A permanent virtual circuit (PVC) is a logical network connection provisioned in advance between specified endpoints. It is maintained as part of the network service until it is removed or the service ends; “permanent” does not mean it is an unbreakable physical cable.
What a permanent virtual circuit is
A PVC provides a virtual link across a network between defined endpoints. A provider or network operator sets it up ahead of use, rather than having the endpoints establish a new connection each time they communicate. In ATM documentation, PVC may also mean “permanent virtual connection.” Cisco uses the term in ATM and Frame Relay contexts. Cisco’s virtual-circuit terminology reference explains that usage.
A PVC is a logical service, not a dedicated physical wire. Cisco’s ATM FAQ describes an ATM PVC as a non-redundant circuit through a service-provider network, provisioned with the bandwidth purchased by the customer. That is a description of Cisco’s ATM service context, not a guarantee that all PVCs have the same bandwidth or resilience. Cisco’s ATM PVC and SVC FAQ was updated February 14, 2019.
How a PVC differs from an SVC
A switched virtual circuit (SVC) is established dynamically when needed through network signaling. Cisco’s ATM FAQ says an SVC can be removed after an idle interval; a PVC, by contrast, is provisioned in advance and remains configured for its service term.
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| Feature | PVC | SVC |
|---|---|---|
| How it is established | Manually provisioned in Cisco’s ATM example by a network operator. | Established dynamically on demand through network signaling. |
| How long it lasts | Maintained for the service term. Cisco gives a month to several years as an ATM service example, not a universal technical limit. | Can be ended after an idle interval, according to Cisco’s ATM description. |
| Operational effect | The connection configuration is maintained in advance. | Endpoints establish the connection when needed; after a failure, the call may need to be initiated again. |
The comparison reflects Cisco’s ATM documentation. Timeout behavior and other details depend on the equipment and service; Cisco’s stated default SVC idle timeout should not be assumed for every ATM system.
How PVC configuration works in Cisco ATM guidance
In Cisco’s IOS XE 17 ATM configuration guide, a PVC must be configured on both the router and the ATM switch. It stays active until it is removed from either configuration. The guide identifies a PVC using a virtual path identifier and virtual channel identifier (VPI/VCI), alongside interface protocol and encapsulation settings. Cisco’s IOS XE 17 ATM configuration guide gives the platform-specific details.
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Those settings are not universal setup instructions: commands, identifier ranges, signaling, and encapsulation depend on the equipment and service. Cisco also describes a permanent virtual path (PVP) as a set of PVCs, providing an ATM hierarchy in which multiple virtual circuits can be grouped. See Cisco’s virtual-path reference for that context.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.What “permanent” means in practice
“Permanent” describes how the logical connection is provisioned and maintained, not a promise of uninterrupted physical connectivity. A PVC remains part of the configured service until it is removed or the service is terminated. Network equipment, provider arrangements, and the particular technology determine its actual behavior and resilience.
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