Frame Relay Access to Other Networks

Frame relay is an access technology in which customers' packets are put into frames. In addition to LAN-to-LAN connectivity, it is used to access the following types of networks:

• Frame relay networks that carry traffic on asynchronous transfer mode (ATM) switches
• MPLS (Multiprotocol Label Switching) virtual private networks
• The public Internet

Equipment on customer premises that converts Ethernet local area network packets into frames is called a Frame Relay access device (FRAD). It is often a card within the router. Each frame has bits called the flag, telling the network when the user data (frame) starts and when it ends. There also are addressing and destination bits in the frame for billing and routing purposes so that the FR provider knows where to route and bill each frame.

Customers' frames are sent to ports on the carrier's network. Routers at the carrier's central office convert the customer data to a format compatible with the carrier's network and send it to the core network.