In a message written on Fri, Nov 19, 2004 at 05:15:26PM +0100, Lars Erik Gullerud wrote:
While that would seem logical for most engineers, used to /30 or /31 ptp links in IPv4 (myself included), that does not in fact seem to be the way things are currently done in IPv6, unless something changed (again) while I wasn't paying attention... /64 is the minimum subnet size, even for ptp-links - there was even an RFC published relating to the use of /127's (or, should I say, the recommendation to "don't to that"), namely RFC3627 (aka "Use of /127 Prefix Length Between Routers Considered Harmful"). But, you can still get 65536 ptp links out of a single /48 of course.
FWIW, my test networks have always been configured with /126's, and have never had an issue. With the exception of auto-configuration, I have yet to see any IPv6 gear that cares about prefix length. Configuring a /1 to a /128 seems to work just fine. If anyone knows of gear imposing narrower limits on what can be configured I'd be facinated to know about them. -- Leo Bicknell - bicknell@ufp.org - CCIE 3440 PGP keys at http://www.ufp.org/~bicknell/ Read TMBG List - tmbg-list-request@tmbg.org, www.tmbg.org