Showing papers on "Hazy Sighted Link State Routing Protocol published in 2000"

Performance comparison of two on-demand routing protocols for ad hoc networks

Abstract: Ad hoc networks are characterized by multi-hop wireless connectivity, frequently changing network topology and the need for efficient dynamic routing protocols. We compare the performance of two prominent on-demand routing protocols for mobile ad hoc networks - dynamic source routing (DSR) and ad hoc on-demand distance vector routing (AODV). A detailed simulation model with MAC and physical layer models is used to study inter-layer interactions and their performance implications. We demonstrate that even though DSR and AODV share a similar on-demand behavior the differences in the protocol mechanics can lead to significant performance differentials. The performance differentials are analyzed using varying network load, mobility and network size. Based on the observations, we make recommendations about how the performance of either protocol can be improved.

Location-aided routing (LAR) in mobile ad hoc networks

Abstract: A mobile ad hoc network consists of wireless hosts that may move often. Movement of hosts results in a change in routes, requiring some mechanism for determining new routes. Several routing protocols have already been proposed for ad hoc networks. This paper suggests an approach to utilize location information (for instance, obtained using the global positioning system) to improve performance of routing protocols for ad hoc networks. By using location information, the proposed Location‐Aided Routing (LAR) protocols limit the search for a new route to a smaller “request zone” of the ad hoc network. This results in a significant reduction in the number of routing messages. We present two algorithms to determine the request zone, and also suggest potential optimizations to our algorithms.

AODV-BR: backup routing in ad hoc networks

Abstract: Nodes in mobile ad hoc networks communicate with one another via packet radios on wireless multihop links. Because of node mobility and power limitations, the network topology changes frequently. Routing protocols therefore play an important role in mobile multihop network communications. A trend in ad hoc network routing is the reactive on-demand philosophy where routes are established only when required. Most of the protocols in this category, however, use a single route and do not utilize multiple alternate paths. We propose a scheme to improve existing on-demand routing protocols by creating a mesh and providing multiple alternate routes. Our algorithm establishes the mesh and multipaths without transmitting any extra control message. We apply our scheme to the Ad-hoc On-Demand Distance Vector (AODV) protocol and evaluate the performance improvements by simulation.

Fisheye state routing: a routing scheme for ad hoc wireless networks

Abstract: This paper presents a novel routing protocol for wireless ad hoc networks-fisheye state routing (FSR). FSR introduces the notion of multi-level fisheye scope to reduce routing update overhead in large networks. Nodes exchange link state entries with their neighbors with a frequency which depends on distance to destination. From link state entries, nodes construct the topology map of the entire network and compute optimal routes. Simulation experiments show that FSR is a simple, efficient and scalable routing solution in a mobile, ad hoc environment.

Power-aware localized routing in wireless networks

Abstract: Two metrics where transmission power depends on distance between nodes, and a cost aware metric based on remaining battery power at nodes (assuming constant transmission power), together with corresponding non-localized shortest path routing algorithms, were recently proposed. We define a new power-cost metric based on the combination of both node's lifetime and distance based power metrics. We then propose power, cost, and power-cost GPS based localized routing algorithms, where nodes make routing decisions solely on the basis of location of their neighbors and destination. Power aware localized routing algorithm attempts to minimize the total power needed to route a message between a source and a destination. Cost-aware localized algorithm is aimed at extending battery's worst case lifetime. The combined power-cost algorithm attempts to minimize the total power needed and to avoid nodes with short remaining lifetime. We prove that these localized power, cost, and power-cost efficient routing algorithms are loop-free.

Multipath source routing in wireless ad hoc networks

Abstract: We propose a new multipath routing protocol for ad hoc wireless networks-multipath source routing (MSR), which is based on DSR (dynamic source routing). MSR extends DSR's route discovery and route maintenance mechanism to deal with multipath routing. Based on the measurement of RTT, we propose a scheme to distribute load between multiple paths. The simulation results show that our approach improves the throughput of TCP and UDP and the packet delivery ratio, and reduces the end-to-end delay and the queue size, while adding little overhead. As a result, MSR decreases the network congestion quite well.

An implementation study of the AODV routing protocol

Abstract: The Ad hoc On-Demand Distance Vector (AODV) routing protocol is designed for use in ad hoc mobile networks. Because of the difficulty of testing an ad hoc routing protocol in a real-world environment, a simulation was first created so that the protocol design could be tested in a variety of scenarios. Once simulation of the protocol was nearly complete, the simulation was used as the basis for an implementation in the Linux operating system. In the course of converting the simulation into an implementation, certain modifications were needed in AODV and the Linux kernel due to both simplifications made in the simulation of AODV and to incompatibilities of the Linux kernel and the IP-layer to routing in a mobile environment. This paper details many of the changes that were necessary during the development of the implementation.

Method and apparatus for controlling communication links between network nodes to reduce communication protocol overhead traffic

Abstract: Link-State Advertisement (LSA) and other routing control packets are transmitted within a wireless communication system or network via selective enablement of control links for transference of the packets between network nodes Specifically, an exemplary wireless network includes a plurality of nodes arranged into clusters with each cluster having cluster member nodes and a designated cluster head node The present invention selectively reduces the quantity of control links between head nodes to transmit the LSA and other routing control packets with reduced protocol overhead traffic, thereby permitting the network to utilize link-state based protocols effectively (eg, with minimal impact on network throughput) while expanding to larger scales

Route-lifetime assessment based routing (RABR) protocol for mobile ad-hoc networks

Abstract: Owing to the absence of any static support structure, ad-hoc networks are prone to link failures. The 'shortest path seeking' routing protocols may not lead to stable routes. The consequent route failures that ensue, lead to the degradation of system throughput. This paper suggests a routing protocol wherein the route selection is done on the basis of an intelligent residual lifetime assessment of the candidate routes. Schemes for performance enhancement with TCP and non-TCP traffic in ad-hoc networks are proposed. The protocol is backed by simulations in ns that show excellent adaptation to increasing network mobility. We have also introduced new route cache management and power aware data transmission schemes.

Scalable unidirectional routing with zone routing protocol (ZRP) extensions for mobile ad-hoc networks

Abstract: Ad-hoc networks consist of peer-to-peer communicating nodes that are highly mobile. As such, an ad-hoc network lacks infrastructure and the topology of the network changes dynamically. The task of routing data from a source to a destination in such a network is challenging. Several routing protocols have been proposed for wireless ad-hoc networks. Most of these protocols, however, pre-suppose the presence of bi-directional links between the nodes in the network. In reality the ad-hoc network may consist of heterogeneous nodes with different power capabilities and hence, different transmission ranges. When this is the case, a given node might be able to receive the transmission of another given node but might not be able to successfully transmit to the latter. Thus, unidirectional links are formed. Most of the current routing protocols are unsuitable for deployment when such unidirectional links are present. We consider a routing protocol called the zone routing protocol (ZRP) that has been proposed for wireless ad-hoc networks with bi-directional links. The zone routing protocol employs a hybrid proactive (table driven) and reactive (on-demand) methodology to provide scalable routing in the ad-hoc network. However, in the presence of unidirectional links some routes remain undiscovered if ZRP is used. We propose extensions to ZRP to support its deployment when unidirectional links are present. In particular, we propose a query enhancement mechanism that recursively builds partial routes to a destination. Simulation results show that even at a high mobility of 20 m/s, the queries resulting due to the enhancement mechanism result in the computation of valid routes more than 80% of the time. These results are valid even when a large number (40% of nodes have half the transmission range as that of the remaining nodes) of unidirectional links are present in the network.

Landmark routing for large ad hoc wireless networks

Abstract: We present an enhanced version of the routing protocol, Landmark Ad Hoc Routing (LANMAR). LANMAR combines the features of Fisheye State Routing (FSR) and Landmark routing. The enhanced version features landmark election to cope with the dynamic and mobile environment. Other advantages of LANMAR include the use of landmarks for each logical group (e.g., a team of co-workers at a convention or a tank battalion in the battlefield) in order to reduce routing update overhead in large networks, and the exchanging of neighborhood link state only with neighbors. When the network size grows, remote groups of nodes are "summarized" by the corresponding landmarks. As a result, each node will maintain accurate routing information about immediate neighborhood; at the same time it will keep track of the routing directions to the landmark nodes and thus, to remote groups. Simulation experiments show that the enhanced version suffers some performance degradation at steady state because of election overhead. However, it still provides an efficient and scalable routing solution in a mobile, ad hoc environment. Moreover, the election provides a much needed recovery from landmark failures.

Depth first search and location based localized routing and QoS routing in wireless networks

Abstract: In a localized routing algorithm, node A currently holding the message forwards it based on the location of itself, its neighboring nodes and destination. We propose to use depth first search (DFS) method for routing decisions. Each node A, upon receiving the message for the first time, sorts all its neighbors according to a criteria such as their distance to destination and uses that order in DFS algorithm. It is the first localized algorithm that guarantees delivery for (connected) wireless networks modeled by arbitrary graphs, including inaccurate location information. We then propose the first localized QoS routing algorithm for wireless networks. It performs DFS routing algorithm after edges with insufficient bandwidth or insufficient connection time are deleted from the graph, and attempts to minimize hop count. This is also the first paper to apply GPS in QoS routing decisions, and to consider the connection time (estimated lifetime of a link) as a QoS criterion. The average length of measured QoS path in our experiments, obtained by DFS method, was between 1 and 1.34 times longer than the length of QoS path obtained by shortest path algorithm. The overhead is considerably reduced by applying the concept of internal nodes.

Routing stability in congested networks: experimentation and analysis

Abstract: Loss of the routing protocol messages due to network congestion can cause peering session failures in routers, leading to route flaps and routing instabilities. We study the effects of traffic overload on routing protocols by quantifying the stability and robustness properties of two common Internet routing protocols, OSPF and BGP, when the routing control traffic is not isolated from data traffic. We develop analytical models to quantify the effect of congestion on the robustness of OSPF and BGP as a function of the traffic overload factor, queueing delays, and packet sizes. We perform extensive measurements in an experimental network of routers to validate the analytical results. Subsequently we use the analytical framework to investigate the effect of factors that are difficult to incorporate into an experimental setup, such as a wide range of link propagation delays and packet dropping policies. Our results show that increased queueing and propagation delays adversely affect BGP's resilience to congestion, in spite of its use of a reliable transport protocol. Our findings demonstrate the importance of selective treatment of routing protocol messages from other traffic, by using scheduling and utilizing buffer management policies in the routers, to achieve stable and robust network operation.

A comparison of on-demand and table driven routing for ad-hoc wireless networks

Abstract: We introduce WRP-Lite, which is a table-driven routing protocol that uses non-optimal routes, and compare its performance with the performance of the dynamic source routing (DSR) protocol, which is an on-demand routing protocol for wireless ad-hoc networks. We evaluate the performance of WRP-Lite and DSR for varying degree of mobility and traffic in a 20-node network. The performance parameters are end-to-end delay, control overhead, percentage of packets delivered, and hop distribution. We show that WRP-Lite has much better delay and hop performance while having comparable overhead to DSR.

The effects of MAC protocols on ad hoc network communication

Abstract: As mobile computing gains popularity, the need for ad hoc routing protocols will continue to grow. There have been numerous simulations comparing the performance of these protocols under varying conditions and constraints. One question that arises is whether the choice of MAC protocol affects the relative performance of the routing protocols being studied. This paper investigates the answer to that question by simulating the performance of three ad hoc routing protocols when run over different MAC protocols. It is determined that the choice of MAC layer protocol does, in fact, affect the relative performance of the routing protocols.

On distributed, geographic-based packet routing for LEO satellite networks

Abstract: Advances in satellite technology are enabling the deployment of large constellations of low Earth Orbiting (LEO) satellites. Next-generation systems will be tailored for broadband, packet-switched services, and therefore require either distributed or centralized packet routing mechanisms. Some researchers have hypothesized that the semi-regular mesh topology of a polar-orbiting constellation admits a simple distributed routing protocol based on using geographic information embedded in the node address. We take a closer look at this hypothesis in the context of commercially-proposed constellation designs. Using simulation, we study a distributed routing protocol that selects the next hop based on a minimization of the remaining distance to the destination. Our numerical results indicate that this routing strategy usually yields good routes, with an average latency degradation of less than 10 ms when compared with the optimal route. However, there are locations in the topology, most notably around the counter-rotating seams, the polar regions, and close to the destination of a packet, where the assumption of a regular mesh topology breaks down and it is difficult to guarantee robustness without adding significant additional complexity to the protocol.

A novel routing algorithm for ad hoc networks

Abstract: A mobile ad hoc network (MANET) is comprised of mobile hosts that can communicate with two other using wireless links. In this paper we present a novel routing algorithm called GPSAL (GPS/ant-like routing algorithm) which is based on GPS (Global Positioning System) and mobile software agents modeled on ants for routing in ad hoc networks. We compare our algorithm to the location-aided routing (LAR) algorithm for MANET which is also based on GPS. Simulation results show that our algorithm has less overhead than LAR.

Methods and systems for providing message translation, accounting and routing service in a multi-protocol communications network environment

Abstract: A network element that is capable facilitating the routing and accounting of messages between a plurality of network elements that do not share a common signaling application protocol nor a common transport protocol suite. In one embodiment of the present invention, a Multi-Protocol Gateway (MPG) is adapted to receive a signaling message and subsequently translate both the signaling and transport protocol suite prior to message routing. The MPG node is also configured to create and maintain usage and measurements data that may subsequently be used to produce billing records.

A GPS/ant-like routing algorithm for ad hoc networks

Abstract: A mobile ad hoc network (MANET) is comprised of mobile hosts that can communicate with each other using wireless links. In this paper we present a novel routing algorithm called GPSAL (GPS/ant-like routing algorithm) which is based on the GPS (Global Positioning System) and mobile software agents modeled on ants for routing in ad hoc networks. We compare our algorithm to the location-aided routing (LAR) (Ko and Vaidya 1998) algorithm for MANET which is also based on GPS. Simulation results show that our algorithm has less overhead than LAR.

Experimental evaluation of a wireless ad hoc network

Abstract: We experimentally evaluate the performance of a wireless ad hoc network from the point of view of both the routing and transport layers. The experiments are done on a testbed with desktop PCs and laptops using wireless radio LAN interfaces. For these experiments an on-demand routing protocol called AODV (ad hoc on-demand distance vector) has been implemented as a part of the operating system protocol stack. We describe our design choices and the experimental setup. The performance evaluation reveals that the performance is poor beyond two hops at moderate to high loads.

Improving the Up*/Down* Routing Scheme for Networks of Workstations

Abstract: Networks of workstations (NOWs) are being considered as a cost-effective alternative to parallel computers. Many NOWs are arranged as a switch-based network with irregular topology, which makes routing and deadlock avoidance quite complicated. Current proposals use the up*/down* routing algorithm to remove cyclic dependencies between channels and avoid deadlock. Recently, a simple and effective methodology to compute up*/down* routing tables has been proposed by us. The resulting up*/down* routing scheme makes use of a different link direction assignment to compute routing tables. Assignment of link direction is based on generating an underlying acyclic connected graph from the network graph. In this paper, we propose and evaluate new heuristic rules to compute the underlying graph. Moreover, we propose a traffic balancing algorithm to obtain more efficient up*/down* routing tables when source routing is used. Evaluation results show that the routing algorithm based on the new methodology increases throughput by a factor of up to 2.8 in large networks, also reducing latency significantly.

A routing algorithm for connection-oriented low earth orbit (LEO) satellite networks with dynamic connectivity

Abstract: Low Earth Orbit lLEOr satellites move with respect to a fixed observer on the Earth surface. Satellites in the polar regions and the seam switch off their intersatellite links to the neighbor satellites. As a result, the connectivity pattern of the network changes. Ongoing calls passing through these links need to be rerouted. A large number of simultaneous rerouting attempts would cause excessive signaling load in the network. Moreover, the handover calls could be blocked because of the insufficient network resources in the newly established routes or large connection redestablishment delay. In this paper, a routing protocol is introduced to reduce the number of routing attempts resulting from link connectivity change. The protocol does not use the links that will be switched off before the connection is over. Since the call durations are not known a priori, the proposed protocol utilizes a probabilistic approach. The performance of the protocol is evaluated through simulation experiments. The experimental results indicate that the routing protocol reduces the number of rerouting attempts resulting from connectivity changes of the network.

Active routing for ad hoc networks

Abstract: Ad hoc networks are wireless multihop networks whose highly volatile topology makes the design and operation of a standard routing protocol hard. With an active networking approach, one can define and deploy routing logic at runtime in order to adapt to special circumstances and requirements. We have implemented several active ad hoc routing protocols that configure the forwarding behavior of mobile nodes, allowing data packets to be efficiently routed between any two nodes of the wireless network. Isolating a simple forwarding layer in terms of both implementation and performance enables us to stream delay-sensitive audio data over the ad hoc network. In the control plane, active packets permanently monitor the connectivity and setup, and modify the routing state.

An on-demand QoS routing protocol for mobile ad hoc networks

Abstract: We propose a on-demand bandwidth routing protocol for QoS (quality of service) support in mobile ad hoc networks. The QoS routing feature is important for a mobile network to interconnect wired networks with QoS support (e.g., ATM, Internet, etc.). The QoS routing protocol can also work in a stand-alone mobile ad hoc network for real-time applications. Under such a routing protocol, the source (or the ATM gateway) is informed of the bandwidth and QoS available to any destination in the mobile network. This knowledge enables the establishment of QoS connections within the mobile network and the efficient support of real time applications. In addition, it enables more efficient call admission control. In case of ATM interconnection, the bandwidth information can be used to carry out intelligent handoff between ATM gateways and/or to extend the ATM virtual circuit service to the mobile network with possible renegotiation of QoS parameters at the gateway. Simulation results suggest distinct performance advantages of our protocol calculating the bandwidth information. It is particularly useful in call admission control. Furthermore, "on-demand" routing enhances the performance in the mobile environment because the source can keep more connectivity to a receiver in the path-finding duration. Simulation experiments show this improvement.

Techniques for intrusion-resistant ad hoc routing algorithms (TIARA)

Abstract: This paper presents a set of design techniques, collectively called TIARA (Techniques for Intrusion-resistant Ad Hoc Routing Algorithms), to protect ad hoc networks against denial of service attacks. The TIARA mechanisms described seek to limit the damage sustained by ad hoc networks from intrusion attacks and allow for continued network operation at an acceptable level during such attacks. These mechanisms are designed to handle attacks on the routing traffic as well as the data traffic in ad hoc networks thereby providing a comprehensive defense against intruders. TIARA is routing algorithm independent. That is, TIARA may be viewed as providing general design principles and techniques the can be incorporated within a number of existing ad hoc routing algorithms to make them robust to intrusion attacks.

On-demand QoS-based routing protocol for ad hoc mobile wireless networks

Abstract: To explore QoS issue for ad hoc mobile wireless networks is not trivial because of the high mobility of mobile nodes. Based an the DSDV (destination-sequenced distance-vector) routing protocol for maintaining up-to-date route information, previous works on QoS routing for ad hoc mobile wireless networks do require adding an extra bandwidth for exchanging QoS information. However the size and the update frequency of the routing table are increased tremendously with the number of mobile nodes. We propose an on-demand-based QoS routing protocol to achieve the QoS requirement. The goal of this paper is to discover an optimal route with minimum time delay for transmitting real-time data from a source node hop by hop to a destination node under some predefined constraints.

Stochastic routing in ad hoc wireless networks

Abstract: We investigate a network routing problem where a probabilistic local broadcast model for wireless transmission is used. We present results showing that an index policy is optimal for this problem. We extend the original model to allow for power control, and assert that the index nature of the optimal routing policy remains unchanged. We further allow time-varying system parameters in the original model, and discover conditions under which a time-varying index routing policy is optimal. Finally, we present a distributed implementation of the routing policy and provide results on its convergence properties.

Alternate path routing in mobile ad hoc networks

Abstract: This research used a custom event-driven network simulator to evaluate alternate path routing's (APR's) behavior in mobile ad hoc networks (MANETs) In particular, it investigated how much route-diversity is inherent in typical ad-hoc networks, and the ability of a globally reactive routing-protocol (such as the zone routing protocol) to capture and utilize that route diversity It then explored the end-to-end capacity improvements provided by APR Results indicate that APR's benefit is highly dependent on both the network topology and the channel access methods

Routing protocols overview and design issues for self-organized network

Abstract: A self-organized network is a kind of wireless network that can be deployed instantly and provide easy network communication without the support of pre-established network infrastructures, such as base stations. This network architecture brings promise of much better mobility and communication capacity. Various routing protocols have been presented. This paper gives a detailed study of whether each of them works and whether there is a superior one that can function successfully under all kinds of situations. We conclude that there is no superior protocol for all situations and look at the main issues to be considered when designing routing protocols for a self-organized network.