About RMON History and Statistics

The RMON history and statistics features allow you to collect data about packets transmitted over Ethernet interfaces. For example, you can collect data such as the following:

  • Total number of packets transmitted

  • Broadcast packets transmitted

  • Multicast packets transmitted

  • Packets with CRC alignment errors

This kind of information is useful for maintaining optimum operation of the VNswitch and for troubleshooting problems.

The RMON history feature collects information on packets transmitted during sampling periods that you define (for example, every 5 minutes). You can use the data collected to compare packet behavior over a period of time.

The RMON statistics feature provides information on the total of various types of packets transmitted since the switch was started. For example, the statistics feature provides the total number of broadcast packets transmitted on an interface since the switch was started.

Configuring Tables and Displaying Information

You configure the RMON History and Statistics features by setting up rows in the history and statistics tables. The tables define parameters such as the interface for which data is collected, the interval for which data collection is to occur, and so forth. Once the control tables are set up, RMON can begin to collect and display information. RMON information is displayed in history and statistics data tables.

Note: By default, every interface on the device has two entries defined in the history control table.  One entry specifies a control interval of 30 seconds, which allows for the detection of sudden changes. The other specfies a control interval of 30 minutes, which allows for steady-state behavior of the interface.