Just saw the 12.4 command reference, there is a command named "arp [arpa|frame-realy|snap]". And it also show us an example, which is encble frame-relay service under Ethernet:
R7(config)#int e0/0
R7(config-if)#arp frame-relay
Don't know what is the used for?
why we need to enable frame-relay service under Ethernet itnerface ?