Mobility in a Protocol Stack

In a protocol stack comprising communication framework (CF) Application Programming Interfaces (API's, 403), transport protocols 404 (eg. TCP), network protocols 405 (eg. IP), link protocols 406 (eg. WiFi , GPRS), and hardware bearers 409 (eg. a WiFi adapter), mobility is achieved by allowing each layer to monitor the availability of the layers below and migrate to a new bearer layer according to policies or decisions from higher layers, leaving the overall connection undisturbed. Mobility is thus provided at any layer, rather than solely at the link layer (eg. switching between and WiFi and GPRS upon leaving a hotspot as in the Generic Access Network). The Communications Framework 401 is split into three CF planes 410-412; each arranged to handle decisions ("management" 412), stack-building/dismantling ("control" 411) and data transport ("data" 410) respectively according to the established protocols, with the protocol layers separated into a number of CF Protocol nodes (404a-406d), each of which can communicate with adjacent nodes in any of 4 directions.