Frame Relay English

¿What is a Frame Relay?

 Frame Relay (or Frame-mode Bearer Service) is a frame relay communication technique for virtual circuit networks, introduced by the ITU-T from recommendation I.122 of 1988. It consists of a simplified form of technology packet switching that transmits a variety of frame sizes or frames ("frames") for data, perfect for transmitting large amounts of data.

The Frame Relay technique is used for a high-speed voice and data transmission service that allows the interconnection of geographically separated local area networks at a lower cost.

TYPES OF FRAME-RELAY CONNECTIONS

There are two ways to set the VC for operation:

A. PVC: Permanent virtual circuit.

Virtual circuit that is established permanently. PVCs save bandwidth associated with the establishment and cutting of circuits, if certain virtual circuits must exist at all times. The PVC, permanent virtual circuits, are pre-configured by the communications company and once configured it only works in DATA TRANSFER and IDLE mode.

B.  SVC:

Switched virtual circuit. Virtual circuit that is established dynamically on request and that is interrupted when the transmission is complete. SVCs are used when data transmission is sporadic.

The SVC, switched virtual circuits, are defined dynamically by sending signaling messages (CALL SETUP, DATA TRANSFER, IDLE, CALL TERMINATION).

2. WHAT IS THE DLCI

It indicates the way to follow, for which CV the Switch must pass. They are managed and assigned by the ISP and only have local importance because there could be other DLCIs in other links. When the Frame Relay Switch receives the request it responds by informing the local DLCIs of the PVCs to the remote routers.



For each active DLCI, the routers send an inverse ARP packet that contains the IP address corresponding to each Virtual Circuit. Remote routers create tables that include local DLCIs and IP addresses.