Path: utzoo!utgpu!water!watmath!clyde!rutgers!sunybcs!bingvaxu!leah!uwmcsd1!ig!agate!ucbvax!OKEEFFE.BERKELEY.EDU!karels
From: karels@OKEEFFE.BERKELEY.EDU (Mike Karels)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: PSN 7 End-to-End question.
Message-ID: <8802041821.AA21574@okeeffe.Berkeley.EDU>
Date: 4 Feb 88 18:21:52 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 13

Out of curiosity, I just timed an ftp transfer through our 1822 IMP
connection (10AM PST, load average 2.5 on a VAX 11/785) and got 9.6Kbytes/s.
The same transfer through software loopback ran up to 68Kbytes/s (with more
variance due to process scheduling).

Note that even when timing TCP transfers on an idle ARPANET over short
hops, the round-trip time is higher than when using most local-area networks.
Depending on the ack strategy, the TCP transfer rate is limited to
something on the order of one window per round-trip time.  Thus, failure
to reach 56 kb/s through the ARPANET using TCP is not necessarily due
only to internal overhead.

		Mike