Path: utzoo!utgpu!watmath!iuvax!cica!tut.cis.ohio-state.edu!XEROX.COM!vanMelle.pa
From: vanMelle.pa@XEROX.COM
Newsgroups: comp.sys.xerox
Subject: Re: spp.user.timeout
Message-ID: <890830-105153-5679@Xerox>
Date: 30 Aug 89 17:51:00 GMT
References: <welch@cis.ohio-state.edu>
Organization: Info-1100 Mailing List
Lines: 23

This variable is used mainly for two, perhaps incompatible, measures:

1) It is an upper bound on the "round trip time estimate" that Lisp makes.
An SPP connection maintains a round trip estimate based on how long it
takes the other end to ack a packet we send.  This estimate is used so as
to have a guess about how long we should wait without a response before
deciding that the other end missed our packet and we should try again.

2) Lisp waits at least this long when trying to initially establish a
connection before deciding that the other server is not there.  The actual
timeout can be larger if the server is far away: it is the larger of
spp.user.timeout and 3000*#hops.

So raising it might be good if you're having a hard time connecting to
servers; if not, raising it only means you'll wait longer for Lisp to give
up on trying to connect to a server.  Also, any temporary slowdowns in
existing connections may take longer to speed back up if Lisp has cranked
the round trip estimate needlessly high, but I suspect this effect is
minor.

The units are milliseconds.

	Bill