Allied Telesis AT-8600, RAPIER I Adding Static ARP Entries with Multicast MAC Addresses, Show ip

Software Version 2.8.1 69

Command Changes

The following table summarises the new and modified commands:

Command	Change
set ip arpwaittimeout	New command
show ip	New Arp wait timeout field

Adding Static ARP Entries

Accepting Packets

with Conflicting

Addresses

Adding Static ARP Entries with Multicast MAC Addresses

This Software Version allows you to add ARP entries with multicast MAC addresses and allows the router or switch to accept packets with unicast IP addresses and multicast MAC addresses. It introduces the enable ip macdisparity and disable ip macdisparity commands to support this.

Valid ARP entries are normally restricted to unicast IP with unicast MAC addresses. However, ARP entries can be configured with multicast MAC addresses when macdisparity is enabled. Static ARP entries with multicast MAC addresses are necessary for some third party networking solutions, such as server clustering.

Before you can add an ARP entry with a multicast MAC address, you must enable macdisparity using the command:

enable ip macdisparity

Once this feature is enabled, you can add an ARP entry with a multicast MAC address using the add ip arp command.

Enabling macdisparity also allows the router or switch to accept packets with conflicting IP and MAC addresses. Normally the router or switch discards these packets as being invalid.

Conflicting IP and MAC addresses include:

■A multicast IP address with a unicast MAC address

■A unicast IP address with a multicast MAC address

macdisparity is disabled by default. When disabled, only ARP entries with unicast IP and MAC addresses can be added, and packets with conflicting addresses are discarded. Other routers or switches in the network may not accept packets with conflicting addresses unless configured to. To disable this functionality, use the command:

disable ip macdisparity

ARP entries with multicast MAC addresses must be removed before the disable ip macdisparity command will work. To see details on the current ARP entries, use the command:

show ip arp

To see whether macdisparity is enabled or disabled, use the command:

show ip

Software Version 2.8.1 C613-10477-00 REV B