Comcast Activates First Users With IPv6 Native Dual Stack Over DOCSIS

Mark Smith nanog at
Wed Feb 2 21:10:40 CET 2011

On Wed, 2 Feb 2011 08:53:24 -0500
Jared Mauch <jared at> wrote:

> On Feb 2, 2011, at 8:43 AM, Mark Smith wrote:
> >> I support and applaud the efforts that John is undertaking at Comcast.  While he may decide that a /64 is suitable for his customer base, as they commonly have a single lan. 
> > 
> > That's all their customers will ever be able to have if the customer
> > only ever gets a single /64. 
> So you don't think that a network will *ever* upgrade/alter it's technology deployment.  I hope you realize that the networks are constantly evolving and being upgraded.
> We've had to do many upgrades since our DS rollout in 2003 to solve problems.  Perhaps you have never had a router crash due to an IPv6 bug.  (I know I have.. and this week too).
> This limited view of how operator networks work is problematic as it commonly happens in the community.  I don't know how much effort it is for John to isolate the exact CMTS that a user is on, but across the many users there are and getting it all upgraded is likely a much larger task than you or I can envision/imagine.
> Instead of tearing down the choices Comcast makes, provide some constructive ideas of how it should be improved.  If your goal is DHCP-PD, then point to CM's that work well with that.

Well there's the thing. If it is one /64 per customer, not one /64
shared between all customers (via SLAAC on a single bridged segment),
that starts to suggest DHCPv6-PD might be in use.

>  He may be stuck with something closer to a bridged environment that
  may not be easy to change, etc..  I honestly have no clue and can
  speculate with the best of them.

That's exactly why I asked.

> (and if you think you can do it better in the US market, please show up, there are serious competition problems!  there are large segments where there is only cellular or satellite internet access available, and that's only ipv4 and only natted, so way worse! i wish i had 100 mil to run ftth to every home in my local area ~250k people).
> - Jared

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