Segment Routing-MPLS Interworking Gateway Stitching RT

[abdullahbinmanzoor]

Hi I am testing srv6 mpls IWG on XRv9K. Issue is it isn't exporting routes from MPLS domain to SRv6 with stitching RT. I have double checked my configs which are fine and even show output is saying ** reoriginated with stitching-rt ** but still not doing it, Interworking itself is working when I add an import for MPLS RT in SRv6 PE. Can anyone shed some light on it, Configs are attached as well as some show commands output.

[abdullahbinmanzoor]

++ Attachements

[Harold Ritter · Accepted solution]

Hi @abdullahbinmanzoor ,

Since you receive the RT:100:1001 from both the SRv6 PE and MPLS PE, you should configure VRF RED as follow on SRv6-PE1.

vrf RED
address-family ipv4 unicast
import route-target
100:1001
100:1001 stitching
!
export route-target
100:1001
100:1001 stitching

Also, make sure that all the PEs have a different route distinguisher (RD), which is best practice in an SP network anyway.

Regards,

Harold

[abdullahbinmanzoor]

Thanks for the advice @Harold Ritter . I've changed RD configs to auto with same 100:1001 MPLS RT and 100:6001 Stitching RT and now its working like a charm. What I don't understand here is why RD has this effect. I had following RD before:
100:1001 on both SRv6-IGW and MPLS PE  and
100:6001 on SRv6 PE.
*** reoriginated with stitching-rt ***
Extended community: RT:100:6001
Source AFI: VPNv4 Unicast, Source VRF: default, Source Route Distinguisher: 1.1.1.11:1

[Harold Ritter]

Hi @abdullahbinmanzoor ,

I have seen issues in the past where using the same RD across the topology would cause a similar issue. I think reconfiguring with a different RD in your lab (auto RD) reinitialized the BGP sessions and might explain why it is now working.

Although it might not have been the cause of the issue in this case, it is still a good practice to use a different RD per PE in an SP topology.

Regards,

Harold

[abdullahbinmanzoor]

Thank you so much for your support.

[Harold Ritter]

You are very welcome @abdullahbinmanzoor and thanks for the feedback