Frame Relay

Frame Relay is one of the most popular WAN service deployed over the past decade. Even though several advanced technologies (such as VPN, ATM) are available today, Frame Relay still rocks and will be in near future due to its features, benefits and lower cost in comparison with other point to point wan services. 

Network providers commonly implement Frame Relay for voice (VoFR) and data as an encapsulation technique used between local area networks (LANs) over a wide area network (WAN). Each end-user gets a private line (or leased line) to a Frame Relay node. The Frame Relay network handles the transmission over a frequently changing path transparent to all end-user extensively used WAN protocols. It is less expensive than leased lines and that is one reason for its popularity. The extreme simplicity of configuring user equipment in a Frame Relay network offers another reason for Frame Relay's popularity.

Frame Relay PVCs (Permanent Virtual Circuits)	Frame Relay SVCs (Switched Virtual Circuits)
PVC is just like a leased line that is once configured will stay there until we manually reconfigure it.	SVC is just like a telephone connection that is dynamically built whenever we have data to transmit and once transmission is over it will be terminated.
If we have regular data for transmission then PVC is the best choice.	If we have periodical data for transmission then SVC is the right choice.
PVCs need a lot of manual configuration.	SVCs need less configuration in comparison with PVCs.
Once PVC is built there is no delay before data transmission.	Since SVC is built each time whenever we send data, therefore a small delay before data transmission is expected.
Whether we use it or not, we have to pay for entire billing cycle.	We need to pay only when we actually use it.