1-Nov-81 22:38:30-PST,7374;000000000001 Mail-from: ARPANET host BRL rcvd at 1-Nov-81 2238-PST Date: 1 Nov 81 23:18:56-EDT (Sun) From: Mike Muuss To: tcp-ip at Brl Subject: TCP-IP Digest, Vol 1 #5 TCP/IP Digest Sunday, 1 November 1981 Volume 1 : Issue 5 Today's Topics: Solicitation for More Contributions More on BBN TCP for TOPS-20 Z8000 based TCP and IP Front End Machine ---------------------------------------------------------------------- From: Mike Muuss Reply-to: tcp-ip@brl Subject: More Contributions? Nearly a week has passed since the last issue, so I am publishing the three letters that have arrived in the interim . Considering the size of the mailing list, I can hardly immagine that we have heard from everybody who is working on networking implementations. C'mon! Lets hear from everybody. Cheers, -Mike ------------------------------ Date: 27 Oct 1981 1810-EST From: Jonathan Alan Solomon Subject: List maintainence You can announce [Rutgers]MAIL.TXT as an archive point if you like. ------------------------------ Date: 26 Oct 1981 0013-PST From: Mark Crispin Postal-Address: 725 Mariposa Ave. #103; Mountain View, CA 94041 Phone: (415) 497-1407 (Stanford); (415) 968-1052 (residence) Subject: Re: TCP-IP Digest, Vol 1 #4 I'd like to answer a few confusions about my position regarding the TOPS-20 implementation of TCP available from BBN. I am not, nor have I ever been, opposed to the TCP protocol. I was very impressed with the work done at the DoD Protocol Standards conference a year ago. I've been urging the managers of the Stanford local network effort to adopt TCP/IP as the local network protocol for the past two years now. It is the software that is presently available for TOPS-20 that I find distasteful. I have had some preliminary discussions with various people at DEC about this issue, and I have determined that they are addressing at least some of the objections. If the product DEC releases is less than what we would like, it is because of their rush to meet the deadline. It's a safe assumption that there is no way that DEC can possibly have a rewritten TCP implementation for TOPS-20 out in the field by the deadline date. I believe that DEC is doing its best. DEC's customers are probably best off encouraging the current project but being firm in stating that we must have a rewrite which addresses the performance problems of BBN's TCP. So far as the comments on how to "help/force people [to] implement TCP/IP" go: (1) There are those of us who would feel that not being able to reach our systems from a TIP is a feature, and not a problem at all! Entirely too many high school kids abuse the network from TIPs. (2) "Getting the mail through" can be accomplished by other means than implementing TCP. (3) Services only accessible via TCP/IP are a good reason for implementing TCP/IP. The example given was not a good one, but I can see other valuable resources being TCP/IP only. I hope by the time such resources exist there will be a better implementation of TCP/IP available. (4) The last point is patently ridiculous. US mail existed before electronic mail, and is still a commonly used method for communication between Investigators and their Sponsors. The whole tone of "forcing" is itself inane. The intent of my message was to discuss getting things moving towards solving the software situation, not to create an anti-TCP/IP lobby. The present TCP/IP software for TOPS-20 is unpalatable for most sites; if "forced" to implement TCP/IP on our systems we will probably have to write the software ourselves. Of course that would keep us from completing the projects our Network Sponsors are supporting us to do... -- Mark -- ------------------------------ Date: Mon, 26 Oct 1981 2236-EST From: steve at MITRE Subject: Z8000 TCP and IP Mike, I have been watching your digest with great interest. We have produced a micro-based TCP/IP here at MITRE which your readers may find useful. We have been involved in a series of projects whose focus was to make network access (both local and long haul) as straightforward as using common computer peripherals. The idea was that just as hardware controllers handle the particulars of a disk cylinder centerline or an end of tape sensor, some of the new microprocessors, in our case the Zilog Z8000, should make it possible to construct a "network controller" to handle the par- ticulars of packet ordering and flow control. To a large extent we have succeeded with a TCP/IP network controller supported by a Z8000 microprocessor box. The box is currently interfaced to our UNIX system via a UMC-Z80. It is accessed from the users point of view as a set of I/O like management calls (open, close, read, write, and special) which are transported via a network access protocol to the outboard box. The box has 64K bytes of Ram, 32K bytes of Rom, a Z8002 micro, and a serial Usart (880K BPS max). All of the software was written in C using a locally brewed version of the portable C compiler. The interesting aspect of the box is that it inter- faces as easily to a local network (in our case a the MITRE RF cable backbone) as it does to the ARPA network. Other than dif- ferent round trip delays, host user-level software sees no dis- tinction between the two networks. The long haul metamorphosis involves a new device driver in the Z8000 and the addition of an ACC 1822 hardware interface (yes, ACC makes one). The resulting set of building blocks allows us to interface a host, a terminal concentrator version and other units to a local net and have a gateway to the arpanet. While a custom protocol would be faster, we believe that the longer term interoperability of TCP/IP will be well worth some short term overhead. The performance even with TCP/IP isn't that bad in that we have measured two user processes talking via TCP/IP over the cable at 350K BPS. We have measured rates as high at 450K BPS when user I/O buffer sizes are set at 8K bytes per I/O. The Internet Protocol contains our lowest level of addressing. This allows us to address local units in the same way we address remote units two or three networks away. We have been experimenting with a version of TCP/IP which allows the optional specification of some TCP and IP mechanisms. The basic conclusion is that cable signalling rates are so fast that the effect of 300 bit TCP/IP headers has negligible impact on perfor- mance. Our work this year involves constructing a new version 10M BPS controller with multi-microprocessor capabilities. We believe the resulting effective TCP/IP communications rates should be well above 1M BPS and that the multi-microprocessor capabilities should make for an interesting distributed process- ing base. There a couple of reports available if people are in- terested. Regards Steve Holmgren END OF TCP-IP DIGEST ********************