Saturday, May 30, 2009

Configuring RMON Support

I didn’t found a document that describes a RMON feature in the order that it need to be configured so here is the right way to configure it:

 

RMON – is used to create event driven SNMP traps based on MIB’s that a Cisco device supports. RMON is made up of two sections, the first being an event and the second the alarm. Alarms are what occur on the router i.e. an increase/decrease in a MIB value. An RMON alarm is defined by issuing the rmon alarm global configuration command, and tracks the value of a MIB based on the delta (relative change) of the variable, or the absolute change of the variable. RMON can be used to track interface utilization. [Stephen Bowes] The main commands are rmon alarm... & rmon event.., verification involves show rmon alarms & sh rmon events.

 

For example we would like to configure a log description “interface f0/0 queue is full” when the queue rising to 75% and “interface f0/0 queue is ok” when queue is decreasing for 40% load. The MIB that we will query is ifEntry.20.

 

1) First we need to enable SNMP on the router:

 

R8>en

R8#conf t

Enter configuration commands, one per line.  End with CNTL/Z.

R8(config)#snmp-server enable traps

R8(config)#end

R8#

 

Following that all traps will appear on the router configuration.

 

2) We will check what is the MIB number on the interface router need to query:

 

R8#show snmp mib ifmib ifindex f0/0   

FastEthernet0/0: Ifindex = 2

R8#

 

3) Then we will make number “2” that identifies the MIB permanent.

 

R8(config)#snmp-server ifindex persist

 

4) Configure the destination for the logs:

 

R8(config)#logging on

R8(config)#logging buffered

R8(config)#logging monitor critical

 

5) Configuration of RMON event (name configuration for the alarm):

 

R8(config)#rmon event 1 log description "interface f0/0 queue full"

R8(config)#rmon event 2 log description "interface f0/0 queue ok"

 

6) Configuration of RMON alarm (trigger configuration):

 

R8(config)#rmon alarm 1 ifEntry.20.2 60 absolute rising-threshold 75 1 falling-threshold 40 2

 

The full configuration will be:

 

logging buffered 4096 debugging

logging monitor critical

!

snmp-server ifindex persist

snmp-server enable traps snmp authentication linkdown linkup coldstart warmstart

snmp-server enable traps tty

snmp-server enable traps casa

snmp-server enable traps gatekeeper

snmp-server enable traps xgcp

snmp-server enable traps director server-up server-down

snmp-server enable traps isdn call-information

snmp-server enable traps isdn layer2

snmp-server enable traps isdn chan-not-avail

snmp-server enable traps isdn ietf

snmp-server enable traps hsrp

snmp-server enable traps config

snmp-server enable traps entity

snmp-server enable traps config-copy

snmp-server enable traps envmon

snmp-server enable traps ds0-busyout

snmp-server enable traps ds1-loopback

snmp-server enable traps bgp

snmp-server enable traps pim neighbor-change rp-mapping-change invalid-pim-message

snmp-server enable traps ipmulticast

snmp-server enable traps msdp

snmp-server enable traps rsvp

snmp-server enable traps frame-relay

snmp-server enable traps frame-relay subif

snmp-server enable traps syslog

snmp-server enable traps rtr

snmp-server enable traps mpls ldp

snmp-server enable traps mpls traffic-eng

snmp-server enable traps mpls vpn

snmp-server enable traps cnpd

snmp-server enable traps stun

snmp-server enable traps dlsw

snmp-server enable traps bstun

snmp-server enable traps pppoe

snmp-server enable traps atm subif

snmp-server enable traps dial

snmp-server enable traps dsp card-status

snmp-server enable traps ipmobile

snmp-server enable traps vtp

snmp-server enable traps vsimaster

snmp-server enable traps voice poor-qov

snmp-server enable traps dnis

!

rmon event 1 log description "interface f0/0 queue full" owner config

rmon event 2 log description "interface f0/0 queue ok" owner config

rmon alarm 1 ifEntry.20.2 60 absolute rising-threshold 75 1 falling-threshold 40 2 owner config


R8#show rmon alarms 

Alarm 1 is active, owned by config

 Monitors ifEntry.20.2 every 60 second(s)

 Taking absolute samples, last value was 0

 Rising threshold is 75, assigned to event 1

 Falling threshold is 40, assigned to event 2

 On startup enable rising or falling alarm

   

R8#show rmon events 

Event 1 is active, owned by config

 Description is interface f0/0 queue full

 Event firing causes log,

 last event fired at  0y0w0d,00:00:00,

 Current uptime       0y0w0d,06:27:12

Event 2 is active, owned by config

 Description is interface f0/0 queue ok

 Event firing causes log,

 last event fired at  0y0w0d,06:23:46,

 Current uptime       0y0w0d,06:27:12

 Current log entries:

  index  uptime              description

  1      0y0w0d,06:23:46     interface f0/0 queue ok


R8#show rmon history 

History Control table is empty

      

R8#show rmon statistics 

Ethernet Statistics table is empty

R8#


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