A method and system for handling roaming mobile nodes in a wireless network. The system uses a Subnet Context Manager to store current Network session keys, security policy and duration of the session (e.g. session timeout) for mobile nodes, which is established when the mobile node is initially authenticated. Pairwise transit keys are derived from the network session key. The Subnet Context Manager handles subsequent reassociation requests. When a mobile node roams to a new access point, the access point obtains the network session key from the Subnet Context Manager and validates the mobile node by computing a new pairwise transient key from the network session key.