Measuring Bandwidth Utilization on Cisco Switch Ports

Yesterday I spoke at the third Net Optics Think Tank in Santa Clara, CA. During the event one of the Net Optics product managers asked me about measuring bandwidth utilization on switch ports. I did not have an answer for him... until I took a look at the latest Packet magazine. The Q305 (.pdf) edition features a tip from Aurelio DeSimone on p. 13 mentioning the show controllers utilization command.

If anyone knows of a similar set of information via SNMP, please let me know via a comment here.

Here is sample output:

Switch> show controllers utilization
Port       Receive Utilization  Transmit Utilization
Fa0/1              0                    0
Fa0/2              0                    0
...truncated...
Total Ports : 12
Switch Receive Bandwidth Percentage Utilization  : 0
Switch Transmit Bandwidth Percentage Utilization : 0
Switch Fabric Percentage Utilization : 0

This is just the sort of data I would like to see for SPAN ports. You can specify the SPAN port in your syntax (e.g., show controllers fastethernet0/1 utilization) to see how much traffic it is carrying to your sensor.

The current Packet issue also features excellent articles on new modularity features of Cisco IOS and an overview of 10 GB Ethernet and its seven (yes, seven) variants. (There appear to be more, actually.) That sort of information reminds me of my "second law of information technology," which is "complexity increases." The second law of IT is constantly fighting the second law of thermodynamics, which is "entropy increases."