Originally developed as an interim solution and stepping stone to ATM technology, Frame Relay has quickly become the first choice for many corporations faced with connecting their LANs to remote offices. As file transfer and remote access to large databases become more critical to businesses, Frame Relay is an excellent choice for many reasons.

Frame Relay is a layer 2 protocol. It encapsulates data (including protocol headers from other network technologies) into a frame and sends it over a Frame Relay network to its destination. If a message originates in a TCP/IP network, the TCP/IP header information is encapsulated into a Frame Relay frame and sent to its destination. If the destination is also a TCP/IP network, the header information can then be used to continue routing the data over the TCP/IP connection.

The unique feature of Frame Relay is that it does not provide any error detection/correction or real flow control (between devices). The only flow control provided in Frame Relay is used by the network to prevent network congestion. Even then the procedures are very simple, requiring little or no processing on the part of the network devices. That is the real intent of Frame Relay, to remove all of the requirements for processing within the network and let the upper-layer protocols (such as TCP/IP or ISDN) provide those procedures. This means the end devices must provide the flow control procedures and error detection/correction outside of the network. The end result is a very efficient network protocol that...