User's Manual

Table Of Contents
3/11/05 Primary, Secondary, and Tertiary Cisco Wireless LAN Controllers
OL-7426-02
Tertiary Cisco Wireless LAN Controllers to the Cisco 1000 Series lightweight access point, and reboot
the Cisco 1000 Series lightweight access point so it reassociates with its Primary, Secondary, or
Tertiary Cisco Wireless LAN Controller.
About the Primary, Secondary, and Tertiary Cisco Wireless LAN ControllersPrimary, Secondary, and Tertiary Cisco
Wireless LAN Controllers
In Multiple-Cisco Wireless LAN Controller Deployments networks, Cisco 1000 Series lightweight access
points can associate with any Cisco Wireless LAN Controller on the same subnet. To ensure that each
Cisco 1000 Series lightweight access point associates with a particular Cisco Wireless LAN Controller,
the operator can assign Primary, Secondary, and Tertiary Cisco Wireless LAN Controllers to the Cisco
1000 Series lightweight access point.
When a Cisco 1000 Series lightweight access point is added to a network, it looks for its Primary,
Secondary, and Tertiary Cisco Wireless LAN Controllers first, then a Master Cisco Wireless LAN
Controller, then the least-loaded Cisco Wireless LAN Controller with available Cisco 1000 Series light-
weight access point ports. Refer to Cisco Wireless LAN Controller Failover Protection for more
information.
About Client RoamingClient Roaming
The Cisco SWAN supports seamless client roaming across Cisco 1000 Series lightweight access points
managed by the same Cisco Wireless LAN Controller, between Cisco Wireless LAN Controllers in the
same Controller Mobility Group
on the same subnet, and across Cisco Wireless LAN Controllers in the
same Controller Mobility Group on different subnets. The following chapters describe the three modes
of roaming supported by the Cisco SWAN.
Same-Cisco Wireless LAN Controller (Layer 2) RoamingSame-Cisco Wireless LAN Controller (Layer 2) Roaming
Each Cisco Wireless LAN Controller supports same-Cisco Wireless LAN Controller client roaming across
Cisco 1000 Series lightweight access points managed by the same Cisco Wireless LAN Controller. This
roaming is transparent to the client, as the session is sustained and the client continues using the same
DHCP-assigned or client-assigned IP Address. The Cisco Wireless LAN Controller provides DHCP func-
tionality be providing a relay function. Same-Cisco Wireless LAN Controller roaming is supported in
Single-Cisco Wireless LAN Controller Wireless LAN Controller Deployments
and Multiple-Cisco Wireless
LAN Controller Deployments.
Inter-Cisco Wireless LAN Controller (Layer 2) RoamingInter-Cisco Wireless LAN Controller (Layer 2) Roaming
Similarly, in Multiple-Cisco Wireless LAN Controller Deployments, the Cisco SWAN supports client
roaming across Cisco 1000 Series lightweight access points managed by Cisco Wireless LAN Controllers
in the same Controller Mobility Group and on the same subnet. This roaming is also transparent to the
client, as the session is sustained and a tunnel between Cisco Wireless LAN Controllers allows the client
to continue using the same DHCP- or client-assigned IP Address as long as the session remains active.
Note that the tunnel is torn down and the client must reauthenticate when the client sends a DHCP
Note: Cisco 1000 Series lightweight access points without a Primary, Secondary, and
Tertiary Cisco Wireless LAN Controllers assigned always search for a Master Cisco
Wireless LAN Controller first upon reboot. After adding Cisco 1000 Series lightweight
access points through the Master, assign Primary, Secondary, and Tertiary Cisco
Wireless LAN Controllers to each Cisco 1000 Series lightweight access point.
Cisco recommends that you disable the Master setting on all Cisco Wireless LAN
Controllers after initial configuration.
Because the Master Cisco Wireless LAN Controller is normally not used in a deployed
network, the Master setting is automatically disabled upon reboot or OS code
upgrade.