djd@H.CS.CMU.EDU.UUCP (02/18/87)
Newsgroups: mod.protocols Subject: Summary of info about 802.6 Reply-To: djd@h.cs.cmu.edu (Daniel Duchamp) Distribution: net Keywords: 802.6 A few days ago, I asked for information about IEEE committee 802.6. This post gives a summary of what I've learned. Two earlier posts contain information that is entirely correct. They are repeated at the end of this article. I contacted Mr. Joe Mollenauer, who works for Computervision in Bedford, MA. He is a committee member. I forgot to ask if he is chairman. His phone is 617-275-4404. He said that the Burroughs proposal described below is now dead, and that the committee is considering FDDI (also described below), a proposal from Australia called QPSX, and broadband cable TV operating at low speeds. He said that the committee welcomes other proposals as well. QPSX is logically a linear bus bent into a physical ring. It operates at 140Mb. The touted advantages are a scheduling algorithm that can achieve very high utilization, and robustness: if the ring breaks, then reorganization takes place that moves the end of the logical bus to where the physical ring is broken. Hard copy of the various draft proposals can be obtained (in return for cash, of course) from Ms. Carol Baca who works at Alpha Graphics in Phoenix. Her number is 602-863-0999. -- Dan Duchamp In article <8702171930.AA10800@seismo.CSS.GOV>, devine@seismo.CSS.GOV@vianet.UUCP writes: >In article <MS.V3.18.ms6b.80020b28.liberty.sun.2158.0@andrew.cmu.edu>, ms6b#@ANDREW.CMU.EDU (Marvin Sirbu) writes: >> The 802.6 committee was considering a proposal from Burroughs for a fiber >> ring metropolitan area network that would run at around 50 Mbps. There >> is a writeup in the IEEE Journal of Selected Areas in Communications by >> Dan Sze from about January 1986 (the special issue on Fiber LANs). > >> It is my understanding that Burroughs has disbanded the group which had been >> pushing the 802.6 draft, and that the IEEE 802.6 committee is back to square >> one. I believe the FDDI standard is seen as solving many of the problems >> that 802.6 was intended to address. The balance are being solved by the >> draft proposals for a broadband ISDN now circulating within ANSI T1D1.1 > > Yes that is true. I worked on this project. The proposal put before >the 802.6 (Metropolitan Area Network group) was for a slotted ring for >data and real-time communication. The backbone portion ran at 50 Mbps; >slower workstation-connecting rings ran at 12.5 Mbps. Both used the same >type of data link frame but the slower rings had less frames. > > The BDA project was canceled when Burroughs was looking for cash to buy >Sperry (the feeling is that Burroughs headquarters short-sightedly regarded >the project as not fitting in with its current line of machine, and as a >result, was worth cutting even though the previous month's employee >magazine touted BDA as a bright star in Burroughs future...). > > FDDI is, at present, a solution in search of a problem. It does, however, >provide a standardizing influence for the next generation of backbone >networks and provides more bandwidth for those sites whose Hyperchannel >is swamped. I have read of several vendors promising to bring out a conformant >implementation in a year or two : Fibronics, Proteon. And rumors have it that >several other companies (DEC, IBM) are working on it too. ( For those who >haven't followed the development of FDDI, it is an ANSI standard 100 Mbps >network running over two fiber optic cables. One interesting feature is >its use of 4B/5B encoding instead of the Manchester encoding used in most >current networks.) > > I am unsure of the status of 802.6. I have heard that a new 802 >subgroup - 802.7 - is now handling the standardization of slotted ring. > >Bob Devine >Western Digital, Boulder Tech Ctr -- Name: Dan Duchamp Phone: 412-268-2580 Internet: djd@h.cs.cmu.edu Usenet: {seismo,decvax}!cmucspt!djd