Handover and Resource Management of Mobile Nodes with Unidirectional Links

Mobile nodes with unidirectional network interfaces are not considered as a special case in the standardisation of mobile IPv6. For the integration of unidirectional broadcast technologies, such as DVB-H and DVB-T, into mobile IPv6 environment with heterogeneous access networks, there is a need to support the handover and QoS requirements of mobile services using unidirectional access networks. In this paper, scenarios for handover of mobile nodes with unidirectional links are analysed. In the different use cases, mobile services using downstream unidirectional connections for reception and upstream channels for return connectivity based on additional wireless access networks are described. For seamless service continuation, when mobile nodes moves to access networks with unidirectional links, the interaction of the link layer tunnelling mechanisms (RFC 3077) with the mobile IPv6 and fast handovers protocol is discussed. The idea is to allow the obtaining of the IP tunnel address for the emulation of return path before the handover happens. The QoS management for unidirectional access networks is proposed based on QoS brokers reserving resources separately for the downstream and upstream links. To support mobile services using unidirectional networks, QoS information base describing also capabilities of return channels is taken into consideration.