Frame Relay is a connection-oriented data transport service operating at speeds ranging from 56 Kbps to 44 Mbps. The data is transmitted from the end-device terminal, packaged into variable length frames (packets), and transported through the network on predefined logical links. Frame Relay was developed to exploit the high quality and bandwidths offered by digital, electrical and fiber optic facilities.

Frame Relay is best suited for "bursty" data applications rather than those where a constant data stream is required. AT&T offers Permanent Virtual Circuit (PVC) service. PVCs are end-to-end, bi-directional channels that provide the look and feel of a private line network without the need for dedicated bandwidth. A PVC is created when service is established and taken down when service is discontinued.

Frame Relay is in many ways similar to leased line service. At subscription time, a connection is "nailed-up" within the service provider network between two subscriber endpoints. Data going between these two points always travels over the same fixed path, and arrives in the same order that it was sent. Because these connections are set at subscription time in the Frame Relay Network and not by the subscriber's equipment, they are relatively permanent.

Because of this "virtual" nature, Frame Relay is also in some ways similar to an Ethernet interface. Like an Ethernet interface, a single Frame Relay User Network Interface (UNI) can be used to transmit data directly to many destinations. The most important difference is that Ethernet is contention based while Frame Relay provides full connectivity bandwidth into and through the Frame network.

A subscriber uses the Frame Relay technology as an alternative to leasing physical lines to connect their computing environment (i.e., LANs). The purpose of a Frame Relay network is to provide an end user with a high-speed virtual private network (VPN) capable of supporting applications with large bandwidth requirements. With Frame Relay, many virtual connections may be provisioned over a single physical access circuit.

AT&T handles the management and upkeep of the Frame Relay network. This allows the subscriber to devote more personnel and resources to supporting the application needs of their end users. Frame Relay is fast, inexpensive, flexible and connection-oriented.