Reference Guide

arp cachesize
This command configures the ARP cache size. The ARP cache size value is a platform specific integer
value. The default size also varies depending on the platform.
Format arp cachesize platform specific integer value
Mode Global Config
no arp cachesize
This command configures the default ARP cache size.
Format no arp cachesize
Mode Global Config
arp dynamicrenew
This command enables the ARP component to automatically renew dynamic ARP entries when they
age out. When an ARP entry reaches its maximum age, the system must decide whether to retain or
delete the entry. If the entry has recently been used to forward data packets, the system will renew the
entry by sending an ARP request to the neighbor. If the neighbor responds, the age of the ARP cache
entry is reset to 0 without removing the entry from the hardware. Trac to the host continues to be
forwarded in hardware without interruption. If the entry is not being used to forward data packets, then
the entry is deleted from the ARP cache, unless the dynamic renew option is enabled. If the dynamic
renew option is enabled, the system sends an ARP request to renew the entry. When an entry is not
renewed, it is removed from the hardware and subsequent data packets to the host trigger an ARP
request. Trac to the host may be lost until the router receives an ARP reply from the host. Gateway
entries, entries for a neighbor router, are always renewed. The dynamic renew option applies only to
host entries.
The disadvantage of enabling dynamic renew is that once an ARP cache entry is created, that cache
entry continues to take space in the ARP cache as long as the neighbor continues to respond to ARP
requests, even if no trac is being forwarded to the neighbor. In a network where the number of
potential neighbors is greater than the ARP cache capacity, enabling dynamic renew could prevent
some neighbors from communicating because the ARP cache is full.
Default
Disabled
Format arp dynamicrenew
Mode Privileged EXEC
no arp dynamicrenew
This command prevents dynamic ARP entries from renewing when they age out.
Format
no arp dynamicrenew
Mode Privileged EXEC
Routing Commands
ExtremeSwitching 200 Series: Command Reference Guide for version 01 .02.04.0007 501