Anycast is a new communication service defined in IPv6 (Internet Protocol Version 6) [6]. An anycast message is the one that should be delivered to the 'nearest' member in a group of designated recipients. The ¡¥nearest¡¦ is not always the ¡¥best¡¦ member. In this paper, we propose a routing protocol for anycast message. It is composed of two subprotocols: the routing table establishment subprotocol and the packet forwarding subprotocol. In the routing table establishment subprotocol, we propose a mininum delay path method (MDP). We get a minimum delay path from router to destination by MDP. In the packet forwarding protocol, we propose a minimum delay and load balancing method (MDLB). We dispatch traffic load to a server with minimum delay and light load by MDLB. The performance has demonstrated the benefits of MDP and MDLB in reducing end-to-end delay and increasing throughput of network.

In ad hoc network, one needs other nodes to relay data packets. But resources in each node are limited. Therefore, these nodes may not relay other¡¦s data packet without getting any benefit. In this paper, a routing path selecting algorithm based on price mechanism is proposed. It helps nodes to get some benefits by relaying others¡¦ data packets. Moreover, the algorithm we proposed selects a routing path with less payment and more resources. Simulation results show that the drop rate, block rate and the cost of routing paths are reduced compared to the competing algorithms.

Bluetooth is a low-cost, low-power and short-range wireless communication technology, which operates in the global unlicensed 2.4GHz ISM band. Recently many people have paid close attention to do a lot of relevant research and product development on it. In addition to the scatternet formation problem, two major issues of Bluetooth, scheduling and routing, also greatly interest the researchers. In this paper, we propose new scatternet topology architecture for Bluetooth networks, called multi-ring scatternet. The scatternet formation and packet routing method are presented. The self-routing property of multi-ring scatternet makes its routing method efficient and low overhead. Comparing to the Bluetree scatternet, the proposed scatternet is more reliable and relieves the bottleneck at root nodes. As compared with the BlueRing scatternet, it reduces the network diameter and average routing path. The simulation results reveal that our multi-ring scatternet topology gains better performance by the three metrics of number of piconets, average routing path length and throughput.

With rapidly development of wireless network technology in the past few years, hand-held devices can connect to Internet everywhere conveniently by equipped with wireless card. IEEE 802.11 defined two types of wireless networks: infrastructure networks and ad hoc networks. Since ad hoc networks are a kind of networks without access points, efficient routing is an important issue for these networks. A more efficient routing approach involves dividing the network into several clusters by using a clustering algorithm. The purpose of this paper is to investigate a hybrid cluster routing algorithm in mobile ad hoc networks. This investigation proposed a double-manager K-hop clustering algorithm based on the link evaluation. This algorithm not only can elect a more suitable node as the cluster head but also can reduce the overhead of the managers. Furthermore, this study devised maintenance and backup mechanisms to stabilize network performance in the face of network topology changes. The simulation results demonstrate that our proposed algorithm outperforms other clustering algorithm in terms of number of clusters, routing overhead of managers and cluster stability.

When the number of nodes increases, the chance that nodes or links fail increases. Then a fault-tolerant routing method is important to maintian the performance of the system. In the hypercube, safety levels and safety vectors provide the fault distribution information used to guide routing fault-tolerantly. The safety vectors for the hypercube describes the fault distribution more percisely than the safety level. The concept of safety levels has been applied to the star graph by other researchers. In this thesis, we apply the concept of the safety vectors in the hypercube to the star graph, and define three different safety vectors, including undirected safety vector, directed safety vector, and statistical safety vector. We first show the ability of the undirected safety vector. Then we extend the ideal to the directed safety vector and show it is better in deciding routing paths than the safety level for the star graph. We also show the reason that makes the directed safety vector not able to be used for derouting. In the previous result, a little change can make the directed safety vector usable for derouting in the hypercube. However, for the star graph, we can use only the information of neighbors to perform derouting with a slight modification in the directed safety vector. Then we set levels to the routing ability using the statistical safety vector. Try to make it contain more information of the fault distribution.

In an ad hoc networks, it is an important problem about how to increase the bandwidth utilization and guarantee Quality-of-Service. In order to increase the bandwidth utilization under the situation of limited bandwidth, we want to achieve the target by using the bitty residual bandwidth in the ad hoc networks. Hence we integrate several single paths into a multi-path that satisfies QoS requirement. In this paper, we present a policy to look up, maintain, and reroute the virtual circuit in the ad hoc networks. From the result of simulation, we obtain that our proposal indeed can increase the bandwidth utilization of ad hoc networks. But the condition of splitting also increases the overhead of connection, and affects the forced terminated ratio and packets lost ratio under mobility.

The purpose of this research is to present the design and development of a routing system, custom developed for a fence manufacturing company in the continental US. The objective of the routing module of the system is to generate least cost routes from the home-center of the company to a set of delivery locations. Routes are evolved for a set of customer locations based on the sales order information and are frequently modified to include rush orders. These routes are such that each delivery is made within a given time window. Further, total truckload of all delivery locations over any particular route is not allowed to exceed the weight and volume capacities of the truck. The basic system modules such as user interface functions and database are designed using MS Access 2000. An interface module to retrieve data from existing ERP system of the company is developed to import pick-ticket information. A customer inter-distance maintenance module is designed with the abilities of a learning tool to reduce information retrieval time between the routing system and the GIS server. The Graphical User Interface with various screen forms and printable reports is developed along with the routing module to achieve complete system functionality and to provide an efficient logistics solution. This problem, formulated as a mixed-integer program, is of particular interest due to its generality to model problem scenarios in the production shop such as job-shop scheduling, material handling, etc. This problem is coded and solved for instances with different input parameters using AMPL/CPLEX. Results of test runs for the company data show that the solution time increases exponentially with the number of customers. Hence, a heuristic approach is developed and implemented. Sample runs with small instances are solved for optimality using AMPL/CPLEX and are used to compare the performance of the heuristics. However, test runs solved using the heuristics for larger instances are compared with the manual routing costs. The comparison shows a considerable cost savings for heuristic solutions. Further, a what-if analysis module is implemented to aid the dispatcher in choosing input parameters based on sensitivity analysis. In conclusion, further improvement of the routing system and future research directions are proposed.

Recent advances in low-power technologies have resulted in the proliferation of inexpensive handheld mobile computing devices. Soon, just like the Internet empow- ered a whole new world of applications for personal computers, the development and deployment of robust ubiquitous wireless networks will enable many new and exciting futuristic applications. Certain to be an important part of this future is a class of networks known as "mobile ad hoc networks." Mobile ad hoc networks (or simply "ad hoc networks") are local-area networks formed "on the spot" between collocated wireless devices. These devices self-organize by sharing information with their neigh- bors to establish communication pathways whenever and wherever they are. For ad hoc networks to succeed, however, new protocols must be developed that are capable of adapting to their dynamic nature. In this dissertation, we present a number of adaptive protocols that are designed for this purpose. We investigate new link layer mechanisms that dynamically monitor and adapt to changes in link quality, including a protocol that uses common control messages to form a tight feedback control loop for adaptation of the link data rate to best match the channel conditions perceived by the receiver. We also investigate routing protocols that adapt route selection according to network characteristics. In particular, we present two on-demand routing protocols that are designed to take advantage of the presence of multirate links. We then investigate the performance of TCP, showing how communication outages caused by link failures and routing delays can be very detrimental to its performance. In response, we present a solution to this problem that uses explicit feedback messages from the link layer about link failures to adapt TCP's behavior. Finally, we show how link failures in heterogeneous networks containing links with widely varying bandwidth and delay can cause repeated "modal" changes in capacity that TCP is slow to detect. We then present a modifed version of TCP that is capable of more rapidly detecting and adapting to these changes.

This study presents the development of a cell-based routing model. The model developed is a two parameter hydrological routing model that uses a coarse resolution stream network to route runoff from each cell in the watershed to the outlet. The watershed is divided into a number of equal cells, which are approximated as cascade of linear reservoirs or tanks. Water is routed from a cell downstream, depending on the flow direction of the cell, using the cascade of tanks. The routing model consists of two phases, first is the overland flow routing, which is followed by the channel flow routing. In this study, the cell-to-cell stream flow routing model is applied to the Brazos River Basin to demonstrate the impact of the cascade of tanks on the flow over a simple linear reservoir method. This watershed was tested with a uniform runoff depth in absence of observed runoff data. A case study on Waller Creek in Austin, Texas with observed runoff depths and stream flow is used to demonstrate the calibration and validation of model parameters.

Wireless sensor networks consist of hundreds to thousands of low-power multifunctioning sensor nodes, operating in an unattended environment, with limited computational and sensing capabilities. Since the sensor nodes are equipped with small, often irreplaceable, batteries with limited power capacity, it is essential that the network be energy efficient in order to maximize the life span of the network. Hierarchical routing is an efficient way to lower energy consumption within a cluster, performing data aggregation and fusion.Within a clustering organization, intra-cluster communication can be single hop or multihop, as well as inter-cluster communication. Multihop communication between a data source and a data sink is usually more energy efficient than direct transmission because of the characteristics of wireless channel. However, the hot-spots problem arises when using the multihop forwarding model in inter-cluster communication. Because the cluster heads closer to the data sink are burdened with heavy relay traffic, they will die much faster than the other cluster heads. This paper presents an cluster-based routing protocol named An Adjustable Load Balancing Cluster-based Routing for Wireless Sensor Networks(ALBAC).The aim of the work is to let the cluster size be small nearby base station because cluster heads closer to the base station need relay more data.We wnat to let every cluster heads consume same energy. Simulation results show that our unequal clustering mechanism clearly improves the network lifetime over LEACH and BCDCP.