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Appendix D: Protocols Overview
PVCs
PVCs are similar to leased lines because the connection is always present. The logical connection is established permanently by the Packet Switched Network administration. Therefore, data may always be sent, without any call setup.
Frame Relay Protocol
Frame Relay is defined as a
Frame Relay depends on the concepts of Permanent Virtual Circuits (PVCs) and Committed Information Rate (CIR).
A PVC is virtual because no wires or cables directly hook up the local and remote peers (for example, your branch library and the central library). The connection occurs in the cloud or switch at the telephone company. A PVC is permanent because as long as the computer at the telephone company is turned on, the circuit remains established.
The CIR is the contracted communication rate (bandwidth) you have negotiated with the telephone company, guaranteeing your ability to transmit at a specified minimum speed all the time. It is generally possible to transmit at much higher speeds, by virtue of the nature of frame relay, but you will always attain the CIR you negotiated.
iSPAN Serial WAN Adapter Users Guide | 187 |