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From: sater@cs.vu.nl (Staveren van Hans)
Newsgroups: comp.protocols.tcp-ip,comp.protocols.tcp-ip.domains
Subject: parallel networks routing question
Message-ID: <7042@star.cs.vu.nl>
Date: 29 Jun 90 14:54:42 GMT
Sender: news@cs.vu.nl
Lines: 33

Suppose (part of) a network looks like this

  ---------------------------------------------------------  network A
		|				|
	-----------------		-----------------
	|      A.1      |		|      A.2	|
	|		|		|		|
	|      B.6	|		|      B.7      |
	-----------------		-----------------
		|				|
  --------------------------------------------------------- network B

so two multihomed hosts connected with parallel networks.
Further suppose that network B is preferable to network A, because of
load, or because it is 10x as fast (FDDI vs Ethernet).
How would one set up addressing and routing for such a configuration?

Using the DNS address lookup you get two addresses for each machine,
but most software doesn't understand that currently and only uses the
first one. Now the documentation suggests that you can order the
addresses so that certain preferred networks come in front, but looking
at our bind source code shows that that is not implemented.

Ideally this should be done by the routing layer of course, but current
routing software will probably send a packet for A.2 onto network A, unless
a host route for A.2 points to B.7. You can of course set up all these
routes by hand, but if the network size increases this gets to be too
much trouble.

How do people solve this? Do people actually have situations like this
already? Inquiring minds want to know.

	Hans van Staveren