Frame relay is packet switching technology. Frame relay is a high performance WAN protocol that operate at the physical and Data Link Layers of the OSI Models. Two Types of Circuits are there:
Permanent Virtual Circuits (PVCs) are similar to Leased Line. PVCs is setup for a dedicated Point – to – Point connections.
Switched Virtual Circuits (SVCs) are similar to Telephone line switched connection. SVCs is setup on a Call – by – Call basis
Three states for PVCs
Active - It means everything is UP.
Inactive - It means there is problem with the far end.
Deleted - It means problem with Router and Frame Relay provider Equipment.
LMI – Local Management Interface
The main function of Local Management Interface (LMI) is to allow the frame relay DTE and DCE to exchange the status information about the Virtual Circuits (VCs)
