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