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: <8622@ucbvax.ARPA> Date: Fri, 28-Jun-85 20:22:48 EDT Article-I.D.: ucbvax.8622 Posted: Fri Jun 28 20:22:48 1985 Date-Received: Sat, 29-Jun-85 03:49:51 EDT Sender: daemon@ucbvax.ARPA Organization: University of California at Berkeley Lines: 23 From: ihnp4!ihu1e!jee@BERKELEY The protocol on the Hyperchannel is best described as a CSMA/CP where CP is collision prevention. This roughly equates to a p-persistenc CSMA except it is prioritized. What all this means is that it is CSMA when it is planning to transmit. All adapters recognize when a transmission is happening. If they have to transmit each waits a different time (the backoff algorithm) which is preselected (the priority). It is true that prior to transmission of the actually date there is a control information exchange with the destination adapter. It is a simple way of making sure the channel is clear prior to transmission (i.e collision occurring after transmission begins) and the time is only equal to the round trip time. This control information allowys them to do transmit very large packets (much more than 4kbytes). In fact their protocol is similar to the proposed ANS X3T9.5 proposed standard for high speed local networks. I would suggest you contact Network Systems Corporation in Minneapolis, Minnesota directly for some introductory information which goes into much more detail.