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From: raj@hpindwa.cup.hp.com (Rick Jones)
Newsgroups: comp.dcom.sys.cisco
Subject: Switching g/w's midstream...
Message-ID: <54680003@hpindwa.cup.hp.com>
Date: 5 Nov 90 23:41:14 GMT
Organization: Hewlett-Packard, Cupertino CA
Lines: 36


Also sent to the Wellfleet mailing list - you aren't seeing double... ;-)


Here is a routing/ICMP/brouter question...

Consider a set of brouters joining several subnets with more than one
brouter between any two subnets (parallel brouters) with a simple
picture looking like:

       --------------------  subnet A  ----------------------
                   |                          |
              ------------              -------------
             | primary    |            | secondary   |
             |    brouter |            |     brouter |
              ------------              -------------
                    |                         |
       --------------------  subnet B  ----------------------


Now, the question is what happens when primary dies?

I assume that the 'b' part of the brouters will re-spanning-tree so
that all the non-IP traffic will continue to flow. Will a similiar
thing happen up at the IP routing layer? For example, will secondary
send-out an ICMP redirect (broadcast?) to get hosts to switch
gateways?

I am really interested in solutions that do not involve much if any
intelligence in the hosts except the ability to process an ICMP
redirect 'the right way' ;-)

Is this 'IP spanning-tree' kind of a thing available in any particular
routing protocol, all protocols? Vendors?  etc...

rick jones