Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.3 alpha 4/15/85; site ucbvax.ARPA Path: utzoo!watmath!clyde!burl!ulysses!ucbvax!tcp-ip From: tcp-ip@ucbvax.ARPA Newsgroups: fa.tcp-ip Subject: Re: TCP/IP on Hyperchannel Message-ID: <8283@ucbvax.ARPA> Date: Tue, 18-Jun-85 18:04:55 EDT Article-I.D.: ucbvax.8283 Posted: Tue Jun 18 18:04:55 1985 Date-Received: Thu, 20-Jun-85 20:14:11 EDT Sender: daemon@ucbvax.ARPA Organization: University of California at Berkeley Lines: 19 From: "J. Spencer Love" There is an implementation of TCP/IP via the Hyperchannel for Multics, which is used as an in-machine-room local area network between 4 Multics systems in the Pentagon. By setting the window size to 50000 and the packet size to 5000, we were able to get FTP rates on a single connection as high as 275,000 bits per second. These large buffers and packet sizes are not a problem for Multics, but we had to special case the window size for our multi-home test site, since many implementations on the ARPAnet do strange and bizarre things when given huge windows. (Reply to me if you want a somewhat more detailed description). Spitting data straight through the network we were only able to unload 800,000 bits per second (with no protocol). This is a tiny fraction of the raw bandwidth of the network. We blame the problem on the hardware interface design, which is amazingly brain damaged. Given this performance, I would recommend practically any other vendor who has an appropriate interface card for your machine; you'll spend a whole lot less money and get much better service.