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

[Jeffrey C Honig <[e-mail]>]

You are assuming that Route Tags and Routing Domains are related, they
are not.


You basically have the concept of RouteTag correct.  I can import
external routes into a RIP domain from several different external
attachement points, each using a different tag.  At each external
attachement point I can decide which, if any, external routes to
export based on the tag.  If I do not wish to announce any external
routes, I can just announce those that have a tag of zero.  Or maybe
you want to tag each departments routes differntly and only announce
some of those externally.


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.


Gated has always implemented the capablility to unicast RIP updates to
certain routers across a broadcast network.  This is used when it is
desired to restrict knowledge of certain routes to a subset of the
routers on a given network.  Say the network is a campus backbone
where the departments run their own routers.  One department is in two
locations and wants to have connectivity for certain networks within
it's department, but not make them known to the rest of the campus.

I envision RIP-II Routing Domains as a replacement for this ability to
unicast specific information to specific routers.


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.

Jeff