bandwidth command

[sarahr202]

Hi every body.

Let say we have two switches ,sw1 and sw2 with 10/100 ports.

Both are connected as:

sw1 f0/1----------f0/1 sw2

Now if i configure sw1 as:

int f0/1

bandwidth 10,000K ( same thing 10Mb)

sw2:

int f0/1

bandwidth 10,000K

will the link operate at 10M? I understand if i use the speed command on both switches,. , it will sure operate at 10M. But i am just wondering how bandwidth command affects the speed in the above case.

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thanks a lot.

[Jerry Ye · Accepted solution]

Hi Sarah,

The port will not operate at 10M. The bandwidth command will only affect the routing metric calculation of the link. Also, it will also influence QoS.

HTH,

jerry

[srue · Accepted solution]

the bandwidth command affects routing metrics only...to change the actual speed of a link, use the 'speed' command.

[Istvan_Rabai · Accepted solution]

Hi Sarah,

The bandwidth command will not affect the actual port speed.

On layer3 ports, you can set the administrative bandwidth to influence routing protocol cost calculations or QoS settings.

For example, OSPF calculates the interface cost by the following formula:

Cost = 100,000,000 / bandwidth.

(bandwidth in this case is taken as bits per second)

Cheers:

Istvan

[John Blakley · Accepted solution]

The bandwidth command doesn't affect the actual speed. It's used for calculations like the others have mentioned.

HTH,

John