3Com 4.2.2 manual Table C-2Comparison of SVC and PVC, Svc Pvc

An Introduction to ATM and VLAN Management Basics C-5

example, SNMP). Permanent connections generally remain established for long periods of time. These connections are not dynamically checked and reinitiated.

The major features of a PVC include:

■Connections initiated by network administrator.

■Connections established and released manually.

■Long-term duration connections.

■Both point-to-point and point-to-multipoint connections can be established.

Switched Virtual Channels (SVC) An SVC dynamically defines connections as they are needed and releases them when complete, using signaling complying with ATM Forum UNI standards. By using an SVC, ATM devices (for example, a LAN Emulation UNI and an ATM switch) can exchange connection characteristics (for example, QOS, VPI/VCI) when establishing connections. These connections remain active for an arbitrary amount of time and depend upon application demand. Both point-to-point and point-to-multipoint connections can be established. An SVC eliminates the need for an external management station for setting up virtual channels.

The major features of an SVC include:

■Connections initiated by the user/application.

■Connections established and released dynamically.

■Connections established via the signalling protocol.

■Varied connection duration.

Table C-2 compares SVC and PVC connections.

Table C-2Comparison of SVC and PVC

SVC	PVC
Demand connections	Permanent connections
Not automatically re-established	Automatically re-established after
after network failure	network failure
Remain active for arbitrary amount	Remain active for long periods of
of time	time