A Disruption Tolerant Mobility Architecture Towards Convergent Terminal Mobility

In recent years, a lot of terminal mobility support schemes have been proposed. These schemes mainly focus on providing seamless mobility by reducing the handover delay. They work well when the handover takes place between two overlapping wireless networks. However, in some worst scenario, it is possible that a Mobile Node (MN) becomes disconnected from the network for some time before it can join another wireless network. In such case, existing mobility protocols will suffer great data loss and the data connection could break. The inability to preserve data connection across long handover delay or connectivity disruption is an unavoidable obstacle before a convergent terminal mobility can be achieved. In this paper, we propose a Disruption Tolerant Mobility Architecture (DTMA) to address this issue. In DTMA, terminal mobility is supported via the use of local proxy server. User applications communicate with other hosts via the local proxy on the mobile node itself. To enable disruption tolerance, DTMA adapts Delay Tolerant Network (DTN) architecture as a transport protocol. When the node is disconnected from the network, data sent to it will be cached by the network and delivered to the node later when it reconnects to the network. The traffic overhead of DTMA is analyzed and it is shown that DTMA provides disruption tolerance with acceptable traffic overhead.