Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!ames!pasteur!ucbvax!VAX.FTP.COM!jbvb
From: jbvb@VAX.FTP.COM (James Van Bokkelen)
Newsgroups: comp.protocols.tcp-ip.ibmpc
Subject: Re: Fast file transfer to PCs
Message-ID: <8803031916.AA00377@vax.ftp.com>
Date: 3 Mar 88 19:16:35 GMT
References: <2026@ho95e.ATT.COM>
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 15

On an 8Mhz AT, with Ethernet, we can get 1.5 megabits/sec out of our TCP
quite predictably (of course, this requires a fast interface and adaptive
retransmits on the sending end).  Faster processors increase our TCP speed,
because most of the computes are used up copying packets and checksumming
them.

UDP would go faster (provided you disable the data checksum, which is not
normally an option with our UDP), but you'd have to write your own protocol
to guarantee reliable delivery & retransmission, which might burn up all the
speed you gain.  I have heard it said that the Microchannel is somewhat faster
with at least two interfaces I've heard about, but on the order of 10%,
nothing spectacular.  I don't know if the cards in question had byte-wide
memory on the bus, or word-wide.

James VanBokkelen
FTP Software Inc.