v6 subnet size for DSL & leased line customers

Mon Dec 24 17:10:05 UTC 2007

Joe Greco wrote:
>> It's likely that the device may choose to nat when they cannot obtain a
>> prefix... pd might be desirable but if you can't then the alternative is
>> easy.
> 
> I thought we were all trying to discourage NAT in IPv6. 

You/we are... Which is why you really need PD, and cpe needs to be able
to hand out /64s on request to downstream devices. Not surprisingly that
will drive subnetting in the home. presently, plugging in more
gateway/router devices results in multiple layers of nat and huge
amounts of unnecessary complexity in the home network.

> Clearly, NAT
> solves the problem ... while introducing 1000 new ones.  :-/

Sure, we don't have a reasonable mechanism for ipv4 devices to pull
address space out of thin air. We do have one in ipv6. This is a problem
that equipment makers (as much as randy hates them) will have to
address. It doesn't take much imagination to figure out how they will
address it given a lack of alternatives.

> ... JG