With the growth of different design goals and application requirements, wireless sensor networks (WSNs) have been increasingly popular for a wide variety of purposes, e.g., image formation of a target field, intrusion detection, surveillance and environmental monitoring. In this paper, a multi-hop heterogeneous cluster-based optimization algorithm (MHCOA) for WSNs is proposed. The motivation to MHCOA for WSNs is that several higher energy sensor nodes act as cluster heads, which are deployed artificially, while some low energy sensor nodes act as cluster members, which are deployed randomly. In order to realize monitoring task, we complete three major works in this paper. First, MHCOA calculates the number of cluster heads and communication radius of low energy sensor nodes; Second, it finishes monitoring task through data packets transmission with higher energy nodes acting as cluster heads in the form of multi-hop heterogeneous WSNs; Finally, simulation results show that compared to its peers in heterogeneous WSNs, MHCOA reduces the number of cluster heads, which saves the network average energy by up to 16.7 % and extends the network life by up to 38 %, while with less end-to-end delay.

In recent years, Vehicular Ad Hoc Networks (VANET)

IP multicast and MPLS (multi-protocol label switching) are proposed to support emerging network applications effectively, extending current IP routing and switching mode in different ways. It is still in progress to combine IP multicast with MPLS properly. In this paper, a novel architecture, called Rendezvous MPLS Multicast, is proposed to support IP multicast in MPLS networks and to have the scalability of multicast routing, to achieve the label space reduction, and to solve some practical problems in implementation. A two-layered structure of control plane without multicast routing protocols is implemented by overlaying novel service control plane over the existing routing control plane to support multicast state aggregate. The interface between the two planes is formulated to support the interaction and cooperation. Moreover, the label distribution process for MPLS P2MP (point to multi-point) connection, with RSVP-TE (resource reservation protocol-traffic engineering) protocol, is extended to support aggregate of multiple label switching paths with traffic engineering and guarantee of quality of service. An algorithm of selecting Rendezvous Routers for Rendezvous MPLS Multicast has been presented. A test-bed with Linux-based implementations of MPLS multicast router and IP multicast service control system has also been constructed. The experimental results show its efficiency in terms of label space reduction and multicast traffic balancing, with the whole system adapting to the dynamic change of group members and network topology.

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