Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!uakari.primate.wisc.edu!aplcen!aplcomm!uunet!edi386!eddjp
From: eddjp@edi386.UUCP ( Dewey Paciaffi )
Newsgroups: comp.protocols.tcp-ip
Subject: TCP Throughput over E-net
Message-ID: <167@edi386.UUCP>
Date: 27 Jun 91 14:42:46 GMT
Organization: J.M. Huber Corp. Edison, NJ
Lines: 34

I have a question regarding TCP throughput on Ethernet, and what affects
it on a local network. I have 3 systems, two Sparc2s and an RS6000. I'll
call them A, B, and C :

	A - Newly installed Sparc, SunOs 4.1.1
	B - 6 month old Production Sparc 4.1.1
	C - Newly installed RS/6000 AIX 3.1.5

When I transfer a 1.7 MB binary file between systems, the results are
inconsistent between systems when I change the direction of the data flow.
There is also an inconsistency from machine to machine. The throughputs are:

	A -> B     850 KB
	A -> C     550 KB
	B -> A     270 KB
	B -> C     500 KB
	C -> A     200 KB
	C -> B     270 KB

All machines are idle and I was the only user during the tests. I used
rlogin to get from machine to machine, and used ftp binary transfers.

Could the flow direction impact the throughput this greatly? I would 
normally attribute this to hardware and/or TCP implementation differences,
but two of the machines are identical, and they all transfer 500 KB or
greater to at least one other machine in at least one direction.

Of course, I'd like them all to transfer at 850 KB to all machines in all
directions :-). Is there something I've missed or something I should look
at in my set-up here ?

Thanks for any insight...
-- 
Dewey Paciaffi           ...!uunet!edi386!eddjp