Path: utzoo!attcan!uunet!samsung!sdd.hp.com!ucsd!ucbvax!mk6vms.nwscc.sea06.navy.mil!mcrae
From: mcrae@mk6vms.nwscc.sea06.navy.mil ("Murl McRae")
Newsgroups: comp.protocols.tcp-ip
Subject: RE: WIN/TCP Window Size
Message-ID: <9007212227.AA12224@ucbvax.Berkeley.EDU>
Date: 19 Jul 90 17:17:00 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 22

As requested by BILLW@mathom.cisco.com on 19-JUL-1990 08:31, here is
more information on my WIN/TCP window size question:
 
    The reason I wanted to change the window size was to see if that
would improve our Internet performance.  We have a very slow Internet link.
The average roundtrip time is around 1.5 seconds.  Our FTP transfer rate is
only about 9.6K bits/sec.  With the long roundtrip time we thought a larger
window might help increase FTP throughput so we wanted to change the window
(both send and receive) and run some tests.
     Since I posted the orginal message I have found out how to change the
window sizes.  I changed the sizes from 4096 to 8192 and we tried a few 
transfers.  The results were inconclusive.  I don't think the performance
changed.  I did notice that all of the other hosts in the test had receive
windows around 4K (obviously I am rather green at this stuff), so if we did
get any improvement it would be in one direction only.  So it looks to me
like I ought to return the window sizes to 4096 and leave them alone.
    Any other sugguestions on improving performance on a slow link would
be appreciated.  Our current link into MILNET is via sattelite.  We are
working on getting a land line, but that may take a while.  Thanks.
 
Murl McRae                                 Naval Weapons Support Center
                                           Crane, Indiana