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From: vjs@rhyolite.wpd.sgi.com (Vernon Schryver)
Newsgroups: comp.dcom.lans
Subject: Re: Info on FDDI SMT
Keywords: FDDI, SMT, X3T9.5
Message-ID: <97250@sgi.sgi.com>
Date: 14 Apr 91 03:45:33 GMT
References: <97028@sgi.sgi.com> <1991Apr11.221054.25188@leland.Stanford.EDU> <1991Apr12.233143.722@berlioz.nsc.com>
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Organization: Silicon Graphics, Inc., Mountain View, CA
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In article <1991Apr12.233143.722@berlioz.nsc.com>, my@falcon.nsc.com (Michael Yip) writes:
>  ...
> I am in the camp of saying "let SNMP or OSI manage things" ... but I don't
> shout "Enough changes and Done."  I think that we should have a minimum
> set of functions and extra (eg PMFs) should be just extra.  That way 
> people can get on implementing FDDI now and add extra later without breaking
> things.  ....
>                                 The earlier that we get SMT and FDDI out the
> door, the more popular FDDI will be ... or else we will miss the market
> window and FDDI will be yet another vapor_net.

> -- Mike Yip
>    my@berlioz.nsc.com
> PS:  BY the way, what do people think about FDDI-2??

I've been muttering for many years on a many subjects "any fool can add
features; the trick is in leaving them out."

PMF's etc would have been a keen idea 5 years ago, before SNMP, before the
market decide INTERnetwork management was possible and desirable.  At this
late date, it is strange to delay SMT to perfect a network management
scheme that only works on the local ring not even crossing bridges, to
believe that TCP is hard in these days of free 4.3BSD and KA9Q source and
dirt cheap MB RAMs and Mbit PROMS, to mandate a link layer management that
needs a transport with most of the machinery of UDP/IP (the worst case size
of some of the frames is >4500bytes).  It's as if some in X3T9.5 have
commercial death wishes.

Instead of delaying to elaborate and fix PMF's, X3T9.5 should have finished
SMT 3 years ago, and started a SMT2 with all of the bells and whistles.
In the interum we could have seen how NIF's etc. really work, to find what
fails in real life.  (I type this after having to come in Sat. night to
clean up after a power failure in a multi-building ring used by primary
source machines--two few optical bypasses can give you sausage--big surprise.)

The good news is that many customers and vendors are going ahead, treating
the current standard like the Ethernet Blue book of old, and building,
shipping, buying, and installing networks.


How are people planning to use FDDI2?  (That's an honest question; I wasn't
paying attention when it started.)
FDDI is theoretically 10x ethernet.  Any pair of cheap 1990 workstations
worth buying can staturate one ethernet (i.e. get around 1MByte/sec with
ttcp).  How are you going to have any useful bandwidth left in FDDI2 if you
reserve enough to do video?  Doesn't one video channel need >= 5MByte/sec?


Vernon Schryver,   vjs@sgi.com