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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

1342.0. "CNS PC trace path test" by CSC32::PITT () Wed May 25 1994 03:34

    
    3000/400
    OSF v2.0
    
    Seeing an error that says only,
    
    FZA0 port in the halt state
    CNS PC trace path test.
    
    Only one other node in the ring shows the same error.
    
    Can someone point me to the doc where these error messages are
    described?
    
    thanks.

T.R Title User Personal
Name Date Lines

1342.1 KONING::KONING Paul Koning, B-16504 Wed May 25 1994 15:29 23

T.R	Title	User	Personal Name	Date	Lines
1342.1		KONING::KONING	Paul Koning, B-16504	`Wed May 25 1994 15:29`	23
	"PC Trace" is an FDDI standard mechanism that is used when the ring has been "stuck beaconing" for about 7 seconds. This is a sign that there is some hardware problem internal to a station. The PC Trace signal is propagated among the stations where the problem might be, and each is then required to disconnect and perform a selftest. The possible causes of this event are (a) you have a broken station, or (b) you have a station with a bug that causes PC Trace to be signalled incorrectly (Cisco boxes have been seen doing this). To sort it out, put an analyzer on the ring and look for beacons. If you see steady beacons for 7 seconds, then you have case (a), and the broken station is the station beaconing, the station containing the MAC upstream from that one, or one of the stations in between. All these get the PC Trace signal, and all should have done a selftest. (If they are Digital products, they will; if not, they may or may not do a selftest, though the standard clearly requires it.) If they did, then the fault should have been detected, and the station in question should have stayed off the ring. If you do NOT see "stuck beaconing" then you have case (b) and the answer is to try to get rid of the station that initiated the PC Trace. paul

"PC Trace" is an FDDI standard mechanism that is used when the ring has
been "stuck beaconing" for about 7 seconds.  This is a sign that there is
some hardware problem internal to a station.  The PC Trace signal is propagated
among the stations where the problem might be, and each is then required to
disconnect and perform a selftest. 

The possible causes of this event are (a) you have a broken station, or (b) you
have a station with a bug that causes PC Trace to be signalled incorrectly
(Cisco boxes have been seen doing this).

To sort it out, put an analyzer on the ring and look for beacons.  If you
see steady beacons for 7 seconds, then you have case (a), and the broken
station is the station beaconing, the station containing the MAC upstream
from that one, or one of the stations in between.  All these get the PC Trace
signal, and all should have done a selftest.  (If they are Digital products,
they will; if not, they may or may not do a selftest, though the standard
clearly requires it.)  If they did, then the fault should have been detected,
and the station in question should have stayed off the ring.

If you do NOT see "stuck beaconing" then you have case (b) and the answer is to
try to get rid of the station that initiated the PC Trace.  

	paul