[183569] in North American Network Operators' Group
Re: IPv6 Subscriber Access Deployments
daemon@ATHENA.MIT.EDU (Matthew Kaufman)
Tue Sep 8 20:29:45 2015
X-Original-To: nanog@nanog.org
In-Reply-To: <26760.1441742090@turing-police.cc.vt.edu>
From: Matthew Kaufman <matthew@matthew.at>
Date: Tue, 8 Sep 2015 13:13:55 -0700
To: "Valdis.Kletnieks@vt.edu" <Valdis.Kletnieks@vt.edu>
Cc: Josh Moore <jmoore@atcnetworks.net>, "nanog@nanog.org" <nanog@nanog.org>
Errors-To: nanog-bounces@nanog.org
If you can't hang 4k customers off a switch, why does IPv6 need so many bits=
for the host portion?
Matthew Kaufman
(Sent from my iPhone)
> On Sep 8, 2015, at 12:54 PM, Valdis.Kletnieks@vt.edu wrote:
>=20
> On Tue, 08 Sep 2015 19:40:44 -0000, Josh Moore said:
>=20
>> The question becomes manageability. Unique VLAN per customer is not alway=
s
>> scalable. For example, only ~4000 VLAN tags. What happens when you have m=
ore
>> than that many customers?
>=20
> If you're hanging 4K customers off the same switch, you probably have bigg=
er
> issues than running out of VLAN tags...
>=20
>> We are talking very, very, small customers here. SOHO to say the most.
>> /64 should be more than sufficient for their CPE router.
>=20
> A Linksys WNDR3800 running CeroWRT (and probably OpenWRT by now) will pref=
er to
> create multiple /64's - one for the 4 wired ports, one for private access o=
n the
> 2.4G radio, one for guest access on the 2.4, and another private/guest pai=
r
> on the 5G radio. So there is CPE gear out there now that can blow through 5=
/64s
> by default, and more if you enable VLANs.
>=20
> A /56 allocated via DHCPv6-PD would be a *minimum*. And prefixes are chea=
p,
> so you may as well hand them a /48, just in case they have a second WNDR38=
00
> at the other end of the building for coverage - because that one will then=
ask
> the upstream one for a -PD allocation. So if you give the CPE a /48, it c=
an
> keep a /56 for itself, and hand the downstream a /56, and they can each
> allocate /64s as needed.
>=20
> And remember - prefixes are cheap and plentiful, so don't bother with /52
> or /60, just split on 8-bit boundaries to make life easier for yourself...=
>=20
