Point 2 point IPs between ASes

Wed Jun 28 21:09:25 UTC 2017

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On 2017-06-28 17:03, William Herrin wrote:

> The common recommendations for IPv6 point to point interface numbering are:
> 
> /64
> /124
> /126
> /127

I thought the only allowed subnet prefix lengths for IPv6 were /64 and
/127.  RFC 4291 states:

   For all unicast addresses, except those that start with the binary
   value 000, Interface IDs are required to be 64 bits long and to be
   constructed in Modified EUI-64 format.

(and addresses starting with 000 are only used for special things,
like the localhost address ::1).  And then RFC 6164 adds /127 to
the allowed prefix lengths.

I know that many devices allow you to configure any subnet size,
but is there any RFC allowing you to use e.g. /124 or /126?

	/Bellman
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