permanent virtual circuit (PVC)

Definition of permanent virtual circuit (PVC) in The Network Encyclopedia.

What is PVC (permanent virtual circuit)?

A form of telecommunications service for wide area networks (WANs) that provides a dedicated switched circuit between two nodes in a circuit-switched network.

How It Works

The switches of a permanent virtual circuit (PVC) are set up and configured by the telco or carrier to provide a permanent, point-to-point connection between the two nodes. These circuits are called “permanent” because the telco dedicates specific resources (switches) to your company - they can't be used by anyone else as long as you lease the service. The switches are called “virtual” because the customer does not have a physical wire connecting two networks but rather a logical connection between switches configured by the telco’s management software. In fact, the customer does not even need to know how the circuit is set up.

Graphic P-8. Permanent virtual circuit (PVC).

PVCs offer guaranteed bandwidth and extremely low latency for establishing a connection. Also, because the switching pathway is permanent, the quality of the connection does not vary with time. The result is more reliable service than switched virtual circuits (SVCs). However, PVCs are more expensive than SVCs because telco resources are dedicated to the customer and cannot be used for other purposes.

Furthermore, with a PVC you pay for the bandwidth whether or not you use it; with SVCs, the amount you pay depends on how much bandwidth you use.

PVCs are best for WAN links that carry steady, high volumes of network traffic. They are commonly used in leased lines for point-to-point WAN links between two networks.

NOTE

The term “permanent virtual circuit” is also used in frame relay networking. This type of circuit is configured in a similar fashion to those used in leased line connections.

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