User's Guide

Table Of Contents
Availability and session availability
hwc_fastfailover.fm
Availability
9034530-02, March 2010
382 HiPath Wireless Controller, Access Points and Convergence Software V7.11, User Guide
During the failover event when the Wireless AP connects to the secondary
controller, the users are disassociated from the Wireless AP. Consequently, the
users must log on again and be authenticated on the secondary controller before
the wireless service is restored.
Note: If you want the mobile user’s session to be maintained, you must use the
‘session availability’ feature that enables the primary controller’s Wireless APs to
failover to the secondary controller fast enough to maintain the session
availability (user session). For more information, see Section 7.4, “Session
availability”, on page 392.
The availability feature provides Wireless APs with a list of interfaces. The
Wireless AP should attempt to connect automatically to these interfaces when the
connection with an active controller link is lost. The provided list identifies the
local active interfaces for the active controller as well as the active interfaces for
the backup controller. The list is sorted by top-down priority. If the active link is lost
(poll failure), the Wireless AP automatically scans (pings) all addresses in its
availability interface list. The Wireless AP will then connect to the highest priority
interface that responds to its probe.
7.1.1 Events and actions in availability
If one of the HiPath Wireless Controllers in a pair fails, the communication
between the two HiPath Wireless Controllers stops. This triggers a failover
condition following which a critical message is displayed in the information log of
the secondary HiPath Wireless Controller.
After a Wireless AP on the failed HiPath Wireless Controller loses its connection,
it will try to connect to all enabled interfaces on both controllers without rebooting.
If the Wireless AP is not successful, it will begin the discovery process. If the
Wireless AP is not successful in connecting to the HiPath Wireless Controller
after five minutes of attempting, the Wireless AP will reboot if there is no Bridge
traffic locally at the AP topology associated to it.