Current Consensus on IPv6 Customer Allocation Size

Mark Blackman mark at
Thu Aug 2 11:07:45 CEST 2012

On 1 Aug 2012, at 23:13, Daniel Roesen <dr at> wrote:

> On Wed, Aug 01, 2012 at 10:12:55PM +0100, Mark Blackman wrote:
>> More than 256 subnets in the home? Who would want to manage all of that?
>> I can't see more than about 16 subnets at a single residential
>> address with a single family
> "I think there is a world market for maybe five computers."
> - Thomas Watson, Chairman, IBM, 1943
> "There is no reason why anyone would want a computer in their home."
> - Ken Olsen, Founder, DEC, 1977
> "640K should keep everyone happy for the next 10 years"
> - Bill Gates, Founder, Microsoft, 1981
> "4 bits for home subnetting should be more than enough"
> - any takers?

Comcast alone has around 2^26 customers (45.2 million)

"24.4 million cable customers, 14.7 million high-speed Internet
customers and 6.1 million digital voice customers in 39 states and the
District of Columbia."

Comcast's only allocation that I can see is a /31,

They're going to need a much bigger IPv6 allocation to give all ~2^26
customers a /48 allocation, and they can't even quite give them all a
/56 out of their current allocation.

Did they get their initial allocation wrong? Should all 45 million get a
/48 ?

I'd guess that these numbers are much bigger by one or two orders of
decimal magnitude in Asia.

- Mark

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