Start accepting longer prefixes as IPv4 depletes?

Jack Bates jbates at brightok.net
Thu Dec 9 15:21:23 UTC 2010


On 12/8/2010 5:07 PM, Owen DeLong wrote:
> This assumes a 1:1 ratio between prefixes and routing policies. This is unrealistic in all but the most
> trivial of networks.
>

Yet we can achieve much closer to this with IPv6 due to looser 
allocation policies.

> Yes... It should. However, even with the reduced IPv6 routing table, there will be circumstances
> where multiple prefixes can efficiently be coalesced into common routing policies. Unfortunately,
> the current designs of IPv4 and IPv6 do not allow us to actually do so. What I am proposing
> would.

I agree it would be good, and every new person to BGP always asks why we 
don't route packets by the AS (seems like common sense). However, I 
think we'll have to wait and see on how well v6 manages with the new 
allocation policies and if the routing table for it drops to a 
reasonable level. This would be more acceptable than trying to shim on 
the v6 protocol. The problem is, once a protocol is standardized and 
implemented by the masses, changing is very difficult. It's going to be 
a bumpy road as we complete v6 transition, and I doubt anyone is looking 
forward to another change of that magnitude.


Jack




More information about the NANOG mailing list