BW Measuring

[nandurisrini]

Dear Friends,

Can any one let me Know how to Caliculate the BW based on the reading from sh inter ser output from 5 minute i/p and o/p readings. will this reflect the Through put or any other parameter.

Rgds

Srini

[craigking]

Do you mean bandwidth, or bandwidth utilization? To determine the bandwidth of a particular circuit, you need to talk to your WAN carrier or check your documentation. To determine the bandwidth utilization, try this:

To figure out what the utilization rate is, divide each number by the speed of the circuit (e.g. a full T1 would be 1,544,000 bits, 128K=128,000 bits, and so on). Keep in mind that WAN circuits are full duplex, so a full T1 can support up to 1.544 Mbits in each direction simultaneously. Also remember that these stats are always in Mb (Mega*BITS*). If you want to know MB (Mega*BYTES*) then you need to divide everything by 8.

E.g. Full T1: Inbound average = 645,000 = (645,000/1,544,000)=41.7% Utilization.

Frac T1 (256Kb) Inbound Average = 58,500 bits = (58,500/256,000)=22.8% Utilization.

Take a look at MRTG if you want to automate this (and produce nice little graphs too!).

HTH,

CK

[Frederic Vanderbecq]

When using the show interface output, the '5 minute input rate' and the '5 minute output rate' represent the average rate measured over the last 5 minutes. If you need more precise measurement, you can decrease the average time by using the interface config command: load-interval and put to 30 seconds.

The other way to proceed is to take snapshots of the input and output byte counters at regular intervals and calculate the average in that way.

Though, both measurements will only give you averages.