v6 & DSL / Cable modems [was: Private use of non-RFC1918 IP space (IPv6-MW)]

Mikael Abrahamsson swmike at swm.pp.se
Thu Feb 5 06:59:55 UTC 2009

On Wed, 4 Feb 2009, Joe Abley wrote:

> I see people predicting that giving everybody a /56 is insane and will 
> blow out routing tables. I don't quite understand that; at the regional 
> ISP with which I am most familiar 40,000 or so internal/customer routes 
> in BGP, and I have not noticed anything fall over. This is 2008: we are 
> not dealing with routers maxed out with 256MB of RAM. And this is 
> without any attempt to aggregate per LNS, or per POP.

What you do is that you do /40-44 per router or so and announce this to 
the rest of the network, then internally from that you assign /48 to /56 
per customer out of that block.

IPv6 enables us to lower address use and get less routes in the core 
network (both within the ISP and globally).

Mikael Abrahamsson    email: swmike at swm.pp.se

More information about the NANOG mailing list