ARP + Frame Relay.

Hi Experts,

R3(config)#int fa0/0
R3(config-if)#arp ?
  arpa         Standard arp protocol
  authorized   Only allow internal authorized ARP entry
  frame-relay  Enable ARP for a frame relay interface
  probe        Set ARP probe parameters
  snap         IEEE 802.3 style arp
  timeout      Set ARP cache timeout

R3(config-if)#arp frame-relay ?
  <cr>



Can someone please tell me what is arp frame-relay?