RE: Multihoming and what we discussed in Atlanta

["Aldrin Isaac" <aisaac@bloomberg.com>]

% draft-kurtis-multihoming-longprefix-00
% 6.1 Aggregation effects with the current allocation policies
%   ....
%   improved.  With the proposal for multihoming IPv6 as described in
%   this document, the potential for the same routing table growth
%   explosion as we have today exists.  However, given that the
current
%   allocation blocks to ISPs are blocks with 32 bit long prefixes,
one
%   of these blocks will fit the current address assignments of most
%   ISPs.  This means that the routing table will be inherently small
to
%   start with.  Even if all ASes that are active today where to
announce
%   IPv6 address space, it would only be around 14 000 routes.  Almost
%   90% less of the current routing table.  This means that we have
quite
%   a lot of breathing space before we starting running into the same
%   scalability problems as today.  This is due to the current
%   allocations.  Doing multihoming by announcing longer prefixes out
of
%   allocated blocks will make the routing larger but looking at the
%   current amount of multihomed networks, this should not pose a
%   problem.

IMHO, for this form of multihoming, multihomers should *not* use
prefixes that that are part of the allocation of any of the ISPs over
which it multihomes.  A multihomers address should come from
well-known managed PI blocks.  Using part of an ISPs allocation
results in inefficient routing, unneccessary fragmentation of ISP
address blocks, and more complex policies for ISP peering.

-- aldrin