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New Member

Frame Relay Speed

Hello. I have a question about the speed of the frame relay line that I have from WorldCom. I am getting confused between the port, pvc and cir.

This is what I have a 256kport..>256K CIR PVC..> 256K port and and pvc of 128k at each location.

From what I understand the Port is the clocking rate of the circuits at each location and the CIR is the end-to-end bandwidth but I don’t understand what the PVC is. Do I have access to 128k and each location, which give me a total amount of bandwidth of 256k.

Thanks for your help



Re: Frame Relay Speed

The PVC is just the term for the virtual circuit which is the path across the frame relay network. The CIR, or the Committed Information Rate, is the guarenteed bandwidth available over that PVC.

If the access speed at either end is higher than the CIR, then it is possible to send data at higher speeds however, if the frame cloud becomes congested, frames will be dropped and traffic will be throttled back to the CIR rate.


Re: Frame Relay Speed

Thanks. I am building a voice over frame solution and I wanted to be sure of the bandwidth available to ensure no bursting of the voice packets


New Member

Re: Frame Relay Speed

Your posting is some what confusing. Just to clarify one thing CIR is nothing more than the agreed upon gauranteed throughput . If you negotiated a 0 CIR, your gauranteed only what the providor's switch will allocate to you based on current usage. If its a slow day at the phone company you get more throughput, if it a busy day, customers with a higher CIR get priority.

In frame relay, the end points and CIR constitute a PVC. Its a way to define a logical path between two locations.

Hope this helps

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