IPv6 end user addressing

Frank Bulk frnkblk at iname.com
Fri Aug 5 17:56:18 CDT 2011

Let's clarify -- /48 is much preferred by Owen, but most ISPs seem to be
zeroing in on a /56 for production.  Though some ISPs are using /64 for
their trials.


-----Original Message-----
From: Owen DeLong [mailto:owen at delong.com] 
Sent: Friday, August 05, 2011 12:21 PM
To: Brian Mengel
Cc: nanog at nanog.org
Subject: Re: IPv6 end user addressing

/56 is definitely preferable to /64, but, /48 really is a better choice.

/56 is very limiting for autonomous hierarchical deployments.

It's not about number of subnets. It's about the ability to provide some
in the breadth and depth of bit fields used for creating hierarchical


On Aug 5, 2011, at 9:17 AM, Brian Mengel wrote:

> In reviewing IPv6 end user allocation policies, I can find little
> agreement on what prefix length is appropriate for residential end
> users.  /64 and /56 seem to be the favorite candidates, with /56 being
> slightly preferred.
> I am most curious as to why a /60 prefix is not considered when trying
> to address this problem.  It provides 16 /64 subnetworks, which seems
> like an adequate amount for an end user.
> Does anyone have opinions on the BCP for end user addressing in IPv6?

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