Re: Comments on RIP-II protocol and MIB specification.

[Fred Baker <[e-mail]>]

>> Routing Domains solve a different problem.  There are cases where two
>> or more Administrative Domains (ADs) come together on one wire.  Say
>> we have a DMZ where there are two routers each from regional providers
>> A and B (A1, A2, B1, B2) and a router from the national provider C
>> (C1).  The regionals use this network to connect the two halfs of
>> their regional together as well for connecting to the other regional
>> and to the national provider.  So they want to be able to run an IGP
>> between their routers (A1 to A2 and B1 to B2).  If they use different
>> IGPs everything is OK.  If they want to use the same IGP, you need
>> Routing Domains.
>> 
>> To complicate things even further, say the national provider has
>> agreed to listen to the IGPs of each of the regionals and implement
>> their policy for them.  So router C1 must be capable of listening to
>> both IGPs and distinquishing between them.

It seems to me that this is exactly the problem that BGP is designed to
solve, and in the IGP case is best handled using filters of the form
"accept/propagate routes to <mumble> from <neighbor>", which is all BGP
is anyway.

>> Yes, some of this can be implemented with multiple IP subnets on a
>> given wire.  But I believe that would be harder for operations people
>> to understand and support, and it still doesn't solve the problem of
>> managing such a setup with SNMP.  And the majority of forwarding
>> engines that gated supports do not support multiple subnets on one
>> wire.

I obviously can't comment on UNIX provisions; I don't run UNIX.  I can
say that I have a lot of customers who are doing exactly what you're
talking about using multiple subnets on a wire, and since they're using
my box and the only way to manage it is with SNMP, I guess it must be
SNMP manageable. If you used BGP, you could probably use the BGP MIB.

I dunno, it seems to me that this is *way* beyond the charter, which
fixing a few problems with RIP and remaining interoperable. We are
defining an external gateway protocol.