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Monitor Swith port utilization trend !!!

Does anyone know the procedure in using MRTG to monitor specific switch port utilization trend since MRTG can keep long trend instead of online monitoring.!! I know that some MIBs must be know in configuration, right?


Re: Monitor Swith port utilization trend !!!

I am using it on NT, but you can install it on unix as well.

Here is the link:


1. install perl on your monitoring station.

2. Install mrtg on your station

3. configure the router/switch/pix to allow snmp from that station

4. configure a script file (called mrtg.cfg) that contains the MIBs you want to grab.


### Interface 2 >> Descr: 'FastEthernet0/1' | Name: 'Fa0/1' | Ip: '' | Eth: '00-07-ec-05-8f-01' ###

Target[]: 2:test@

SetEnv[]: MRTG_INT_IP="" MRTG_INT_DESCR="FastEthernet0/1"

MaxBytes[]: 12500000

Title[]: Traffic Analysis for 2 -- Switch2


Traffic Analysis for 2 -- Switch2

System: Switch2 in
ifType: ethernetCsmacd (6)
ifName: Fa0/1
Max Speed: 100 Mbits/s

WithPeak[]: ym

Options[]: bits

5. run the script from DOS using "perl mrtg mrtg.cfg" command.

For each event (eg CPU, mem, errors etc) you want to monitor you need to know the MIB (mrtg has some built in MIBs).

Very easy to set up, can do it in 30 minutes.

Hope that helps.


Community Member

Re: Monitor Swith port utilization trend !!!

Dear Steve,

Thank you for your kindly advice, but something that make me confuse is that

1) where do i input the MIBs value??

2) is it necessary to use Cisco propertiary MIBs??

and do u have more detail or sample configuration for this, Thanks!

Re: Monitor Swith port utilization trend !!!

1) MRTG by default will grab traffic stats (in/out) from your interfaces if you use the config I posted first. If you want different stats you enter MIBs as shown here:

# Router CPU load %


RouterUptime[cpu.1]: test@

MaxBytes[cpu.1]: 100

Title[cpu.1]: CPU LOAD


CPU Load %

Unscaled[cpu.1]: ymwd

ShortLegend[cpu.1]: %

XSize[cpu.1]: 380

YSize[cpu.1]: 100

YLegend[cpu.1]: CPU Utilization

Legend1[cpu.1]: CPU Utilization in % (Load)

Legend2[cpu.1]: CPU Utilization in % (Load)




LegendO[cpu.1]:  Usage

Options[cpu.1]: gauge

WithPeak[cpu.1]: ym

This will grab CPU stats from a router. Notive second line (target...), that's where you enter the community string, IP and MIB.

2) You can use any MIB that is recognized by the device. So my cisco router recognizes cisco specific MIBs and industry standard MIBs.

If there is a MIB, MRTG can grab it. But remember the device must understand the MIB to send the trap.

If you would like I can email you an example of a mrtg.cfg file (it's too big to post here) that shows memory, cpu, traffic and input errors from a cisco pix, router and switch.


Community Member

Re: Monitor Swith port utilization trend !!!

Dear Steve,

Actually, i want to monitor the utilization trends of some switch ports on a Catalyst 3548XL. My network configuration briefly describe as follow:

1) Two Catalyst 5500 running HSRP with 20 vlans loadsharing between 2 catalyst

2) Trunking to Distributed layer Catalyst 3548 and 3524 ( Server farm location)

3) Access layer with numbers of cat2924XL (user's workstation)

I would be grateful if u can send me an configuration file about a switch

Thank you for your help!!


Community Member

Re: Monitor Swith port utilization trend !!!


sorry, missing email address in previous message!! You can mail me at

Thks a lot!


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