Frame Relay - Permanent Virtual Circuits and Committed Information Rate

Frame relay service is priced at fixed monthly fees based on the following elements, plus the cost of the access line used to connect each site to the carrier's frame relay equipment:

- The permanent virtual circuit (PVC) is a logical, predefined path or link through a carrier's network. If sites at Point A and Point B need to exchange data, the carrier defines a permanent virtual circuit between these two locations. PVCs are priced at fixed monthly fees.

- The frame relay port is the entry point, on a FR provider's switch, to the FR network. Multiple PVCs can use one port. Ports are available to variable speeds such as T-1, 56Kbps, 256Kbps and 512 Kbps.

- The committed information rate (CIR) is the minimum number of bits per second, perhaps half the capacity of the port, that the customer is guaranteed to be able to send from each site. Some customers save money by using low committed information rates. Customers can "burst," send data at the maximum speed of their FR port, if bandwidth is available.