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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 Adrian,

    In the "global" configuration mode of BGP we configure IPv4 unicast which is activated by default. All the other stuff like IPv6 unicast/multicast, IPv4 multicast and VPN routes are disabled by default so that's why we need to activate them. I guess it makes sense, BGP is/was mostly used for IPv4 unicast and not everyone uses all the other address families.


  3. 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.


  4. 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.

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