Alarm Conﬁguration

NOTE

Alarm conditions which occur over the span of two timebase intervals will not be detected, even if the threshold is crossed within a period of time that is less than or equal to the deﬁned timebase interval. For example, if you set your timebase to 10 seconds and an alarm threshold to 50, an alarm will be generated if 50 of the speciﬁed events are detected within a speciﬁc 10-second interval deﬁned by the device. If, however, those 50 events occur in any 10-second time frame which straddles two device-deﬁned intervals — say, 25 in the last ﬁve seconds of one interval, and 25 in the ﬁrst ﬁve seconds of the following interval — that condition will not be detected, and no alarm will be generated. These conditions are most likely to occur when a large threshold is used with a short timebase interval.

The Alarm Type options at the top of the window represent the variables for which you can assign station-level alarm thresholds. To change the status or threshold for an alarm type, you must ﬁrst click on its option at the top of the window; threshold and status changes will be applied to the alarm type selected at the time the changes are made and to the stations as determined by the current setting in the Set Alarm For ﬁeld. You can set an alarm threshold for the following variables:

Line Errors	A line error indicates the presence of a coding violation
	between the starting and ending delimiters of data, a
	frame check sequence error, or a code violation in a
	token. These can be caused by power surges on the ring;
	they are counted, but initiate no other recovery
	procedures.
Internal Errors	An internal error is counted when a station recognizes a
	recoverable internal error in its own adapter (and may
	temporarily remove itself from the ring). A large number
	of internal errors indicates a station in marginal
	operating condition; possible problems include
	inoperable chipset, timers, or counters.
Burst Errors	A burst error occurs when ﬁve half-bits of Manchester-
	encoded data are received by a station without a phase
	change (a signal transition from 0 to 1 or from 1 to 0).
	This error is normal when stations enter or leave the ring
	without phantom current; however, it can also indicate a
	problem with the receiver on the reporting node, the
	transmitter on its NAUN, or the cabling or hub hardware
	between them. Burst errors will cause the active monitor
	to initiate the ring purge process.

Setting and Viewing Station Alarms

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