Two types of
virtual connections
Permanent Virtual
Circuits (PVC) are set up by the operator on a permanent (or long-term) contract
basis
PVC set-up via network management tools
No signalling required
Switched Virtual
Circuits (SVC) are controlled by user signaling (ITU-T Q.2931)
Set-up and release of ATM virtual connections
requires signalling (like PSTN/ISDN)
Signalling channels are set-up on a permanent basis
Broadband ISDN
