Configuring RMON

This chapter contains the following sections:

Information About RMON

RMON is an Internet Engineering Task Force (IETF) standard monitoring specification that allows various network agents and console systems to exchange network monitoring data. The Cisco NX-OS supports RMON alarms, events and logs to monitor Cisco Nexus 3000 Series switches

An RMON alarm monitors a specific management information base (MIB) object for a specified interval, triggers an alarm at a specified threshold value (threshold), and resets the alarm at another threshold value. You can use alarms with RMON events to generate a log entry or an SNMP notification when the RMON alarm triggers.

RMON is disabled by default and no events or alarms are configured in Cisco Nexus 3000 Series. You can configure your RMON alarms and events by using the CLI or an SNMP-compatible network management station

RMON Alarms

You can set an alarm on any MIB object that resolves into an SNMP INTEGER type. The specified object must be an existing SNMP MIB object in standard dot notation (for example, 1.3.6.1.2.1.2.2.1.17 represents ifOutOctets.17).

When you create an alarm, you specify the following parameters:

  • MIB object to monitor

  • Sampling interval—The interval that the Cisco Nexus 3000 Series switch uses to collect a sample value of the MIB object.

  • The sample type—Absolute samples take the current snapshot of the MIB object value. Delta samples take two consecutive samples and calculate the difference between them.

  • Rising threshold—The value at which the Cisco Nexus 3000 Series switch triggers a rising alarm or resets a falling alarm.

  • Falling threshold—The value at which the Cisco Nexus 3000 Series switch triggers a falling alarm or resets a rising alarm.

  • Events—The action that the Cisco Nexus 3000 Series switch takes when an alarm (rising or falling) triggers.


Note

Use the hcalarms option to set an alarm on a 64-bit integer MIB object.

For example, you can set a delta type rising alarm on an error counter MIB object. If the error counter delta exceeds this value, you can trigger an event that sends an SNMP notification and logs the rising alarm event. This rising alarm will not occur again until the delta sample for the error counter drops below the falling threshold.


Note

The falling threshold must be less than the rising threshold.

RMON Events

You can associate a particular event to each RMON alarm. RMON supports the following event types:

  • SNMP notification—Sends an SNMP risingAlarm or fallingAlarm notification when the associated alarm triggers.

  • Log—Adds an entry in the RMON log table when the associated alarm triggers.

  • Both—Sends an SNMP notification and adds an entry in the RMON log table when the associated alarm triggers.

You can specify a different even for a falling alarm and a rising alarm.

Configuration Guidelines and Limitations for RMON

RMON has the following configuration guidelines and limitations:

  • You must configure an SNMP user an notification receiver to use the SNMP notification event type.

  • You can only configure an RMON alarm on a MIB object that resolves to an integer.

Configuring RMON

Configuring RMON Alarms

You can configure RMON alarms on any integer-based SNMP MIB object.

You can optionally specify the following parameters:

  • The event-number to trigger if the rising or falling threshold exceeds the specified limit.

  • The owner of the alarm.

Ensure you have configured an SNMP user and enabled SNMP notifications.

Procedure
     Command or ActionPurpose
    Step 1 switch# configure terminal
     

    Enters configuration mode.

     
    Step 2 switch(config)# rmon alarm index mib-object sample-interval {absolute | delta} rising-threshold value [event-index] falling-threshold value [event-index] [owner name]
     

    Creates an RMON alarm. The value range is from -2147483647 to 2147483647. The owner name can be any alphanumeric string.

     
    Step 3 switch(config)# rmon hcalarm index mib-object sample-interval {absolute | delta} rising-threshold-high value rising-threshold-low value [event-index] falling-threshold-high value falling-threshold-low value [event-index] [owner name] [storagetype type]
     

    Creates an RMON high-capacity alarm. The value range is from -2147483647 to 2147483647. The owner name can be any alphanumeric string.

    The storage type range is from 1 to 5.

     
    Step 4 switch# show rmon {alarms | hcalarms}
          		(Optional)

    Displays information about RMON alarms or high-capacity alarms.

     
    Step 5 switch# copy running-config startup-config
          		(Optional)

    Saves this configuration change.

     

    The following example shows how to configure RMON alarms: 

    switch# configure terminal

    switch(config)# rmon alarm 1 1.3.6.1.2.1.2.2.1.17.83886080 5 delta rising-threshold 5 1 falling-threshold 0 owner test

    switch(config)# exit

    switch# show rmon alarms

    Alarm 1 is active, owned by test
     Monitors 1.3.6.1.2.1.2.2.1.17.83886080 every 5 second(s)
     Taking delta samples, last value was 0
     Rising threshold is 5, assigned to event 1
     Falling threshold is 0, assigned to event 0
     On startup enable rising or falling alarm

    Configuring RMON Events

    You can configure RMON events to associate with RMON alarms. You can reuse the same event with multiple RMON alarms.

    Ensure you have configured an SNMP user and enabled SNMP notifications.

    Procedure
       Command or ActionPurpose
      Step 1 switch# configure terminal
       

      Enters configuration mode.

       
      Step 2 switch(config)# rmon event index [description string] [log] [trap] [owner name]
       

      Configures an RMON event. The description string and owner name can be any alphanumeric string.

       
      Step 3 switch(config)# show rmon {alarms | hcalarms}
              		(Optional)

      Displays information about RMON alarms or high-capacity alarms.

       
      Step 4 switch# copy running-config startup-config
              		(Optional)

      Saves this configuration change.

       

      Verifying RMON Configuration

      To display RMON configuration information, perform one of the following tasks:

      Command

      Purpose

      switch# show rmon alarms

      Displays information about RMON alarms.

      switch# show rmon events

      Displays information about RMON events.

      switch# show rmon hcalarms

      Displays information about RMON hcalarms.

      switch# show rmon logs

      Displays information about RMON logs.

      Default RMON Settings

      The following table lists the default settings for RMON parameters.

      Table 1  Default RMON Parameters

      Parameters

      Default

      Alarms

      None configured.

      Events

      None configured.