[141550] in North American Network Operators' Group
Re: Cogent IPv6
daemon@ATHENA.MIT.EDU (Chris Adams)
Wed Jun 8 23:33:34 2011
Date: Wed, 8 Jun 2011 22:33:29 -0500
From: Chris Adams <cmadams@hiwaay.net>
To: "nanog@nanog.org" <nanog@nanog.org>
Mail-Followup-To: Chris Adams <cmadams@hiwaay.net>,
"nanog@nanog.org" <nanog@nanog.org>
In-Reply-To: <BANLkTikJjjyy82XEjkesrh_3yaDixqVQNQ@mail.gmail.com>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
Once upon a time, William Herrin <bill@herrin.us> said:
> Now, as to why they'd choose a /112 (65k addresses) for the interface
> between customer and ISP, that's a complete mystery to me.
I had to ask this here a while back, so I can now share. :-)
IPv6 addresses are written as 8 16-bit chunk separated by colons
(optionally with the longest consecutive set of :0 sections replaced
with ::). A /112 means the prefix is 7 of the 8 chunks, which means you
can use ::1 and ::2 for every connection.
Of course, just because you allocate a /112 (or shorter) in your
database doesn't mean you have to use it. You could also allocate a
/112 for a point-to-point link and use a /127 (e.g. addresses ::a and
::b).
--
Chris Adams <cmadams@hiwaay.net>
Systems and Network Administrator - HiWAAY Internet Services
I don't speak for anybody but myself - that's enough trouble.
