[Xorp-users] IPv6 & BGP

Mark Handley M.Handley@cs.ucl.ac.uk
Sat, 17 Dec 2005 22:32:32 +0000


On 12/17/05, Hasso Tepper <hasso@linux.ee> wrote:
> Mark Handley wrote:
> > On 12/17/05, Kristian Larsson <kristian@juniks.net> wrote:
> > > I'm having problem setting up a v6 only BGP
> > > connection. it would seem it requires a next-hop
> > > parameter which is v4. Since I don't have v4 on
> > > this machine at all it is difficult.
> > > Please advice
> >
> > The BGP spec requires a NEXTHOP attribute in all routes, and this is
> > specified as an IPv4 address.  It needs this even if you're running
> > IPv6 only, but it shouldn't be used for the routing calculation.  I've
> > not tried it (probably Atanu has) but you should be able to specify
> > 10.0.0.1 or something similar.
>
> Sorry, but this is nonsense.
>
> From draft-ietf-idr-rfc2858bis-07.txt (the same text is there in the
> RFC2858 as well):
>
> "An UPDATE message that carries no NLRI, other than the one encoded in
> the MP_REACH_NLRI attribute, SHOULD NOT carry the NEXT_HOP attribute.
> If such a message contains the NEXT_HOP attribute, the BGP speaker that
> receives the message SHOULD ignore this attribute."

You're correct - I misremembered.  I should have checked before replying.

 - Mark