Manually calculating bandwidth usage 1

[tammyrus]

I need to calculate the bandwidth usage from router A to router B and any given time. I cannot use software. I was told that this is possible by using the numbers from the input rate and output rate on the interface. Anyone know anything about this?

 

[Belushi]

If you perform the "show interface (interface type/number)" command on any interface it will give you a laundry list of information. Among that list is the receive laod (rxload) and transmit load (txload). These loads are measured as a fraction where the value is over 255. For example rxload = 25/255. What this means is that approximately 1/10 or 25/255 of the circuit is being used during the time sampling period. The time sampling period is normally 5 minutes by default and is also displayed with the show interface command. Also, the bandwidth is diaplyed with this command. Apply that percentage of bandwidth used that I explained before to the configured bandwidth of the interface and you have your answer.

If you want to get more granular than the 5 minute time interval displayed by default, you can enter the interface specific "load-interval (# in seconds)" command to be more granular. 5 minutes is often way to long a time period to get an accurate reading. I tend to move it down to 30 seconds when I need to be as granular as possible.