North American Network Operators Group

Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical

Re: Stupid Ipv6 question...

  • From: Lars Erik Gullerud
  • Date: Fri Nov 19 11:20:04 2004

On Fri, 2004-11-19 at 16:36, Stephen Sprunk wrote:

> /127 prefixes are assumed for point-to-point links, and presumably an 
> organization will divide up a single /64 for all ptp links -- unless they 
> have more than 9,223,372,036,854,775,808 of them.

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

I'm sure Pekka or others will jump in here and correct me if this is now
out-of-date info. :)