Seamless MPLS in Nokia (Alcatel-Lucent) SR OS and Cisco IOS XR

Anton Karneliuk. IT & Network Expert / Architect / Manager; Project Manager; Entrepreneur; 2x CCIE (RS/SP) #49412; MSc Telecommunications.

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  1. Hi sir Anton. Thank you for your article really helped me in understanding Seamless MPLS. I am a final semester students who are taking final task about seamless mpls. What if I want to replace ISIS with OSPF? Would you please tell me the configuration? I would be very grateful if you would reply to my question. Thank you once again sir 🙂

    1. Hi Nisa,
      thanks for your question. Actually the configuration will be just the same. I’d configure ACCESS network as any non-backbone stub area (i.e. area 0.0.0.1 stub) and CORE network as backbone. you should filter at SR2 routes so that only it’s loopback besides default route is injected into area 0.0.0.1. Everything other doesn’t differ.
      BR,
      Anton

      1. Thanks sir for the answer. But sir I have an issue when trying to make policy-statement RP_NO_ISIS_LEAK with ospf.
        1. I cant do “action drop” in my configuration, theres only “action accept” and “reject”, is “action reject” and “action drop” has similar purpose?
        2. In IS-IS you use policy-statement RP_NO_ISIS_LEAK>>entry 10>>from>>level 1>>to>>level 2, what should it be in ospf? Because I cant use from>>area 0.0.0.1>>to>>area 0.0.0.0, I cant assign area 0.0.0.0 as destination prefix, theres only neighbor and prefix-list.
        Your answer would be really helpful for me sir.

        1. Hi Nisa,

          You can’t apply ISIS policies for OSPF.
          1) “reject” and “drop” are similar actions.
          2) ISIS don’t have that area in the same meaning as OSPF. ISIS has concept of level instead.

          BR,
          Anton

  2. Hi Sir Anton, Thank you for your article really helped me in understanding Seamless MPLS. I am working on VPLS related stuff. It would be good if you can post some article on VPLS in Seamless MPLS Networks and also protection mechanism for VPLS in Seamless MPLS Networks.

    1. Hi Srikanth,
      In general VPLS might work in the seamless MPLS scenario in the much same way as in ordinary scenario, if inter-AS option C is deployed. You need to take care about inter-AS MPLS LSP, which is not related to VPLS.
      If you deploy Option-B, then you will have stiching at ASBR. This scenario is much more complex.
      BR,
      Anton

      1. Hi Sir Anton, Thanks for your reply. I would like to understand how load balancing works for VPLS in seamless MPLS Networks from forwarding plane perspective . It would be good if you can post some article related to this.

        1. Hi Srikanth,

          It fully depends on your configuration. And VPLS or VPWS it doesn’t play major role to be honest. What matters, how you provision e2e path. If you have multipe ABR/ASBR routers and therfore multiple options how to reach PE in another part of the network AND you use LDP or SR, then you have possibility for load balancing within VPLS. Don’t forget to enable control-world and entropy label if it’s supported. If you use MPLS-TE with RSVP or SR-TE, typically you won’t have load balancing within your VPLS.

          Hope this helps.

          BR,
          Anton

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