Mohammed, thanks for your help. The interface is serial as you thought. If I set the bandwidth statement to 768, will that affect the circuits ability to burst up to port speed?

Hi,

You are very welcomed. You can't burst up to the port speed if you are contracted to a 768 PVC (according to your contract with your service provider, most probably the provider has policed your PVC with this value), and thus you need to configure the interface with the actual PVC bandwidth in order for the QoS to operate in the desired manner, baring in mind that the bandwidth command doesn't affect the physical speed of the interface, it will be used for the QoS calculations, which will eventually be used for adjusting your QoS behavior.

BR,

Mohammed Mahmoud.

Hi Mohammed. We have the contracted 768 rate, but are allowed to burst up to port speed by our carrier. Would you recommend I just enable traffic shaping at the 768 bandwidth and not burst? Thanks.

Hi Jason,

What kind of QoS are we talking about here, and what is the nature of your traffic ?

BR,

Mohammed Mahmoud.

We are mapping traffic to four classes (per our carrier) with class 1 for voice, 2 and 3 for data, and 4 is the default. My main concern is how the traffic and QOS markings would be affected by allowing the circuit to burst to non-guaranteed speeds.

Whether to burst depends on whether you're able to tolerate packet lost or additional latency when sending above CIR. (In theory, if you keep to CIR, you should obtain performance similar to a leased line of the same bandwidth.)

In practice, especially at a T-1 rate, if you're using a major carrier in the US or Canada, using full port speed is seldom an issue.

There is a middle of the road approach. You can often configure traffic shaping to use full port speed but if frame-relay congestion is seen, it will automatically reduce speed to your CIR rate. The shaper will increase speed, back up to full port rate, if no new congestion is detected.

Hint:

If you have asymmetric bandwidth connections to the frame cloud, the higher bandwidth connection should have a shaper used to limit bandwidth to no more than the far side's port rate.

No need to apologize, but thoughtful of you to do so.