Router ARP Tables Continued
A router uses ARP just as other hosts use ARP. However, the router will typically have a larger ARP table because it usually deals with more hosts.
Routers can connect to multiple networks; a typical TCP/IP host only connects to and receives ARP mappings for its local segment.
The actual number of ARP table entries depends on the amount of traffic sent between and within the various segments.
Since routers have multiple network interfaces, they also include the port numbers of their NICs in the ARP table. In this way, routers can make routing decisions for incoming packets quickly by forwarding the packets to the appropriate interface.