Re: draft-ietf-v6ops-addcon-03.txt ... ULAs of shorter-than-/48 and ULA multicast scope matching ...

[Tim Chown <tjc@ecs.soton.ac.uk>]

On Tue, Mar 13, 2007 at 10:35:42PM +1030, Mark Smith wrote:
> > 
> > Well, think a little bigger than a /44 example?   What would you say then?
> > 
> 
> We'll, I've understood that a /48 was sized to be big enough for
> nearly everybody, and those who require larger would only maybe need
> a /47 or a /46. A /44 seems extremely large to me (around 1M subnets),
> so I'm wondering whether going much shorter is that practical - unless
> we might be talking about a service provider, who might have 1M+
> distinct subnets, who then maybe would want to have fully matching ULA
> subnets. If they're that size, I'd be assuming they'd be aggregating
> internally fairly aggressively for both global and ULAs, just to cope
> with router limitations. Possibly they might not deploy ULAs for all of
> those subnets either - without putting much thought into it, I don't
> think there would be that much benefit in assigning ULA subnets to
> their customer attachment network edge links. (Possibly SPs may not
> deploy ULAs at all, or at least only for their internal corporate /
> support networks, not the customer traffic carrying links.)

Fair comment.   I guess we're also nibbling here at the 'what's a site'
question.  I don't know where Thomas Narten's 3177-bis proposal got to,
but if end sites were allocated a /56 you'd probably want a /56 ULA...

Let's see what others on the list think.

-- 
Tim