ISIS + Segement routing

[Landry Hermann SAMBA]

Hello

I worked for a carrier network ethernet, we have more than 80 nodes (Cisco NCS 5500 and ASR 920), all these nodes run ISIS/LDP/MPLS in order to deliver MEF services like E-LINE, E-ACCESS.

I heard about segment-routing, I have setup a lab in order to see if I can continu to provide same services (E-LINE, E-ACCESS) if I implement segment routing.

I do lab and I remark even if LDP configuration was removed and segment-routing active, when I configure E-LINE service, LDP session still active between end-to-end node.

I dont  understand why LDP still active while segment routing is live.

if some one knows I'll be glad to exchange, and I can provide more information.

Thank you.

[Harold Ritter · Accepted solution]

Hi @Landry Hermann SAMBA ,

L2VPN services use LDP between PEs to exchange labels. This is a targeted LDP session between the PEs and will work whether you use LDP or SR in your core.

Regards,

[Landry Hermann SAMBA]

Hello @Harold Ritter 

Thank you for your reply.

AS LDP session will be setup anyway between PEs for L2VNP services, Please, what can you see any benefits for me to migration my core network to segment-routing ?

I have an other issue refer at this link https://community.cisco.com/t5/routing/isis-metric-delay/m-p/4594296#M365317 any idea will be wellcome.

Thank you again.

[Harold Ritter]

Hi @Landry Hermann SAMBA ,

I believe using Segment Routing (SR) in the core could still bring benefits (other than completely eliminating LDP in your network). SR offers much more flexibility for traffic engineering and is easier to troubleshoot given it global label. This is a personal preference. You need to see if the migration is worth it for you ion your network.

Regards,