Mid Sweden University

Sensor have been playing an important role and been useful for society, organizations and even for humans. The things around us that we use in our daily life such as sensors attached to people, smart devices, vehicles and mobile phones can be integrated by using sensor values. This thesis concerns the implementation of NAT penetration techniques in the SensibleThings platform. The SensibleThings open source platform which apply the advantage of peer-to-peer (P2P) networking, developed by Mid Sweden University. An algorithm for NAT penetration was proposed, but there was no implementation and evaluation showed there was a need for a new technique. However, this new algorithm tries to use direct connection, UPnP configuration or NAT hole-punching techniques, to communicate between peers and if unsuccessful will use a relay as a fallback. This paper explores different NAT types. There are mainly four NAT types; what separates them is different filtering and mapping algorithms. The objective of this study is to provide seamless NAT traversal and gain scalability. The implementation showed that both UPnP and hole punching techniques are successful to bridge the gap across NAT. It leads to the conclusion that UPnP and hole-punching is approximately 300 milliseconds and 100 milliseconds better respectively than the existing proxy communication. However, UPnP is only suitable for small network areas as it uses multicast in its communication. It allows the client to control only one NAT device and because of security issues it is not preferred by large organization. The hole-punching technique failed in implementing a symmetric NAT type, thus the current proxy solution is used to handle the problem. Finally, this paper presents future work to improve the system and measure scalability.

Keywords: P2P, NAT, SensibleThings, UPnP, hole punching.