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Configuring the ARP Cache (Resolved Addresses)

A terminal attempting to contact another host broadcasts the IP address of the host via the ARP protocol and receives the host's Ethernet address. These resolved addresses are maintained in the terminal's ARP cache, a local table of resolved addresses. The terminal checks its ARP cache before attempting to contact a host to see if the address has already been resolved.

The tcpip-arp-cache parameter contains all of the addresses that ARP has resolved or attempted to resolve (Setup -> Change Setup Parameters -> ARP -> ARP Cache). Table 5-2 lists the entries in a row in each row of the table.

You can manually add entries to the ARP cache if necessary.

Table 5-2 tcpip-arp-cache Table Entries
Table Entry
Possible Values
Result
ethernet-address default 00:00:00:00:00:00
ethernet address The Ethernet address the host supplies in response to the ARP request from the terminal.
ip-address default 0.0.0.0
IP address The IP address broadcast by the terminal.
type default incomplete
incomplete The IP address could not be resolved to an Ethernet address.
dynamic This completed entry is subject to automatic deletion after the timeout elapses.
static This entry is not subject to automatic deletion.
time-since-last-use default 0
integer The amount of time (in minutes) since this entry was used by the terminal. Range: 0 - 255.

The lifetimes of the dynamic and incomplete entries in the tcpip-arp-cache table are governed by the following parameters.

The tcpip-arp-complete-entry-timeout parameter specifies how long a dynamic ARP table entry should be allowed to exist without being used before it is automatically deleted (Setup -> Change Setup Parameters -> ARP -> Complete Entry Timeout).

Table 5-3 tcpip-arp-complete-entry-timeout Parameter
Possible Values
Result
default 20
integer How long to wait (in minutes) before deleting an unused complete entry. Range: 1 - 255.

The tcpip-arp-incomplete-entry-timeout parameter specifies how long an incomplete ARP table entry should be allowed to exist before it is automatically deleted (Setup -> Change Setup Parameters -> ARP -> Incomplete Entry Timeout).

Table 5-4 tcpip-arp-incomplete-entry-timeout Parameter
Possible Values
Result
default 1
integer How long to wait (in minutes) before deleting an incomplete entry. Range: 1 - 255.



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