include

monitoring advertisements from the Segment Routing network to determine the domain border routers and the associated anycast SIDs.

15 . An apparatus comprising:

one or more processors;

a network interface communicatively coupled to a Segment Routing network; and

memory storing instructions that, when executed, cause the one or more processors to

perform a path calculation to determine a calculated path in a Segment Routing network without considering any domain border routers, wherein the Segment Routing network includes a plurality of domains with the calculated path being through at least two domains,

obtain a compressed segment list for the calculated path, wherein the compressed segment list includes a plurality of Segment Identifiers (SID) each SID identifying a segment, and wherein, when expanded, the compressed segment list matches the calculated path,

analyze the compressed segment list for any domain border routers between two domains of the at least two domains to determine associated anycast SID for the any domain border routers, wherein the analyzing includes (i) identifying, from the calculated path, a domain border router between a first domain and a second domain and identifying one or more corresponding domain border routers that participate in both the first domain and the second domain, and (ii) monitoring advertisements in the Segment Routing network to determine an anycast prefix and a corresponding anycast SID that are advertised by exactly the corresponding domain border routers, and

utilize the associated anycast SID in the compressed SID list for resiliency between the two domains, wherein utilizing includes replacing a node SID for the domain border router in the compressed segment list with the anycast SID.

16 . The apparatus of claim 15 , wherein the compressed segment list is analyzed by

identify a domain border router between the two domains, and

for the identified domain border router, identify corresponding one or more domain border routers and determining the associated anycast SID based thereon.

17 . The apparatus of claim 15 , wherein the plurality of Segment Identifiers (SID) include node SIDs.

18 . The apparatus of claim 15 , wherein the memory storing instructions that, when executed, further cause the one or more processors to

monitor advertisements from the Segment Routing network to determine the domain border routers and the associated anycast SIDs.

Assignments (1)

Continuity (1)

References Cited (57)