Frame relay is an interface used for wide-area networking. It is used to reduce the cost of connecting remote sites, in any application that would typically use expensive leased circuits. The more locations you have, the greater your savings. With the right carrier service, frame relay network links may be quickly adjusted to meet changes to applications and network topology.
Traditional high-speed WANs are built on high-capacity leased lines, which often take months to order and install. Because network managers must react quickly when a new application, organizational unit, business partner or location is needed, leased-line networks often present a roadblock. Using frame relay, backbone changes can be quickly programmed by the carrier, saving the long installation delays and high costs associated with running physical circuits.
WAN designers also have more flexibility when using frame relay. Whereas physical circuits are typically sized in fractions of 56 or 64 kilobits, virtual circuits may be defined with finer granularity, often in fractions of 4 kilobits. Virtual circuits are directional, allowing the send and receive path to be of different sizes if necessary. Frame relay is a form of statistical multiplexing, a method of dynamically allocating transmission bandwidth to more efficiently share high-cost links. In this way, a single access line can support connections to many remote sites.