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.
So I'm not sure what to do here. I have to convince someone; either our partners or the router manufacturer. I have the impression that /127 is used widely out there.
RFC 3627 is informational RFC. Does not describe any strict rules. Read the RFC and understand /127 is harmful only in certain cases: poin-to-point link + usage of subnet anycast. Other problems might exist as described in section 5. Also Have a look at: http://www.ietf.org/id/draft-kohno-ipv6-prefixlen-p2p-00.txt Janos Mohacsi Head of HBONE+ project Network Engineer, Deputy Director of Network Planning and Projects NIIF/HUNGARNET, HUNGARY Key 70EF9882: DEC2 C685 1ED4 C95A 145F 4300 6F64 7B00 70EF 9882