North American Network Operators Group

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

  • From: Stephen Sprunk
  • Date: Mon Oct 17 20:49:50 2005

Thus spake "Fred Baker" <[email protected]>
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.


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