Chapter 21. ARP: Address Resolution Protocol
21.1. Introduction
ARP, the Address Resolution Protocol, handles the translation of 32-bit IP addresses into the corresponding hardware address. For an Ethernet, the hardware addresses are 48-bit Ethernet addresses. In this chapter we only consider mapping IP addresses into 48-bit Ethernet addresses, although ARP is more general and can work with other types of data links. ARP is specified in RFC 826 [Plummer 1982].
When a host has an IP datagram to send to another host on a locally attached Ethernet, the local host first looks up the destination host in the ARP cache, a table that maps a 32-bit IP address into its corresponding 48-bit Ethernet address. If the entry is found ...
Get TCP/IP Illustrated now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.
