IPv6, multihoming, and customer allocations

Rick Ernst nanog at shreddedmail.com
Tue Mar 16 14:38:42 UTC 2010


Regurgitating the original e-mail for context and follow-up.

General responses (some that didn't make it to the list):
  - "There really is that much space, don't worry about it."
  - /48s for those that ask for it is fine, ARIN won't ask unless it's a
bigger assignment
  - /52 (or /56) on smaller assignments for conservation if it makes you
feel better
  - Open question on whether byte/octet-boundary assignment (/56 vs /52) is
better for some reason

I haven't seen anything on the general feel for prefix filtering.  I've seen
discussions from /48 down to /54.  Any feel for what the "standard" (widely
deployed) IPv6 prefix filter size will be?

Thanks,


On Sat, Mar 13, 2010 at 10:49 PM, Rick Ernst <nanog at shreddedmail.com> wrote:

>
> A couple of different incantations searching the archive didn't enlighten
> me, and I find it hard to believe this hasn't been discussed.  Apologies and
> a request for pointers if I'm rehashing an old question.
>
> As a small/regional ISP, we got our /32 assigned and it's time to start
> moving forward (customers are asking for it).  New hardware, updated IOS,
> etc. are in the pipe.  Discussions are beginning with our upstream providers
> for peering.  Now, what do we do?
>
> A /48 seems to be the standard end-user/multi-homed customer allocation and
> is the minimum allocation size from ARIN.  A /32 provides 65K /48s so, in
> theory, we could give each of our customers a /48 and still have room for
> growth.  A /48 also appears to be generally accepted as the the longest
> prefix allowed through filters (although /49 through /54 are also
> discussed).  Most customers, however, won't be multi-homed.
>
> Partly from an IPv4 scarcity perspective, and partly from general
> efficiency and thrift, it seems awfully silly to hand out /48s to somebody
> that may have a handful of servers or a couple of home machines, especially
> with special addressing like link-local if the hosts are not expected to be
> internet reachable (back-end servervs, etc).
>
> Based on the above, I'm looking to establish some initial policies to save
> grief in the future:
> - /52 allocations to end-users (residential, soho, etc.)
> - /48 allocations to those that request it
> - If you are going to multi-home, get your own space
>
> This is obviously a very broad brush and takes an insanely large addressing
> model and makes it even larger (assigning /52s instead of /48s) but, to me
> at least, it seems reasonable for a first-pass.
>
>  For context/scope, we currently have the equivalent of a bit more than the
> equivalent of a  /16 (IPv4) in use.
>
> Thanks,
>
>



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