Overview Of Mobility Groups - Cisco 2100 Series Configuration Manual

Chapter 12 Configuring Mobility GroupsWireless Device Access

Overview of Mobility Groups

Overview of Mobility Groups
A mobility group is a set of controllers, identified by the same mobility group name, that defines the
realm of seamless roaming for wireless clients. By creating a mobility group, you can enable multiple
controllers in a network to dynamically share information and forward data traffic when inter-controller
or inter-subnet roaming occurs. Controllers in the same mobility group can share the context and state
of client devices as well as their list of access points so that they do not consider each other's access
points as rogue devices. With this information, the network can support inter-controller wireless LAN
roaming and controller redundancy. Figure 12-4 shows an example of a mobility group.
Controllers do not have to be of the same model to be a member of a mobility group. Mobility groups
Note
can be comprised of any combination of controller platforms.
Figure 12-4 A Single Mobility Group
As shown above, each controller is configured with a list of the other members of the mobility group.
Whenever a new client joins a controller, the controller sends out a unicast message to all of the
controllers in the mobility group. The controller to which the client was previously connected passes on
the status of the client. All mobility message exchanges between controllers are carried out using UDP
packets on port 16666.
Controller software release 5.1 or later supports up to 24 controllers in a single mobility group. The
number of access points supported in a mobility group is bound by the number of controllers and
controller types in the group.
Cisco Wireless LAN Controller Configuration Guide
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