In the last few years we have seen an explosion in the number of notebook computers and in the growth of the Internet. Mobile users expect to access the Internet's information resources and to communicate with other Internet users. The concept of Mobile IP is proposed to satisfy these demands. Using the base Mobile IP protocol, all datagrams destined for a mobile node are routed through that mobile node's home agent, which intercepts and tunnels each datagram to the mobile node's current location. This tunneling scheme creates a triangle routing problem, causing packets to travel through the home agent. In this paper, we propose that a Proxy Home Router (PHR) for routing performance improvement in a Mobile IP environment. One or more of Intermediate Systems (IS) on the route path between the correspondent node (CN) and the home agent (HA) are established as a PHR which then delivers packet instead of the home agent (HA). This PHR route optimization (PHR-RO) scheme has the following features. It is compatible with the base Mobile IP with existing Internet computers, and applications. Also, it is unnecessary for a CN to be modified in the proposed architecture. We also define Route Optimization messages in order to optimize route to a mobile node. Using these protocol extensions, a PHR may cache the binding information of a mobile node, and then tunnel their datagrams for the mobile node (MN) directly to the care-of address (CoA), bypassing the mobile node's home agent (HA). To analyze the performance of our PHR route optimization (PHR-RO) scheme, we propose a simulation model and show how to improve routing performance. Through this performance analysis, we conclude that the route optimization with a proxy home router (PHR) has better performance in terms of the end-to-end delay and TCP throughput.

In this paper, the problem of Redundant Duplicated RREQ Network-wide Flooding (RDRNF), induced by multiple sensor nodes during route discovery in event-driven wireless sensor networks, is described. In order to reduce the number of signaling messages during the route discovery phase, a novel extension, named the Localized Route Discovery Extension (LRDE), to the on-demand ad hoc routing protocol, is proposed. The LRDE reduces energy consumption during route discovery. The heuristically and temporarily selected Path Set-up Coordinator (PSC) plays the role of a route request broker that alleviates redundant route request flooding. The LRDE also sets a route path be aggregation-compatible. The PSC can effectively perform data aggregation through the routing path constructed by the LRDE. The simulation results reveal that significant energy is conserved by reducing signaling overhead and performing data aggregation when LRDE is applied to on-demand routing protocols.