nanog mailing list archives

Re: Cogent IPv6


From: Aftab Siddiqui <aftab.siddiqui () gmail com>
Date: Thu, 9 Jun 2011 11:58:56 +0500

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).

Still that doesn't give any reason to provide /112 for point to point
connectivitiy. Seriously, I'm peering with a transit provider with /126 and
when I asked for a reason they said, ease of management. How come Subnetting
/32 to /126 is ease of management??.... thats quite difficult to understand.
This debate is there fore quite a long time but everytime it pops up I
feel so uncomfortable with this granular subnetting.

Regards,

Aftab A. Siddiqui


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