Frame relay complements and provides a mid-range service between ISDNwhich offers bandwidth at Kbps, and Asynchronous Transfer Mode ATMwhich operates in somewhat similar fashion to frame relay but at speeds of For most services, the network provides a permanent virtual circuit PVCwhich means that the customer sees a continuous, dedicated connection without having to pay for a full-time leased linewhile the service-provider figures out the route each frame travels to its destination and can charge based on usage.
It tries to keep the network operating at its desired equilibrium point so that a certain quality of service QoS for the network can be met.
DCEs are managed by the carriers and provide switching and associated services. However, under certain circumstances, voice and video transmission do use Frame Relay. Congestion control in Frame Relay networks includes the following elements: Admission Control.
For many purposes, leased lines are gradually being replaced by DSL and metro Ethernet.
Note that this DLCI has only local significance. It requires a dedicated connection during the transmission period.