In Frame Relay, PVC stands for a Permanent Virtual Circuit.
Frame Relay is a telecommunications technology that puts data into variable-size units called frames. A key characteristic highlighted in the reference is that it leaves any necessary error correction or retransmission of data up to the endpoints, a design choice that helps speed up data transmission.
For most Frame Relay services, the network establishes and maintains a connection known as a Permanent Virtual Circuit (PVC).
Understanding Permanent Virtual Circuits (PVCs)
A PVC in Frame Relay is essentially a preconfigured, dedicated path established between two endpoints across the Frame Relay network. Unlike switched virtual circuits (SVCs) which are set up on demand and torn down when communication ends, PVCs are permanent connections that are always active and available for data transfer between the two specific locations.
Key Aspects of PVCs in Frame Relay
- Always On: Once configured, a PVC is available 24/7, making it suitable for connecting sites that need constant communication.
- Preconfigured: The path and resources for a PVC are set up by the service provider when the service is ordered and installed.
- Cost-Effective: PVCs are often used for sites with consistent traffic flow, offering a predictable cost structure typically based on bandwidth.
- Identified by DLCI: Each PVC is uniquely identified at the Frame Relay interface by a Data Link Connection Identifier (DLCI).
| Feature | Permanent Virtual Circuit (PVC) |
|---|---|
| Connection | Always on, preconfigured |
| Setup | Established by service provider |
| Usage | Constant, predictable traffic |
| Addressing | Uses DLCI to identify specific circuits |
By relying on PVCs for most services, Frame Relay provides a reliable, semi-permanent connection over its efficient, frame-based network, leveraging the endpoint devices for error handling to optimize speed.
