And Now for Something Completely Different (was Re: IPv6 news)

Tue Oct 18 00:44:33 UTC 2005

Thus spake "Fred Baker" <fred at cisco.com>
> The RIRs have been trying pretty hard to make IPv6 allocations be one 
> prefix per ISP, with truly large edge networks being treated as 
> functionally equivalent to an ISP (PI addressing without admitting it  is 
> being done). Make the bald assertion that this is equal to one  prefix per 
> AS (they're not the same statement at all, but the number  of currently 
> assigned AS numbers exceeds the number of prefixes under  discussion, so 
> in my mind it makes a reasonable thumb-in-the-wind- guesstimate), that is 
> a reduction of the routing table size by an  order of magnitude.
>
> If we are able to reduce the routing table size by an order of  magnitude, 
> I don't see that we have a requirement to fundamentally  change the 
> routing technology to support it. We may *want* to (and  yes, I would like 
> to, for various reasons), but that is a different  assertion.

If we reduce the average number of prefixes per AS by an order of magnitude, 
IMHO the result will be that there will be an order of magnitude growth in 
the number of ASes.  We're just going to trade one problem for another.

What we need is an interdomain routing system that can either (a) 
drastically reduce the incremental cost of additional prefixes in the DFZ, 
or (b) move the exist cost out of the DFZ to the people who want to 
multihome.  Both probably mean ditching BGP4 and moving to some sort of 
inter-AS MPLS scheme, but it will never see the light of day unless it 
allows leaving hosts and intra-site routing intact (i.e. hop-by-hop routing 
and a single prefix per site).  This last is why shim6 is DOA.

S

Stephen Sprunk        "Stupid people surround themselves with smart
CCIE #3723           people.  Smart people surround themselves with
K5SSS         smart people who disagree with them."  --Aaron Sorkin 