Another v6 question

Justin M. Streiner streiner at
Tue Jan 25 09:59:21 CST 2011

On Tue, 25 Jan 2011, Max Pierson wrote:

>> From the provider perspective, what is the prefix-length that most are
> accepting to be injected into your tables??  2 or so years ago, I read where
> someone stated that they were told by ATT that they weren't planning on
> accepting anything smaller than a /32. So what if I get my shiny new /48
> from ARIN and am already multi-homed??? Does ATT not want my business (which
> they wouldn't get if the first place, but for argument sake, yes, I chose to
> pick on ATT, sorry if I offended anyone :)  I already see /40's /48's ,etc
> in the v6 table, so some folks are allowing /48 and smaller, so what is the
> new /24 in v6?

>From what I've seen, both in terms of policy and practice is that most 
people are considering /48 to be 'the new /24'.  A number of providers 
haven't published their v6 policies yet (at least in any place that's easy 
to find), but it looks like based on policy alone, NTT and Verizon will 
accept /48s.

Also, I don't know that the number of v6 prefixes will get completely out 
of control for a while.  Many of the bigger consumers of v4 space are 
getting (or have gotten) initial v6 assignments that are large enough to 
satisfy their space needs for some time, so the number of v6 prefixes 
being announced to provide connectivity to a given number of ISP 
customers should actually go down somewhat.  For example, Comcast has 
several /8s of v4 space, and they are announcing a /29 into the global v6 
table at the moment.  That could certainly change as they ramp up their 
deployment of v6, but I still think the number of v6 prefixes compared to 
v4 will be net-negative for a long time.


More information about the NANOG mailing list