Patent ID: 8428006

Claim:
A system comprising: a plurality of access switches configured to serve one or more Internet Protocol (IP) subnets that comprises a plurality of IP addresses, the plurality of access switches arranged in switch peer groups such that each access switch within a given switch peer group is configured to store information about other access switches in that switch peer group and about locations of wireless client devices that are associated with any wireless access point on any access switch in the switch peer group, the plurality of access switches being further grouped into a corresponding one of a plurality of mobility sub-domains each comprising a plurality of switch peer groups; a plurality of controller devices each configured to control access switches in a corresponding mobility sub-domain, each controller device storing information about the plurality of access switches within its mobility sub-domain and about locations of wireless client devices at access switches in its mobility sub-domain; and a central controller device configured to communicate with the plurality of controller devices for the respective mobility sub-domains, the central controller device configured to store information about locations of wireless client devices in the mobility sub-domains, wherein when a particular wireless client device roams from a first mobility sub-domain to a second mobility sub-domain, the controller device assigned to the second mobility sub-domain forwards an announce message from the particular wireless client device to an access switch of the first mobility sub-domain where the particular wireless client device was most previously attached, and wherein the access switch that receives the announce message forwarded by the controller device sends a handoff message to a particular access switch in the second mobility sub-domain where the particular wireless client device is currently located, wherein the handoff message contains context for the particular wireless client device and other client policies associated with the particular wireless client device.