Frame Relay

• Like X.25 Frame Relay is a packet-switching technology
• uses variable-length packets
• It establishes a logical path that's called a Permanent Virtual Circuit (PVC) between end-points. PVCs take fixed paths, so a PVC is the equiva-lent of a dedicated line in a packet-switched network. The path is fixed, so network nodes don't have to waste time calculating routes. Frame relay connections operate at speeds between 56 Kbps and 1.544 Mbps because they use PVCs, and there is no built-in error checking.
• again, the PVC transmits at Data Link Layer. Because  Frame Relay uses a PVC, the entire path from end to end is known => faster because no fragmentation or reassembly or best path routing is needed
• can supply bandwidth on demand
• over digital leased-line
• Frame relay connections to a network require you to use a frame relay-compatible CSU/DSU to create the physical connection to the WAN, and a router or bridge to move traffic from the LAN to the WAN, and the WAN to the LAN, as needed.
• in summary, Frame relay costs less than a dedicated line or an ATM connection and provides data transmission rates of up to 1.544 Mbps over conventional or fiber optic media.