devine@seismo.CSS.GOV@vianet.UUCP (02/17/87)
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