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From: my@dtg.nsc.com (Michael Yip)
Newsgroups: comp.dcom.lans,comp.protocols.tcp-ip
Subject: Re: Token Ring frame sizes?  (FDDI also)
Summary: How many frames I can send?  FDDi and Token Ring?
Keywords: FDDI, Token Ring, Frames
Message-ID: <1379@cuckoo.nsc.com>
Date: 16 Aug 90 17:32:35 GMT
References: <38470004@hpindwa.HP.COM> <1990Aug15.213146.2836@ibmpa> <67003@sgi.sgi.com>
Reply-To: my@cuckoo.UUCP (Michael Yip)
Distribution: na, ba
Organization: National Semiconductor, Santa Clara
Lines: 20


I agree with Rob from Silicon Graphic.

One can hold the token for a very long time (Limited by T_Opr for
the particular station).  In our FDDI Lab in National Semiconductor,
I once tried to do the same experiment.  I specificed a very large
value of T_Req on every station, let the ring started.  When the ring
started, the FDDI token was rotating very very fast.  It rotated once
per T_Ring_Latency.  Then I started a station to transmit frames, not 
large ones but many many small or medium size frames.  That station had
so many frames to transmit until T_Opr expired and forced to release
the token and not transmitting.  The result?  The token rotated so slow
that I could count it myself by looking at Token Counter display on my 
program.  The conclusion ... yes, it is possible to hold the token for
a very long time.  If the station is capable to do so.  

-- Mike

PS: So Rob, can we go graceful insertion of a station into a FDDI
    concentrator by holding the token and let the station into the ring?