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From: henry@utzoo.UUCP (Henry Spencer)
Newsgroups: net.news,net.news.adm,net.mail
Subject: Re: ihnp4 problems
Message-ID: <7079@utzoo.UUCP>
Date: Thu, 4-Sep-86 12:17:14 EDT
Article-I.D.: utzoo.7079
Posted: Thu Sep  4 12:17:14 1986
Date-Received: Thu, 4-Sep-86 12:17:14 EDT
References: <782@laidbak.UUCP>
Organization: U of Toronto Zoology
Lines: 17

> To: a!b!c!d!e!user
> 
> passes through a and b ok, arrives at c.  c has both d and e as
> neighbors.  It is acceptable for c to send the mail direct to e...

Not necessarily.  Life would be much simpler if all links were of equivalent
quality -- certainly pathalias wouldn't have to work so hard -- but that's
not the way it is.  It's not uncommon for the c!d!e path to be *much* better
than the c!e path, so large or time-critical mail might not want to be
gratuitously rerouted through a poorer link.  If one must reroute, the right
criterion is that the c!e route should be at least as fast and, if the mail
is large, that it should have comparable bandwidth.  It would be nice to
factor some measure of reliability into this as well, but getting the data
for that is hard.
-- 
				Henry Spencer @ U of Toronto Zoology
				{allegra,ihnp4,decvax,pyramid}!utzoo!henry