User Manual Part 2

Wi-Fi Array
282 Configuring the Wi-Fi Array
18. ARP Filtering: Address Resolution Protocol finds the MAC address of a
device with a given IP address by sending out a broadcast message
requesting this information. ARP filtering allows you to reduce the
proliferation of ARP messages by restricting how they are forwarded
across the network.
You may select from the following options for handling ARP requests:
• Off: ARP filtering is disabled. ARP requests are broadcast to radios
that have stations associated to them.
• Pass-thru: The Array forwards the ARP request. It passes along only
ARP messages that target the stations that are associated to it. This is
the default value.
• Proxy: The Array replies on behalf of the stations that are associated
to it. The ARP request is not broadcast to the stations.
Note that the Array has a broadcast optimization feature that is always on
(it is not configurable). Broadcast optimization restricts all broadcast
packets (not just ARP broadcasts) to only those radios that need to
forward them. For instance, if a broadcast comes in from VLAN 10, and
there are no VLAN 10 users on a radio, then that radio will not send out
that broadcast. This increases available air time for other traffic.
19. Fast Roaming Mode: This feature utilizes the Xirrus Roaming Protocol
(XRP) ensuring fast and seamless roaming capabilities between IAPs or
Arrays at Layer 2 and Layer 3 (as specified in Step 20), while maintaining
security. Fast roaming eliminates long delays for re-authentication, thus
supporting time-sensitive applications such as Voice over Wi-Fi (see
“Understanding Fast Roaming” on page 270 for a discussion of this
feature). XRP uses a discovery process to identify other Xirrus Arrays as
fast roaming targets. This process has two modes:
• Broadcast — the Array uses a broadcast technique to discover other
Arrays that may be targets for fast roaming.
• Tunneled — in this Layer 3 technique, fast roaming target Arrays
must be explicitly specified.