How to find out how much of my 100Mb connection is being used

[badassmexican]

Hi,

I have a Cisco 7120 router with a 100Mb connection up and down.  I'd like to see if it's possible to find out how much of that I'm using.  

I found a post online that said to set my interface to

"load-internal 30"

and then run 

"show int fa0/0" 

 Which shows me 

30 second input rate 577000 bits/sec, 470 packets/sec

30 second output rate 324000 bits/sec, 454 packets/sec

 
Which is .57 Mb in and .32 Mb in.  Is this the right way to calculate this?

[Larry Sullivan]

Correct.  You can try "show int fa0/0 human-readable" for a more intuitive output. 

[Georg Pauwen]

Hello,

in addition to Larry's post, the txload and the rxload also give an indication of the interface saturation:

FastEthernet0/1 is up, line protocol is up
Hardware is iGbE, address is 52c1.8293.ec01 (bia 52c1.8293.ec01)
Internet address is 192.168.175.1/24
MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 128/255, rxload 128/255

In this example, 255 would be 100%, which would equal 100MB. 128 would mean 50%, or 50MB

[joepak]

Hi,

Yes that is correct. I would recommend to perform these calculations during peak hours to truly monitor the b/w that is being utilized on the link. As you know, if it's the end of the day, I wouldn't expect large amounts of bandwidth utilization nor should it be expected early in the morning :).

The formula to calculate utilization is

Utilization (U) Percentage = (Throughput/Data Rate) x 100

For example as below

5 minute input rate 3000 bits/sec,

5 minute output rate 4000 bits/sec,

Utilization Percentage (input) = (3000 / 100,000,000) x 100 = ?

Utilization Percentage (output) = (4000 / 100,000,000) x 100 = ?

Utilization Percentage (total) = [(3000 + 4000) / 100,000,000] x 100 = ?

[johnlloyd_13]

hi,

do you have any bandwidth monitoring tool? there are free and paid ones on the internet.

it's better to use these tools rather than monitoring your 100 meg BW manually over time.