A computing device having communications framework for a protocol stack. The framework includes a number of layers, each layer representing a layer in a protocol stack. At each layer, a protocol is a bearer of an upper adjacent layer. Each layer is arranged to monitor the availability of one or more alternate bearer layers below. Where there is more than one alternate bearer layer below, a layer is said to be mobile. In the event of a new bearer layer becoming available at a mobile layer, a decision is made as to whether or not to migrate to that bearer layer based on established policies in the mobile layer and, optionally, on communication with higher layers or with the client application. If the decision to migrate is positive, the mobile layer then ensures establishment of the new bearer layer and initiates and completes migration to it. The client of a connection active over the connection stack need not be disturbed by mobility events within the stack providing the connection.