SPv3 Inter-AS mVPN IOS-XR

Guys,

How to check PIM Vector information in XR? I have enabled it as follows-

router pim

address-family ipv4

rpf-vector

!

 

Regards,

AB.

Comments

  • In IOS I know you do this:

    R3#sh run | s multicast

    ip multicast-routing 

    ip multicast rpf proxy vector

     

    You activate it by using MDT address family

     

    R3#sh ip mroute 

    IP Multicast Routing Table

    (19.19.19.19, 232.0.0.1), 08:12:05/00:03:18, flags: sTv

      Incoming interface: Ethernet1/5, RPF nbr 10.11.34.4, vector 4.4.4.4

      Outgoing interface list:

        Ethernet1/0, Forward/Sparse, 08:12:05/00:03:18

     

     

    R3#sh ip rpf 19.19.19.19

     failed, no route exists

     

     

    Maybe all you have to do is activate MDT AFI/SAFI in IOS-XR?

  • Maybe all you have to do is activate MDT AFI/SAFI in IOS-XR?

    Yep done that and PIM SSM enabled. The NLRI is imported into VRF (IOS-XR caveat: RD must match between PEs) but no Join-Prune messages sent out.

    Cheers,

    AB.

  • Yep done that and PIM SSM enabled. The NLRI is imported into VRF (IOS-XR caveat: RD must match between PEs) but no Join-Prune messages sent out.

    What is the next hop of the NLRIs that you are imporing? Does the local device have an RPF entry for this? If not, try changing the NH of the received NLRIs to that of the ASBR's address. 

     

  • I have set next-hop-self on ASBRs when advertising remote MDT NLRIs within the local AS. So that's all good I think.

    Cheers,

    AB.

  • How to check PIM Vector information in XR? I have enabled it as follows-

    router pim

    address-family ipv4

    rpf-vector

    !

     

    What about enableing this under the VRF that you are importing the NLRIs into?  This config would be good for P routers, but I think that the PE needs this in the VRF specific PIM process?

     

  • Not only is this silly, it's actually not-efficient.

    This is my Inter-AS Option-B topology - R3(PE), R2(P) and R4(ASBR) are in AS100. R6(ASBR) and R8(PE) in AS200.

    R3---R2---R4---R6---R8

    RPF-Vector is not assigned dynamically; I had to manually assign the PIM Vector. The configuration that worked for me on R3 is-

    router pim

     address-family ipv4

      rpf-vector inject 8.8.8.8 masklen 32 4.4.4.4

      rpf-vector

     !

     vrf Inter-AS1

      address-family ipv4

       rpf-vector

      !

     !


    If I had another ASBR (say R5) in AS100 and if R4-R6 link goes down, I lose all Inter-AS mVPN traffic.


    Obviously, if you dont want to get into this mess of PIM Vector, just redistribute PE addresses into IGP in the local domain.


    (-1) for XR. This is on version 4.3.0.


    Cheers,

    AB.

     

  • Yes, you must manually type this command in ALL of the boxes that are in the path. If you are doing option Inter-AS option B, the PEs dont have routing info to the other PEs, so the PEs with mVPNs should have it configured under their VRF and not under the global PIM process. The P routers have it in their global PIM process of course.

    If you are running Option C, and the PE devices have routing information to get to the other PEs in other ASs, then you should use the command on the global PIM process and not on the VRF aware process on the PE. 

    This makes sense though...why would I send you a PIM packet advertising a vector when I don't know that you support it? This is signaled through the PIM hellos (support for Vector).  It uses a new PIM packet format. 

    Also, how would a PE router know if the router upstream of him is running BGP or has reachability information? There is no way to know this (from a router's perspective). The only way is to just hard code it on all routers along the path. 

    Have you used BGP Connector with IOS-XR? I have tested both BGP Connector and PIM Vector on IOS...Looks like I should also do it on XR to find out any caveats.

    Pablo

  • I dont agree with you here. First, BGP Connector attribute (which is advertised with VPNv4 prefix) is used to identify the tunnel endpoint and hence used for RPF-check.

    PIM Vector is carried in PIM so that P-routers can forward PIM Join/Prune messages for PE in remote AS to the Vector (in other words to the ASBR).

    In IOS, you just enable PIM Vector on PEs using the command ip multicast vrf <vrf> rpf proxy rd vector. The PEs set the Vector address based on the MDT NLRI received from the ASBR. Setting Vector address statically just means broken XR code.

    Cheers,

    AB.

  • What don't you agree with? 

    All I asked about the BGP Connector was if you had tried it...not really relating to the Vector thing we were talking about (it was just a question, not a suggestion)

    Why does it mean broken XR code? IOS has the same behavior (you have to manually configure it). 

     

    "Because the PIM Vector uses a completely new source-encoding type, the upstream routers (i.e.,

    toward the source) must be able to receive and parse the Join. A new PIM Hello option has been

    introduced to signal PIM Vector capability. The PIM Vector will only be included in the Join message

    if all neighbors on an interface possess the PIM Vector capability."

     

     

     

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