RuggedCom RS400 manual Rmon Alarms, Utilization

Ethernet Statistics

2. Packet has invalid CRC.

Collisions

Synopsis: 0 to 4294967295

The number of received packets for which Collision Event has been detected.

Utilization

Synopsis: 0 to 4294967295

The best estimate of the mean physical layer network utilization on this interface during this sampling interval (hundredths of percent)

4.4.3 RMON Alarms

RMON Alarms table configures the switch to examine the state of a specific statistic variable.

The record of this table contains an upper and a lower threshold for legal values of the statistic in a given interval. This provides the ability to detect events occurring more quickly than a specified maximum rate or less quickly than a specified minimum rate.

When a statistic value’s rate of change exceeds its limits an internal alarm of INFO level is always generated. Internal alarms can be viewed using the Diagnostics menu, View Alarms command.

Additionally, a statistic threshold crossing can result in further activity. The RMON Alarm record can be configured to point to a particular RMON Event Record, which can generate an SNMP trap, an entry in the switch’s event log or both. The RMON Event Record can “steer” alarms towards different users defined in SNMP Users table.

The alarm record can point to a different event record for each of the thresholds, so combinations such as “trap on rising threshold” or “trap on rising threshold, log and trap on falling threshold” are possible.

If the very first statistic measurement (after switch reset or after the record is created) immediately exceeds the configured thresholds decision, it is upon configuration whether or not to generate an alarm.

The ability to configure upper and lower thresholds on the value of a measured statistic provide for the ability to add hysteresis to the alarm generation process.

If the value of the measured statistic over time is compared to a single threshold, alarms will be generated each time the statistic crosses the threshold. If the statistic’s value fluctuates around the threshold, an alarm can generated every measurement period. Programming different upper and lower thresholds eliminate spurious alarms. The statistic value must “travel” between the thresholds before alarms can be generated.

The following figure illustrates the very different patterns of alarm generation resulting from a statistic sample and the same sample with hysteresis applied.

RS400 125 ROS™ v3.5