Cabletron Systems SPECTRUM TRMMIM User Manual

Page 84

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Alarm Configuration

4-4

Setting and Viewing Ring Alarms

The Alarm Type list displays the variables available for alarms, the current status
of each alarm, and the current threshold setting. To change the status or threshold
for an alarm, you must first select it in this list. You can set an alarm threshold for
the following variables:

Ring Purges

The number of times the active monitor has purged the
ring since the network was created, or since the
TRMMIM was last reset. This includes the purge at the
end of the active monitor selection process; however, the
count is not reset when the active monitor changes.

Active Monitor

The number of times a duplicate active monitor has been

Participant

detected on the ring. When any station which considers

Errors

itself to be the active monitor receives a ring purge or
AMP (active monitor present) frame that it did not
transmit, it will become a standby monitor. If this process
leaves the ring without an active monitor (because both
active monitors have switched to standby mode), the
monitor contention process will begin.

Token Errors

The number of times the active monitor either does not
see a token circulating on the ring before its TVX (Timer,
Valid Transmission) timer expires (e.g., a Lost Frame
error has occurred), or sees a recirculating frame or
token. Each time a token error is noted, the active
monitor purges the ring and issues a new token.

Claim Token

The number of times a claim token has been released by a

Errors

station on the ring. A claim token is released when a
station detects that the active monitor is missing or
malfunctioning, or following a beaconing condition; the
issuing of a claim token initiates the monitor contention
process, through which a new active monitor will be
chosen.

Lost Frames

The number of times a station’s TRR (Timer, Return to
Repeat) timer expires before the frame it is transmitting
returns. This timer, which is set to 4.1 milliseconds,
ensures that each station returns to the data repeat state
after transmitting: retrieves its token, strips it of data,
and issues a new token. Lost frame errors will cause the
active monitor to initiate the ring purge process and issue
a new token; these errors are usually caused by stations
entering or leaving the ring while a frame is circulating
(since stations entering or leaving briefly throw the ring
out of sync).

Frame Count

The number of frames detected on the ring.

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