Question about IPAM tools for v6

Sam Wilson Sam.Wilson at
Mon Feb 3 13:11:45 CET 2014

On 3 Feb 2014, at 11:58, Tim Chown <tjc at> wrote:

> On 3 Feb 2014, at 11:32, Sam Wilson <Sam.Wilson at> wrote:
>> On 3 Feb 2014, at 11:17, Nick Hilliard <nick at> wrote:
>>> On 03/02/2014 11:11, Sam Wilson wrote:
>>>> Let me de-lurk and make the obvious point that using standard Ethernet
>>>> addressing would limit the number of nodes on a single link to 2^47, and
>>>> that would require every unicast address assigned to every possible
>>>> vendor.  Using just the Locally Administered addresses would limit you
>>>> to 2^46.
>>> it bothers me that I can't find any switch with 2^46 ports.
>>> Damned vendors.
>> The back of my envelope says that with my vendor of choice and a 4-deep tree (7-hop old-style STP limit) of 384-port switches I can't get more than about 2^34 edge ports.  Very disappointing.  That would need approximately 57 million routers, though, and 170 GW of electrical power, not counting the cooling requirements.  
> That's a lot of hamsters.

Turns out it's more hamsters than we have in the UK.  <>


Sam Wilson
Communications Infrastructure Section, IT Infrastructure
Information Services, The University of Edinburgh
Edinburgh, Scotland, UK

The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.

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