🚀 go-pugleaf

In article <17201@hercules.csl.sri.com> forster@cisco.com (Jim Forster) writes:

   >> And finally, what do the routers do to route in networks with
   >> multiple routing protocols (e.g. IGRP and RIP, to pick an example,
   >> or OSPF and RIP for a harder (?) example).  Assume a topology that
   >> admits a non-trivial answer!

Okay.  I'll answer this one.  cisco provides the tools to do this.
However because of the differences in Routing protocols it is very
easy to hammer your network in a big way.  ***THIS IS NOT RECOMMENDED!***
But we are aware of the need in many cases to allow multiple routing
protocols to exist in the same network.  One example is communicating
routing information to a node running routed or gated.  Since these
daemons don't know about IGRP some other protocol needs to be used.

The mechanism supplied is the redistribute command.  I don't have
the syntax memorized and I'm at home without a manual so I'll have
to refer you to the manual and release notes.  Basically the idea
is to selectively release information learned from one routing
protocol to another.  But once again you have to be very careful
here because it is very easy to introduce non-optimal routes and
routing loops.  Earlier routing protocols are different from the more
modern ones such as IGRP and OSPF and won't have the same level of
information embedded.  Result: less informed routing decisions.

I mentioned the need to communicate to a node running gated or routed.
There are better mechanisms that allow communications of information
to these nodes.  Namely GDP (Gateway Discover Protocol, gateway in the
sense of a router).  Having hosts involved in routing decisions is in
general a bad idea.  However there are still some things that it needs
to find out and GDP supplies this information.  cisco routers have
a GDP implementation and we have a reference non-supported Unix
implementation of a gdp daemon that can run on Suns.

If you need further information about cisco products please feel
free to send a message to customer-service@cisco.com.

thank you,

-c
cire|eric

"I could have done it in a much more complicated
way", said the Red Queen, immensely proud.
			-- Lewis Carroll, Alice in Wonderland
Eric B. Decker
Token Ring Development
cisco Systems - engineering
Menlo Park, California

email:	cire@cisco.com
uSnail: 1525 O'Brien Dr.,  Menlo Park, CA  94025
Phone : (415) 326-1941, (415) 688-8241
--
cire|eric

"I could have done it in a much more complicated
way", said the Red Queen, immensely proud.
			-- Lewis Carrol, Alice in Wonderland
Eric B. Decker
Token Ring Development
cisco Systems - engineering
Menlo Park, California

email:	cire@cisco.com
uSnail: 1525 O'Brien Dr.,  Menlo Park, CA  94025
Phone : (415) 326-1941, (415) 688-8241