3com 8807 Reference Guide

C

HAPTER

 45: ARP C

ONFIGURATION

 C

OMMANDS

arp static ip-address mac-address vlan-id multi-port interface-type 
interface-number [ vpn-instance vpn-instance-name ] ]

undo arp ip-address multi-port interface-type interface-number [ vpn-instance 
vpn-instance-name ]

System view

ip-address: IP address of the ARP mapping entry.

mac-address: MAC address of the ARP mapping entry, in the format of H-H-H. For 
a multiple-outgoing-port ARP entry, this is a multicast MAC address.

vlan-id: ID of the VLAN of the static ARP entry, in the range of 1 to 4094.

interface-type: Port type.

interface-number: Port number.

For details about the above two parameters, refer to the interface command in 
port command manual.

vpn-instance-name: The VPN instance name of the VPN which the IP address 
belongs to.

Use the arp static multi-port command to add a multicast ARP port. When you 
add the first port, the system generates a multicast ARP entry.

Use the undo arp multi-port command to remove a multicast ARP port. When 
you remove the last port, the system removes the multicast ARP entry.

The multicast ARP feature allows you to associate a common unicast route to a 
Layer 2 multicast group, that is, add multiple outgoing ports for an outgoing ARP 
packet so that the packet can be sent to multiple ports. As a result, a static 
multicast ARP entry is generated. In brief, a multicast ARP entry is a static ARP 
entry with a multicast MAC address, which may correspond to multiple ports.

According to the multi-port keyword in this command, the switch decides that 
the port to be added is for a multicast ARP entry. Only one port can be added 
every time the command is executed. If the multicast ARP entry does not exist, a 
new multicast ARP entry is generated. If the multicast ARP entries exist with the 
same egress, the switch will not add a multicast ARP port.

Note that:

■

You cannot configure multicast ARP for aggregation ports. Otherwise, the 
system will prompt error message.

■

At present, the outgoing ports in the same multicast ARP entry cannot be in 
different modules.