Frame Relay

Frame Relay is a packet switching protocol. Frame Relay services are provide by local Telcos, and by IntereXchange Carriers (IXCs) such as Sprint, AT&T, LDDS-Worldcom, MFS, and MCI. Frame Relay allows mesh networks to be constructed cheaply and easily since it requires less hardware to construct a mesh network.

Frame Relay, unlike PPP over dedicated leased lines, is usage sensitive, and not distance sensitive. This means that you pay for the data sent, not for the distance the data is sent, as it is with leased lines.

Frame Relay incorporates the concept of Committed Information Rate. This is the rate of data transfer that the Frame Relay provider guarantees to deliver for you. Anything over this rate is either billed at an agreed rate, or discarded if the network is congested.

The Frame Relay network is composed of hundreds of switches which can create temporary end-to-end circuits, called Permanent Virtual Circuits, between two computers. The PVCs appear just like a nailed-up leased line PPP connection to hardware and software, but in reality the circuits are built-up and torn down many times during a single transfer session.