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Determine Utilization


We're going to be upgrading our peering connectivity in the near future, and I'd like to be able to find out 1) how much traffic my router is currently handling (pps mbps) 2) if my current router will handle the upgrade.

I currently have a 3660 with 1 FE, 1E and about 20 Serial T1 interfaces. Our main internet pipe is a 10mbps internet connection. We are looking to go to 100mpbs for our main pipe. If my 3660 won't handle it, what would you recommend?

Thanks. Craig


Re: Determine Utilization

would first recommend to start getting SNMP traffic statistics and get a baseline of your 20 serial lines network traffic average % utilization, including your fe interfaces coming into the LAN.

if you do not have any SNMP monitoring software here are some you could try:

Variety of Cisco's network management tools


Also MRTG for your WAN traffic monitoring (Freeware)

Also retrieve information on the 3660 CPU utilization during production hours, when the router is most busy.

issue this command:

"show process cpu history" would at least give you three days worth of cpu average utilization statistics.

based on gathering the above information on network traffic and cpu load you could plan accordingly.



Community Member

Re: Determine Utilization

Ok, so theres no magic command to show total packet switching stats ,etc?

I have snmp setup on my network. My T1's run at about 20% utilization on average. Most at about 300k. My FE interface is VLAN'd out to my LAN and to the Internet. The average utilization on that is at 7-8mbps. I have a Ethernet interface for a Metro network that runs at about 2mbps.

The average CPU utilization is at 15%, though we have spikes because of the bgp scanner process I believe.

Whats the best way to determine how much of my current router I'm using, and how much more room I have to push it?


Also, my monitoring is reporting some buffer misses. Are these normal, if not what could be causing them?

Re: Determine Utilization

refer on how buffers functions and related commands.

Troubleshooting buffer leaks

Buffer tuning on Cisco routers

from what you are indicating the router is not maxing out in processing data, although buffer misses may present some concern look at the links above.

%15 average CPU utilization for a router with 20 T1s is outstanding.

again to determine how much the router is using is based on gathering at least a week long if not a month of traffic stats and router load and do the math based on that info,



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