A system and method for a hierarchical distributed control architecture to support roaming wireless client devices. Access switches serve one or more Internet Protocol (IP) subnets that include plural IP addresses. The access switches are arranged in switch peer groups and store information about other access switches in that switch peer group and about locations of wireless client devices that are associated with any access switch in the switch peer group. The access switches are further grouped into a corresponding mobility sub-domain each including plural switch peer groups. Plural controller devices control access switches in a corresponding mobility sub-domain. Each controller device stores information about the access switches and about locations of wireless client devices within its mobility sub-domain. A central controller device communicates with the controller devices for the respective mobility sub-domains. The central controller device stores information about locations of wireless client devices in the mobility sub-domains.