A network aware protocol for switching HTTP streams between devices

Pervasive multimedia enables delivery of content according to the user context. One interesting option addressed in this paper is uninterrupted delivery of the content to the dynamically changing most suitable device in the user proximity. We present a protocol for switching an HTTP stream to an alternative device connected through a different network. Streams can either be fetched from or pushed to the alternative device. The protocol estimates the connectivity of the new streaming device and adapts accordingly the content delivery. We address the assurance of the continuity of experience by introducing a hash verification technique providing an efficient way to synchronize the play-out from the “new” device with the “old” device. Using this protocol we have implemented on a Linux computer and Android smartphone a specific scenario supporting a short range (Bluetooth) communication between the new and old device and delivery over WLAN and UMTS. The evaluation examples verify proper functionality of the protocol which - in this set-up -achieves an inaccuracy of play out synchronization in the range of -10 to 50 ms.