• no-refresh (OPTIONAL): enter the keywords no-refresh to delete the ARP entry from CAM. Orto specify which dynamic ARP entries you want to delete, use this option with interface or ipip-address.• For a port channel interface, enter the keywords port-channel then a number.• For a 10-Gigabit Ethernet interface, enter the keyword TenGigabitEthernet then the slot/portinformation.• For a 40-Gigabit Ethernet interface, enter the keyword fortyGigE then the slot/port information.• For a port extender 1–Gigabit Ethernet interface enter the keyword peGigE then the pe-id/pe-stack—unit-id/port-number information.• For a VLAN interface, enter the keyword vlan then a number between 1 and 4094.NOTE: Transit traffic may not be forwarded during the period when deleted ARP entries are resolved againand re-installed in CAM. Use this option with extreme caution.ARP Learning via Gratuitous ARPGratuitous ARP can mean an ARP request or reply.During ARP learning via gratuitous ARP, the gratuitous ARP is a request. A gratuitous ARP request is an ARPrequest that is not needed according to the ARP specification, but one that hosts may send to:• detect IP address conflicts• inform switches of their presence on a port so that packets can be forwarded• update the ARP table of other nodes on the network in case of an address changeIn the request, the host uses its own IP address in the Sender Protocol Address and Target Protocol Addressfields.When a gratuitous ARP is received, the system installs an ARP entry on all three CPUs.Enabling ARP Learning via Gratuitous ARPTo enable ARP learning via gratuitous ARP, use the following command.• Enable ARP learning via gratuitous ARP.CONFIGURATION modearp learn-enableIPv4 Routing 557
