Novell NETWARE 6-DOCUMENTATION Manual page 1436

Mapping Internet Addresses to Physical Addresses
Address Resolution Cache
When an IP address is mapped to a physical, or MAC, address, ARP is used
on broadcast networks such as Ethernet, token ring, and ARCnet. When a
node uses IP to send a packet, it must determine which physical address on the
network corresponds to the destination IP address. To find the physical
address, the node broadcasts an ARP packet containing the destination IP
address. The node with the specified destination IP address sends its physical
address back to the requesting node.
To speed packet transmissions and reduce the number of broadcast requests
that must be examined by every node on the network, each node keeps an
address resolution cache. Each time the node broadcasts an ARP request and
receives a response, it creates an entry in its address resolution cache. The
entry maps the IP address to the physical address.
When the node sends an IP packet, it looks up the IP address in its cache and
uses the physical address, if found. The node broadcasts an ARP request only
if the IP address is not in its cache.
ARP Cache Update Timeout
ARP Cache Update Timeout is a configurable parameter used to specify the
timeout period for an entry to be removed from the ARP table, if the entry has
not been updated. The ARP Cache Update Timeout value should be greater
than or equal to the ARP Cache Stale Timeout value.
ARP Cache Stale Timeout
ARP Cache Stale Timeout ia a configurable parameter used to specify the
timeout period for an entry to be removed from the ARP table, if the entry has
not been used for some time. The ARP Cache Stale Timeout value should be
less than or equal to the ARP Cache Update Timeout value.
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Understanding