Path: utzoo!attcan!utgpu!watmath!iuvax!mailrus!csd4.csd.uwm.edu!bionet!lear
From: lear@NET.BIO.NET (Eliot Lear)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: Naive questions about subnets & domains
Message-ID: 
Date: 16 Aug 89 16:04:47 GMT
References: <1072@adobe.UUCP>
Organization: Natl Computer Resource for Mol. Biology
Lines: 37


This is more of a question than an answer, but you might find it
interesting...

It would seem to me that whether you stick your other sites in your
class B depends on whether those remote sites will eventually have
entry points to outside networks.  Existing routing technology is
pretty wretched about such things.  Case and point:

Suppose you have a network that consists of two or more locations,
that looks something like the following:


	Site A			 T 1		Site B
	Highspeed Internet	<--->		Backup Link
	Link

Well, what happens if the T1 goes down?  If each site has a different
net number, then with the blessing of appropriate routing gods, one
might even route through the Internet to get around the break
(forgetting policy issues, for the moment).  If you use the same
network, then Site A continues to advertise it as before, and the
chances are that Site B will most likely be screwed, depending on what
routing protocol is in use.

My question:

Does anyone see an answer to this problem, or have I defined the
problem incorrectly?

One way to handle such a break would be to transmit a subnet mask with
the route.  Yes, this would increase routing traffic, but one would
only do such a thing when attempting to correct a situation like the
one I described.
-- 
Eliot Lear
[lear@net.bio.net]