In various embodiments, methods and systems are provided for acquiring a mobile internet protocol address in a communication network. In an embodiment, a mobile network internet node key is sent to a service node. A mobile network internet node sends a mobile internet protocol access request message to an authentication node. The authentication node can then receive the mobile network internet node key transferred from the service node. In response to receiving a mobile internet protocol access accept message at the mobile network internet node transferred from the authentication node where the mobile internet protocol access accept message comprises the mobile network internet node key, the mobile internet protocol address is assigned at the mobile network internet node to a mobile station associated with a user identifier.