Saturday, April 18, 2009

RMON - Remote Monitoring

Before i detail the lab scenario a brief overview of RMON:

RMON is an IETF standard developed to enable network management stats to be gathered from remote sites without the overhead of SNMP constantly polling. When RMON is configured it gathers info and passes it back to management nodes. RMON is designed to work in conjunction with SNMP. Typically SNMP is enabled alongside RMON for an effective solution.

Lab scenario:
i) configure R1 to generate an SNMP trap whenever the output queue length (ifEntry.21.2) of its Serial0/0 interface exceeds 250 packets.
ii) This MIB value should be sampled every 30 seconds.
iii) When there are more than 250 packets in the output queue R1 should generate the message “WARNING: S1/0 Congested”.
iv) When the value falls back to 50 R1 should generate the message “INFO: S1/0returned to normal utilization”.
v) R1 should send SNMP traps to is with the community string to be RICHTRAP

With RMON first configure the events and then configure the associated alarms

rmon alarm 1 ifEntry.21.2 60 absolute rising-threshold 250 1 falling-threshold 50 2
rmon event 1 trap IETRAP description "WARNING: S1/0 Congested"
rmon event 2 trap IETRAP description "INFO S1/0 returned to normal utilization"

Then configure the SNMP traps.

snmp-server host IETRAP
snmp-server enable traps

As taken from the cisco doc:
For a host to receive notifications, at least one snmp-server enable command and the snmp-server host command for that host must be enabled.

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