NAME

arp − Address Resolution Protocol

DESCRIPTION

Arp is a protocol used to dynamically map between DARPA Internet and 10Mb/s Ethernet addresses or DOMAIN ring node IDs on a local area network. 

Arp caches Internet-local net address mappings.  When an interface requests a mapping for an address not in the cache, arp queues the message which requires the mapping and broadcasts a message on the associated network requesting the address mapping.  If a response is provided, the new mapping is cached and any pending messages are transmitted.  Arp will queue at most one packet while waiting for a mapping request to be responded to; only the most recently “transmitted” packet is kept.