  This paper presents EmbJXTAChord, a novel peer-to-peer (P2P) architecture
that integrates the good features of different sources, such as JXTA, EXI,
CoAP, combining and augmenting them to provide a framework that is specifically
devised for developing IoT applications over heterogeneous networks.
EmbJXTAChord provides for several interesting properties, such as, distributed
and fault-tolerant resource discovery, transparent routing over subnetworks,
application protocol independence from the transport protocol in narrowband
WSN, thus eliminating the need for using dedicated software or configuring
custom gateways to achieve these functionalities. Moreover, EmbJXTAChord offers
native support not only for TCP/HTTP, but also for Bluetooth RFCOMM and
6LoWPAN, thus opening to a broad range of IoT devices in supernetworks composed
of networks using different interconnection technologies, not necessarily
IP-based. In addition, EmbJXTAChord offers security over heterogeneous networks
providing support for secure peergroups (even nested) and for group encryption,
thus allowing for unicast and multicast communication between groups of objects
sharing the same resources. Finally, EmbJXTAChord provides jxCOAP-E, a new CoAP
implementation that leverages on the transport mechanisms for heterogeneous
networks offered by EmbJXTAChord. jxCOAP-E enables to realize a RESTful service
architecture for peer-to-peer narrowband or broadband networks composed of
devices connected via Ethernet, Wi-Fi, Bluetooth, BLE or IEEE 802.15.4.
Differently from CoAP, jxCOAP-E provides a distributed and fault-tolerant
service discovery mechanism and support for secure multicast communications.
The paper presents EmbJXTAChord, discusses all the relevant design challenges
and presents a comparative experimental performance assessment with
state-of-the-art solutions on commercial-off-the-shelf devices.
