At 12:49 PM 12/10/99 -0500, Keith Moore wrote:
>> > There is also a potential scaling issue of using multiple addresses
>> > as general purpose multihomging mechanism. This is because if this
>> > is the case, most of the Internet hosts will end up with multiple
>> > addresses.
>>
>> I don't see why this is inherently a problem.
>
>it's a problem because it's essentially asking the sending host to do
>routing in the absence of any routing information.
Well, it is a problem that you have to solve anyhow, as soon as the same
service is available from multiple servers accross the Internet. What is
the difference, from a host point of view, between choosing among interface
addresses aa, ab, ac, ad of server A and choosing between interface
addresses aa, bb, cc and dd of servers A, B, C and D? If you wanted to
solve the latter at the routing level, then you should allocate an anycast
address to every group of servers that provide the same service (e.g. a
copy of the same DNS domain, of the same Web sites, or a gateway to the
same mail systems.) Now *that* would be an interesting routing problem --
BGP tables with approximately 3 million entries...
Let's face it: the odds of solving a scaling problem from the edges of the
network, from the hosts, are much better than the odds of scaling the
routing system.
-- Christian Huitema
