A Proactive alarm is made up of one or more issues, such as Downstream Power or Upstream Noise. An issue is triggered when a configured threshold is crossed, and an alarm is raised when the configured number of contiguous modems are affected by the issue. Generally, modems are considered contiguous if they are directly connected to each other on the network.
Each type of issue can be triggered when a threshold is crossed for one or more RF Parameters. For example, a Downstream Power issue is triggered when the downstream receive power (RF Parameter) is above or below the defined threshold range. In addition to CM issues on SC-QAM channels, issues on OFDM and OFDM/A channels also generate alarms and are reported.
An alarm's highest threshold crossing can also be measured by examining all cable modems, key performance indicators, and frequencies to arrive at a highest overall severity.
Some issue types can be triggered by only one RF Parameter, and others can be triggered by any of several RF Parameters. For example, a Downstream Noise issue can be triggered when downstream SNR drops below the configured threshold, and it can also be triggered when downstream MER drops below the configured threshold.
Each issue has one or more associated frequencies (channels). Similar issues are rolled up across frequencies.