Remote Network Monitoring
December 2005 © Foundry Networks, Inc. B - 9
FESX424 Router(config)# rmon history 1 interface 1 buckets 10 interval 10 owner
nyc02
Syntax: rmon history <entry-number> interface [<slotnum>/]<portnum> buckets <number> interval <sampling-
interval> owner <text-string>
You can modify the sampling interval and the bucket (number of entries saved before overwrite) using the CLI. In
the above example, owner refers to the RMON station that will request the information.
NOTE: To review the control data entry for each port or interface, enter the show rmon history command.
Alarm (RMON Group 3)
Alarm is designed to monitor configured thresholds for any SNMP integer, time tick, gauge or counter MIB object.
Using the CLI, you can define what MIB objects are monitored, the type of thresholds that are monitored (falling,
rising or both), the value of those thresholds, and the sample type (absolute or delta).
An alarm event is reported each time that a threshold is exceeded. The alarm entry also indicates the action
(event) to be taken if the threshold be exceeded.
A sample CLI alarm entry and its syntax is shown below:
FESX424 Router(config)# rmon alarm 1 ifInOctets.6 10 delta rising-threshold 100 1
falling threshold 50 1 owner nyc02
Syntax: rmon alarm <entry-number> <MIB-object.interface-num> <sampling-time> <sample-type>
<threshold-type> <threshold-value> <event-number> <threshold-type> <threshold-value> <event-number>
owner <text-string>
Event (RMON Group 9)
There are two elements to the Event Group—the event control table and the event log table.
The event control table defines the action to be taken when an alarm is reported. Defined events can be found by
entering the CLI command, show event. The Event Log Table collects and stores reported events for retrieval by
an RMON application.
A sample entry and syntax of the event control table is shown below:
FESX424 Router(config)# rmon event 1 description ‘testing a longer string’ log-and-
trap public owner nyc02
Syntax: rmon event <event-entry> description <text-string> log | trap | log-and-trap owner <rmon-station>
sFlow
sFlow is a system for observing traffic flow patterns and quantities within and among a set of Layer 2 Switches and
Layer 3 Switches. To support sFlow, participating Layer 2 and Layer 3 devices:
• Sample packet flows
• Collect the packet headers from sampled packets and collect ingress-egress information on these packets
• Compose the collected information into flow sample messages
• Relay these messages to an external device known as a collector
Participating devices also relay byte and packet counter data (counter samples) for ports to the collector.
sFlow is described in RFC 3176, “InMon Corporation's sFlow: A Method for Monitoring Traffic in Switched and
Routed Networks”. Refer to this RFC to determine the contents of the sampled packet.
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