IPv6: numbering of point-to-point-links

Gary Buhrmaster gary.buhrmaster at gmail.com
Mon Jan 31 15:52:19 CST 2011

On Mon, Jan 31, 2011 at 09:13, Blake Hudson <blake at ispn.net> wrote:
> I setup a p2p /127 link and found that BGP would not peer over the link;
> Changing to /126 resolved the problem. I never looked into it further
> because I had intended to use /126 from the start. My guess is that
> while BGP should be a unicast IP, Cisco's implementation uses an anycast
> in some cases, disregarding the configured unicast address.
> Just one practical example...

I suspect this is very platform/version specific, as I have run BGP
on a Cisco 6500 (SXI<mumble>) to a Juniper MX and we had no
trouble with a /127 (although prepared to move to a /126 or whatever
if needed).  As always, your environment will vary.  I would open
a TAC case on the principal that it should work.

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