[ipv6-wg] /127 for point to point links

On Fri, 12 Feb 2010, Vegard Svanberg wrote:
> Hello. We've stumbled across a problem with a router manufacturer, which
> won't implement support for /127 prefix lengths. Now, we do have
> peering/transit partners using /127 on their p2p links. The result is
> that we either cannot peer with them, or will have to get new routers.
>
> RFC 3627 states that /127 is considered harmful, however I do feel this
> RFC confuse people since it doesn't propose a definite solution. It
> suggests a number of solutions and indicates using /64 is the right
> thing. I must say I strongly disagree on that conclusion. Wasting so
> much address space on point to point links just makes no sense to me.

The argument about wasting address space is not useful.

However, there are other arguments for using /127, especially if 
you're using e.g. SDH technology (the interface is "point-to-point" 
media).  http://tools.ietf.org/html/draft-kohno-ipv6-prefixlen-p2p-00 
describes these to some degree.  (The draft is being revised.)

-- 
Pekka Savola                 "You each name yourselves king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings