Opportunistic networks use unpredictable and time-limited contacts to disseminate data. Therefore, it is important that protocols transfer the most relevant data when contacts do occur. I talk about our insights from Haggle, a system for opportunistic content sharing, focusing on how search can be leveraged for relevance aware dissemination. Unlike other mobile content sharing systems, Haggle prioritises content based on how relevant it is to users, and allows highly desirable content to propagate faster than less desirable content.

I also highlight the opportunities arising from multi-node contacts. Multi-Node contacts encounters warrant a more holistic view of routing decisions, where more factors than just the features of a message-node tuple can be considered. We discuss these aspects and propose a protocol addition to leverage multi-contact opportunities with the notion of heterogeneous link quality, in order to limit energy consumption.

Christian Rohner is professor in Computer Systems at Uppsala University. His research interests include system aspects in mobile opportunistic networks, energy efficiency in networked embedded systems, and wireless security. He has been the lead of the Haggle architecture. Christian has a PhD in computer science and a diploma in electrical engineering, both from ETH Zürich.