User Guide

Wi-Fi Array
264 Configuring the Wi-Fi Array
• Pass-thru: The Array forwards the ARP request. It passes along only
ARP messages that target the stations that are associated to it.
• 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.
17. 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 18), 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 253 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.
To enable fast roaming, choose Broadcast or Tu n n e l e d , and set additional
fast roaming attributes (Step 19). To disable fast roaming, choose Off. If
you enable Fast Roaming, the following ports cannot be blocked:
• Port 22610—reserved for Layer 2 roaming using UDP to share PMK
information between Arrays.
• Ports 15000 to 17999—reserved for Layer 3 roaming (tunneling
between subnets).