We earlier discussed that Cisco routers support all network layer protocols over Frame Relay. We also know that the address-to-DLCI mapping can be accomplished both by dynamic or static mapping. Frame Relay static mapping ever depends on the network needs. To map between a next hop protocol address and DLCI destination address, the follow command syntax can be used:
frame-relay map protocol protocol-address dlci[broadcast] [ietf] [cisco].
The “ietf” parameter can be used when you want to connect a non-Cisco router.
Another parameter in the command is “broadcast”; this parameter specifies that broadcast and multicast traffic is permitted over the VC. It is permits the use of dynamic routing protocols over the VC. Due to broadcast the configuration of Open Shortest Path First (OSPF) protocol can be significantly simplified.
Frame Relay, ATM, and X.25 are non-broadcast multiaccess (NBMA) networks. Non-broadcast multiaccess (NBMA) based networks only allow data transfer from point to point, over a VC, or across a switching device. Non-broadcast multiaccess (NBMA) networks do not allow multicasting or broadcasting, therefore a single packet cannot reach to all destinations.
The single packet required to replicate the packets manually to all destinations. Using the broadcast keyword is a way to send and forward routing updates. The broadcast keyword support IPv4 broadcasts and multicasts to be propagated to all nodes. Broadcast also allows IPv6 multicasts over the PVC. When this keyword is enabled, the router converts the broadcast or multicast traffic into unicast traffic so that other nodes receive the routing updates.
The “protocol” parameters defines the supported protocol, bridging or logical link control: IPv4, IPv6, Apple Talk, decnet, dlsw, ipx, rsrb, vies, llc2 and xns.
The “procol address” defines the network layer address of the destination router interface.
The “dlci” defines t local DLCI used to connect to the remote protocol address.