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From: mike@BRL.ARPA (Mike Muuss)
Newsgroups: comp.protocols.tcp-ip
Subject: Re:  Multiple Internet addresses
Message-ID: <8709162045.aa02635@SEM.BRL.ARPA>
Date: Wed, 16-Sep-87 20:45:08 EDT
Article-I.D.: SEM.8709162045.aa02635
Posted: Wed Sep 16 20:45:08 1987
Date-Received: Sat, 19-Sep-87 14:24:34 EDT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The ARPA Internet
Lines: 17

The strategy that we have used at BRL (implemented by J. Pistritto)
for many years now is to run a simple program on each local net host
(called "router") that is given a prioritized list of "default routes".
The highest priority route that meets certain maximum roundtrip times (<
5 sec) and maximum packet loss rates (50%) is selected.  When the
highest priority route is not selected, all higher priority ones are
PINGed at a slow rates (once/minute).  When a higher priority path
becomes acceptable again, the default route is switched back to it.
No PINGs leave the local network, and the ping rate is very low.

4.3 BSD does the rest, handling redirects, etc., that the gateway issues,
and reconsulting the routing tables when a TCP connection is "halfway"
timed out.

We have found this strategy to work very successfully.
	FYI
	 -Mike