svc - Computer Definition
A shared path established between two hosts through a packet network on command, i.e., via signaling as the call is placed. Once the path is selected, all packets in a given session travel the same path, which is selected in consideration of both the condition of the network and the load on it at the instant the connection is required. Thereby, an SVC bypasses failed and congested switches and circuits and improves overall performance through automatic load balancing.Although SVCs are defined in frame relay specifications, they are unusual in public networks due to the carrier's fear that frame relay SVCs would cannibalize more expensive services like ISDN and long distance voice. Rather, frame relay networks employ permanent virtual circuits (PVC), which are predetermined, preprogrammed paths. Globally, X.25 networks largely are based on SVCs. See also channel, circuit, frame, frame relay, load balancing, packet, path, PVC, virtual circuit, and X.25.
(1) (Switched Virtual Circuit) A network connection that is established at the time the transmission is required and disconnected when the session is completed. SVCs are normally implemented in connection-oriented systems such as the analog telephone network and ATM networks. Contrast with PVC.
(2) (Scalable Video Coding) An extension to the Advanced Video Coding (AVC) standard to accommodate rendering devices with different processing capabilities and/or degraded transmission paths. SVC allows low-resolution formats to travel as subsets alongside the high-resolution video. The subsets may eliminate frames or contain reduced frame sizes or both. Rather than display high-resolution video poorly, SVC enables lesser-quality video to flow smoothly on low-bandwidth devices and channels. See H.264.
(3) (SuperVisor Call) A mainframe instruction that passes control to the operating system.