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Conference 7.286::fddi

Title:FDDI - The Next Generation
Moderator:NETCAD::STEFANI
Created:Thu Apr 27 1989
Last Modified:Thu Jun 05 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:2259
Total number of notes:8590

97.0. "Speed Upgrade? How fast can it go?" by HPSRAD::COUGHLAN (Tom Coughlan, DTN 297-5407) Tue Jul 31 1990 14:41

    "The FDDI has also been designed for future speed upgrades.  It is
    contrasted with other standards that have inherent limitations in
    their protocols or access mechanisms.  By using the FDDI standard,
    the limitations that severely restrict speed upgrades should be
    decreased or eliminated."

			- from an article in "Computer Design"
			  by Sunil P. Joshi, 1985

Unfortunately, this claim is not substantiated in the article (and it is an
old article, anyway).  Is there any truth to it?  Is FDDI especially 
well-suited for "speed upgrades"?  Is anyone working on it?  

Presumably, the advantage of doing a speed upgrade on a LAN interconnect
is that the engineering investment would be less than if we started a new 
interconnect from scratch.  There is also the appealing prospect that
"everyone", from engineering to the customer, doesn't have to learn the
idiosyncrasies of a new interconnect.  
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97.1KONING::KONINGNI1D @FN42eqTue Jul 31 1990 18:2514
A 98% accurate answer would be "that's nonsense".

However, it is true that in many places the available fiber bandwidth is
greater than that used by FDDI.  This is true for short runs of multimode
fiber, and in certain cases (I'm not sure of the details) for single mode
fiber.

So when a hypothetical faster future LAN comes along, you might be able to
re-use SOME of your fiber cable.  You won't be able to re-use long multi-mode
runs, though, and obviously none of the active components will work.

So, for all practical purposes, the article is wrong.

	paul