/128 IPv6 prefixs in the wild?

Owen DeLong owen at delong.com
Thu Dec 15 10:42:32 UTC 2011

You'll still probably carry the /128 loopbacks in your IGP to deal with your iBGP mesh.


On Dec 14, 2011, at 9:54 PM, Glen Kent wrote:

> Hi,
> In the service provider networks, would we usually see a large number
> of /128 prefixs in the v6 FIB tables?
> In an IP/MPLS world, core routers in the service provider network
> learn the /32 loopback IPv4 addresses so that they can establish
> BGP/Targetted LDP sessions with those. They then establish LSPs and
> VPN tunnels. Since we dont have RSVP for IPv6 and LDP for IPv6 (not
> yet RFC) we cannot form MPLS tunnels in a pure IPv6 only network.
> GIven this, would v6 routers have large number of /128 prefixes?
> What are the scenarios when IPv6 routers would learn a large number of
> /128 prefixes?
> I would presume that most IPv6 prefixes that the routers have to
> install are less than /64, since the latter 64 is the host part. Is
> this correct?
> Glen

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