autoroute announce and ipv6 bgp peering.





I have MPLS TE (dynamic) between  RA and RC and at the same time RA and RC has ipv6 ebgp peering.

The moment i configure autoroute announce command on RC . ipv6 ibgp peering it going down between RA and RC.




  • if you are running isis as your igp, do you have multitopology enabled on all routers?

  • router isis

    address-family ipv6



    just double check the syntax

  • router isis
     metric-style wide
     address-family ipv6
     mpls traffic-eng router-id Loopback0
     mpls traffic-eng level-1

    this I will have to define on all router's RA RB and RC ?

  • Multitopology needs to be on all all ios routers. IOS XR is on by default.

  • what about IOS-XR ? What is the syntax in IOS-XR?


  • ISIS multitopologies is enabled by default on IOS-XR and does not follow IOS logic (as with other protocols as well):




  • In XR the default is multitopology:


    router isis

     is-type level-2

     net 39.0014.0000.0000.1414.00

     log adjacency changes

     address-family ipv4 unicast

      metric-style wide

      mpls traffic-eng level-2

      mpls traffic-eng router-id Loopback0


     address-family ipv6 unicast

      metric-style wide


  • I'm curious about this weird behavious so i try it on GNS3 :

    R4--R5--R6 with ISIS Single topology (default), Level-1, TE dynamic on both direction, but BGP IPv6 peering stay up when add autoroute announce.



    R4 config:

    router isis

     net 47.0456.0000.0000.0004.00

     is-type level-1

     metric-style wide

     passive-interface Loopback0

     mpls traffic-eng router-id Loopback0

     mpls traffic-eng level-1




    router bgp 100

     no synchronization

     bgp log-neighbor-changes

     neighbor remote-as 100

     neighbor update-source Loopback0

     no auto-summary


     address-family ipv6

      no synchronization

      network 2002:4:4:4::4/128

      neighbor activate


    interface Tunnel46

     no ip address

     tunnel source

     tunnel mode mpls traffic-eng

     tunnel destination

     tunnel mpls traffic-eng autoroute announce

     tunnel mpls traffic-eng path-option 1 dynamic




    Name: R4_t46                              (Tunnel46) Destination:


        Admin: up         Oper: up     Path: valid       Signalling: connected

        path option 1, type dynamic (Basis for Setup, path weight 20)

     Config Parameters:

        Bandwidth: 0        kbps (Global)  Priority: 7  7   Affinity: 0x0/0xFFFF

        Metric Type: TE (default)

        AutoRoute announce: enabled  LockDown: disabled Loadshare: 0        bw-based

        auto-bw: disabled


    Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd         4          100      12      13        2    0    0 00:06:54        1

    I try BGP peering with IPv6 address but it's stay up too.  

    Did i miss something here ?


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