Layer Broadcast Handling

In a Frame Relay network, the layer broadcast handling depends on the type of the broadcast.

Inverse ARP: Inverse ARP is a process that allows Frame Relay devices to map Layer 3 addresses to Layer 2 addresses. Inverse ARP frames are sent as multicast frames to address 0x03 with the destination address set to the multicast address of the protocol type used by the network layer protocol. The mapping information is learned dynamically and is stored in the Frame Relay map table.

Local broadcast: Local broadcast is a broadcast sent from a DTE device to all other DTE devices attached to the same Frame Relay switch. Local broadcasts are sent as unicast frames to the local DLCI address of the Frame Relay switch. Global broadcast: Global broadcast is a broadcast sent from a DTE device to all DTE devices in the same Frame Relay network. Global broadcasts are sent as multicast frames to address 0x0F with the destination address set to the multicast address of the protocol type used by the network layer protocol. Global broadcasts are flooded throughout the network and can cause congestion on low-speed Frame Relay links. Therefore, it is recommended to limit the use of global broadcasts in Frame Relay networks.