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Notable Replies

  1. Hi Rene,
    Can you please explain why do neighbors need to be activated ? In the old syntax ( without address families) these was no "activate". After declaring the neighbors they were activated by default ? But in the new format they are "born" not activated so we need to activate them ?
    Thank you.

  2. Hi Thomas,

    1. I think yes, it makes more sense to use "show bgp ipv6" than "show ip bgp ipv6" somehow since the "ip" parameter normally refers to IPv4. On the other hand, you could establish a BGP peering over IPv4 and exchange IPv6 prefixes...it's a bit confusing :slight_smile:

    2. The cleanest solution is probably to use two different address families, one for IPv4 and another for IPv6 and then do a peering for each. Something like this:

    router bgp 1
    neighbor remote-as 2
    neighbor 2001:DB8:0:12::2 remote-as 2

    address-family ipv4
    neighbor activate
    no neighbor 2001:DB8:0:12::2 activate

    address-family ipv6
    neighbor 2001:DB8:0:12::2 activate

    This gives you a nice separation between the two protocols and it's probably also easier if you add route-maps or use any other filtering method, you can use one route-map for IPv4 and another for IPv6.


  3. tkalis says:

    Thank you Rene for the detailed reply. Just so I fully understand all the options, I can technically have the following:

    1. MP-BGP arrangement with IPv4 neighbor establishment and then advertisement of both IPv4 and IPv6 prefixes
    2. MP-BGP arrangement with IPv6 neighbor establishment and then advertisement of both IPv4 and IPv6 prefixes
    3. MP-BGP arrangement with both IPv4 and IPv6 neighbor establishment and then advertisement of IPv4 prefixes within IPv4 address family and IPv6 prefixes within IPv6 address family

    Please confirm when you have a chance. Many thanks.

  4. Hi Tim,

    This shouldn't be a problem, it's hard to find a Cisco router nowadays that doesn't support MP-BGP.

    IPv6 multicast is only one of the address families that are supported nowadays:

    R1(config)#router bgp 1
    R1(config-router)#address-family ?
      ipv4      Address family
      ipv6      Address family
      l2vpn     Address family
      nsap      Address family
      rtfilter  Address family
      vpnv4     Address family
      vpnv6     Address family


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