You have a broadcast-based application that you want to treat as multicast so that it can cross the network.
Cisco has a special feature called an IP Multicast Helper, which you can use to convert broadcast packets to multicast packets. Then you can use PIM to send these packets throughout the network. At the last-hop routers you can then convert the multicast packets back to broadcast. This is useful for older broadcast-based applications that do not support multicast transmission.
Router1 is the first-hop
router, or the one closest to the broadcast source, which is on the
interface FastEthernet0/0. It converts broadcast
packets with UDP port
on this interface into multicast packets in group
configure terminalEnter configuration commands, one per line. End with CNTL/Z. Router1(config)#
permit any any udp
deny any any udpRouter1(config)#
ip directed broadcastRouter1(config-if)#
ip multicast helper-map broadcast
ip pim sparse-dense-modeRouter1(config)#
ip forward-protocol udp
The last-hop router’s configuration is similar, except that it must be configured to turn multicast packets for this group back into broadcasts:
configure terminalEnter configuration commands, one per ...