User guide

Availability, mobility, and controller functionality
Summit WM Series WLAN Switch and Altitude Access Point Software Version 4.1 User Guide
154
From the viewpoint of an Altitude AP, if a Summit WM series switch or the connection to it fails, the
Altitude AP begins its discovery process. The Altitude AP is directed to the appropriate backup
controller of the pair. This connection may require the Altitude AP to reboot. Users on the Altitude AP
must log in again and be authenticated on the second Summit WM series switch.
NOTE
The availability feature provides APs with a list of interfaces to which the AP should attempt to automatically
connect to when a connection with an active controller link is lost. The provided list identifies the local active
interfaces (enabled on the primary and backup controllers) 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 AP
automatically scans (pings) all addresses in its availability interface list. The AP will then connect to the highest
priority interface that responds to its probe.
Availability prerequisites
Before you begin, ensure you have completed the following:
● Choose the primary and secondary Summit WM series switches.
● Verify the network accessibility for the TCP/IP connection between the two switches. The
availability link is established as a TCP session on port 13907.
● Set up a DHCP server for AP subnets to support Option 78 for SLP, so that it points to the IP
addresses of the physical interfaces on both Summit WM series switches.
Now set up each Summit WM series switch separately. One method is as follows:
1 In the AP Registration screen, set up each Summit WM series switch in Stand-alone Mode and
Secure Mode (allow only approved Altitude APs to connect).
2 In the Topo lo gy tab, define a WM-AD on each Summit WM series switch with the same SSID. The
IP addresses must be unique. For more information, “Topology for a WM-AD” on page 98. A
Summit WM series switch WM200/2000 VLAN Bridged WM-AD can permit two controllers to share
the same subnet (different IP addresses). This setup provides support for mobility users in a VLAN
Bridged WM-AD.
3 On both Summit WM series switches, set the Registration Mode to Allow only approved so that no
more Altitude APs can register unless they are approved by the administrator.
4 In the AP Registration screen, enable the two Summit WM series switches as an availability pair.
5 On each Summit WM series switch, in the Access Approval screen, check the status of the Altitude
APs and approve any APs that should be connected to that controller.
System AP defaults can be used to assign a group of WM-ADs to the foreign APs:
● If the APs are not yet known to the system, the AP will be initially configured according to AP
default settings. To ensure better transition in availability, it is recommended that the AP default
settings match the desired WM-AD assignment for failover APs.
● AP assignment to WM-ADs according to the AP default settings can be overwritten by manually
modifying the AP WM-AD assignment. (For example, select and assign each WM-AD that the AP
should connect to.)
● If specific foreign APs have been assigned to a WM-AD, those specific foreign AP assignments
are used.