Showing papers on "Multipath routing published in 2004"

Routing techniques in wireless sensor networks: a survey

Abstract: Wireless sensor networks consist of small nodes with sensing, computation, and wireless communications capabilities. Many routing, power management, and data dissemination protocols have been specifically designed for WSNs where energy awareness is an essential design issue. Routing protocols in WSNs might differ depending on the application and network architecture. In this article we present a survey of state-of-the-art routing techniques in WSNs. We first outline the design challenges for routing protocols in WSNs followed by a comprehensive survey of routing techniques. Overall, the routing techniques are classified into three categories based on the underlying network structure: flit, hierarchical, and location-based routing. Furthermore, these protocols can be classified into multipath-based, query-based, negotiation-based, QoS-based, and coherent-based depending on the protocol operation. We study the design trade-offs between energy and communication overhead savings in every routing paradigm. We also highlight the advantages and performance issues of each routing technique. The article concludes with possible future research areas.

Tapestry: a resilient global-scale overlay for service deployment

Abstract: We present Tapestry, a peer-to-peer overlay routing infrastructure offering efficient, scalable, location-independent routing of messages directly to nearby copies of an object or service using only localized resources. Tapestry supports a generic decentralized object location and routing applications programming interface using a self-repairing, soft-state-based routing layer. The paper presents the Tapestry architecture, algorithms, and implementation. It explores the behavior of a Tapestry deployment on PlanetLab, a global testbed of approximately 100 machines. Experimental results show that Tapestry exhibits stable behavior and performance as an overlay, despite the instability of the underlying network layers. Several widely distributed applications have been implemented on Tapestry, illustrating its utility as a deployment infrastructure.

Routing in a delay tolerant network

Abstract: We formulate the delay-tolerant networking routing problem, where messages are to be moved end-to-end across a connectivity graph that is time-varying but whose dynamics may be known in advance. The problem has the added constraints of finite buffers at each node and the general property that no contemporaneous end-to-end path may ever exist. This situation limits the applicability of traditional routing approaches that tend to treat outages as failures and seek to find an existing end-to-end path. We propose a framework for evaluating routing algorithms in such environments. We then develop several algorithms and use simulations to compare their performance with respect to the amount of knowledge they require about network topology. We find that, as expected, the algorithms using the least knowledge tend to perform poorly. We also find that with limited additional knowledge, far less than complete global knowledge, efficient algorithms can be constructed for routing in such environments. To the best of our knowledge this is the first such investigation of routing issues in DTNs.

Probabilistic Routing in intermittently connected networks

Abstract: In this paper, we address the problem of routing in intermittently connected networks. In such networks there is no guarantee that a fully connected path between source and destination exists at any time, rendering traditional routing protocols unable to deliver messages between hosts. There does, however, exist a number of scenarios where connectivity is intermittent, but where the possibility of communication still is desirable. Thus, there is a need for a way to route through networks with these properties. We propose PRoPHET, a probabilistic routing protocol for intermittently connected networks and compare it to the earlier presented Epidemic Routing protocol through simulations. We show that PRoPHET is able to deliver more messages than Epidemic Routing with a lower communication overhead.

Maximum lifetime routing in wireless sensor networks

Abstract: A routing problem in static wireless ad hoc networks is considered as it arises in a rapidly deployed, sensor based, monitoring system known as the wireless sensor network. Information obtained by the monitoring nodes needs to be routed to a set of designated gateway nodes. In these networks, every node is capable of sensing, data processing, and communication, and operates on its limited amount of battery energy consumed mostly in transmission and reception at its radio transceiver. If we assume that the transmitter power level can be adjusted to use the minimum energy required to reach the intended next hop receiver then the energy consumption rate per unit information transmission depends on the choice of the next hop node, i.e., the routing decision. We formulate the routing problem as a linear programming problem, where the objective is to maximize the network lifetime, which is equivalent to the time until the network partition due to battery outage. Two different models are considered for the information-generation processes. One assumes constant rates and the other assumes an arbitrary process. A shortest cost path routing algorithm is proposed which uses link costs that reflect both the communication energy consumption rates and the residual energy levels at the two end nodes. The algorithm is amenable to distributed implementation. Simulation results with both information-generation process models show that the proposed algorithm can achieve network lifetime that is very close to the optimal network lifetime obtained by solving the linear programming problem.

Comparison of routing metrics for static multi-hop wireless networks

Abstract: Routing protocols for wireless ad hoc networks have traditionally focused on finding paths with minimum hop count. However, such paths can include slow or lossy links, leading to poor throughput. A routing algorithm can select better paths by explicitly taking the quality of the wireless links into account. In this paper, we conduct a detailed, empirical evaluation of the performance of three link-quality metrics---ETX, per-hop RTT, and per-hop packet pair---and compare them against minimum hop count. We study these metrics using a DSR-based routing protocol running in a wireless testbed. We find that the ETX metric has the best performance when all nodes are stationary. We also find that the per-hop RTT and per-hop packet-pair metrics perform poorly due to self-interference. Interestingly, the hop-count metric outperforms all of the link-quality metrics in a scenario where the sender is mobile.

Approximate aggregation techniques for sensor databases

Abstract: In the emerging area of sensor-based systems, a significant challenge is to develop scalable, fault-tolerant methods to extract useful information from the data the sensors collect. An approach to this data management problem is the use of sensor database systems, exemplified by TinyDB and Cougar, which allow users to perform aggregation queries such as MIN, COUNT and AVG on a sensor network. Due to power and range constraints, centralized approaches are generally impractical, so most systems use in-network aggregation to reduce network traffic. However, these aggregation strategies become bandwidth-intensive when combined with the fault-tolerant, multipath routing methods often used in these environments. For example, duplicate-sensitive aggregates such as SUM cannot be computed exactly using substantially less bandwidth than explicit enumeration. To avoid this expense, we investigate the use of approximate in-network aggregation using small sketches. Our contributions are as follows: 1) we generalize well known duplicate-insensitive sketches for approximating COUNT to handle SUM, 2) we present and analyze methods for using sketches to produce accurate results with low communication and computation overhead, and 3) we present an extensive experimental validation of our methods.

DyAD - smart routing for networks-on-chip

Abstract: In this paper, we present and evaluate a novel routing scheme called DyAD which combines the advantages of both deterministic and adaptive routing schemes. More precisely, we envision a new routing technique which judiciously switches between deterministic and adaptive routing based on the network's congestion conditions. The simulation results show the effectiveness of DyAD by comparing it with purely deterministic and adaptive routing schemes under different traffic patterns. Moreover, a prototype router based on the DyAD idea has been designed and evaluated. Compared to purely adaptive routers, the overhead of implementing DyAD is negligible (less than 7%), while the performance is consistently better.

A routing scheme for content-based networking

Abstract: This work proposes a routing scheme for content-based networking. A content-based network is a communication network that features a new advanced communication model where messages are not given explicit destination addresses, and where the destinations of a message are determined by matching the content of the message against selection predicates declared by nodes. Routing in a content-based network amounts to propagating predicates and the necessary topological information in order to maintain loop-free and possibly minimal forwarding paths for messages. The routing scheme we propose uses a combination of a traditional broadcast protocol and a content-based routing protocol. We present the combined scheme and its requirements over the broadcast protocol. We then detail the content-based routing protocol, highlighting a set of optimization heuristics. We also present the results of our evaluation, showing that this routing scheme is effective and scalable.

A-STAR: A Mobile Ad Hoc Routing Strategy for Metropolis Vehicular Communications

Abstract: One of the major issues that affect the performance of Mobile Ad hoc NETworks (MANET) is routing. Recently, position-based routing for MANET is found to be a very promising routing strategy for inter-vehicular communication systems (IVCS). However, position-based routing for IVCS in a built-up city environment faces greater challenges because of potentially more uneven distribution of vehicular nodes, constrained mobility, and difficult signal reception due to radio obstacles such as high-rise buildings. This paper proposes a new position-based routing scheme called Anchor-based Street and Traffic Aware Routing (A-STAR), designed specifically for IVCS in a city environment. Unique to A-STAR is the usage of information on city bus routes to identify an anchor path with high connectivity for packet delivery. Along with a new recovery strategy for packets routed to a local maximum, the proposed protocol shows significant performance improvement in a comparative simulation study with other similar routing approaches.

Scenario-Based Planning for Partially Dynamic Vehicle Routing with Stochastic Customers

Abstract: The multiple vehicle routing problem with time windows (VRPTW) is a hard and extensively studied combinatorial optimization problem. This paper considers a dynamic VRPTW with stochastic customers, where the goal is to maximize the number of serviced customers. It presents a multiple scenario approach (MSA) that continuously generates routing plans for scenarios including known and future requests. Decisions during execution use a distinguished plan chosen, at each decision, by a consensus function. The approach was evaluated on vehicle routing problems adapted from the Solomon benchmarks with a degree of dynamism varying between 30% and 80%. They indicate that MSA exhibits dramatic improvements over approaches not exploiting stochastic information, that the use of consensus function improves the quality of the solutions significantly, and that the benefits of MSA increase with the (effective) degree of dynamism.

Minimum-energy multicast in mobile ad hoc networks using network coding

Abstract: The minimum energy required to transmit one bit of information through a network characterizes the most economical way to communicate in a network. In this paper, we show that, under a layered model of wireless networks, the minimum energy-per-bit for multicasting in a mobile ad hoc network can be found by a linear program; the minimum energy-per-bit can be attained by performing network coding. Compared with conventional routing solutions, network coding not only allows a potentially lower energy-per-bit to be achieved, but also enables the optimal solution to be found in polynomial time, in sharp contrast with the NP-hardness of constructing the minimum-energy multicast tree as the optimal routing solution. We further show that the minimum energy multicast formulation is equivalent to a cost minimization with linear edge-based pricing, where the edge prices are the energy-per-bits of the corresponding physical broadcast links. This paper also investigates minimum energy multicasting with routing. Due to the linearity of the pricing scheme, the minimum energy-per-bit for routing is achievable by using a single distribution tree. A characterization of the admissible rate region for routing with a single tree is presented. The minimum energy-per-bit for multicasting with routing is found by an integer linear program. We show that the relaxation of this integer linear program, studied earlier in the Steiner tree literature, can now be interpreted as the optimization for minimum energy multicasting with network coding. In short, this paper presents a unifying study of minimum energy multicasting with network coding and routing.

Source-location privacy in energy-constrained sensor network routing

Abstract: As sensor-driven applications become increasingly integrated into our lives, issues related to sensor privacy will become increasingly important. Although many privacy-related issues can be addressed by security mechanisms, one sensor network privacy issue that cannot be adequately addressed by network security is confidentiality of the source sensor's location. In this paper, we focus on protecting the source's location by introducing suitable modifications to sensor routing protocols to make it difficult for an adversary to backtrack to the origin of the sensor communication. In particular, we focus on the class of flooding protocols. While developing and evaluating our privacy-aware routing protocols, we jointly consider issues of location-privacy as well as the amount of energy consumed by the sensor network. Motivated by the observations, we propose a flexible routing strategy, known as phantom routing, which protects the source's location. Phantom routing is a two-stage routing scheme that first consists of a directed walk along a random direction, followed by routing from the phantom source to the sink. Our investigations have shown that phantom routing is a powerful technique for protecting the location of the source during sensor transmissions.

Efficient routing for peer-to-peer overlays

Abstract: Most current peer-to-peer lookup schemes keep a small amount of routing state per node, typically logarithmic in the number of overlay nodes. This design assumes that routing information at each member node must be kept small, so that the bookkeeping required to respond to system membership changes is also small, given that aggressive membership dynamics are expected. As a consequence, lookups have high latency as each lookup requires contacting several nodes in sequence. In this paper, we question these assumptions by presenting two peer-to-peer routing algorithms with small lookup paths. First, we present a one-hop routing scheme. We show how to disseminate information about membership changes quickly enough so that nodes maintain accurate routing tables with complete membership information. We also deduce analytic bandwidth requirements for our scheme that demonstrate its feasibility. We also propose a two-hop routing scheme for large scale systems of more than a few million nodes, where the bandwidth requirements of one-hop routing can become too large. This scheme keeps a fixed fraction of the total routing state on each node, chosen such that the first hop has low latency, and thus the additional delay is small. We validate our analytic model using simulation results that show that our algorithms can maintain routing information sufficiently up-to-date such that a large fraction (e.g., 99%) of the queries will succeed without being re-routed.

The impact of spatial correlation on routing with compression in wireless sensor networks

Abstract: The efficacy of data aggregation in sensor networks is a function of the degree of spatial correlation in the sensed phenomenon. While several data aggregation (i.e., routing with data compression) techniques have been proposed in the literature, an understanding of the performance of various data aggregation schemes across the range of spatial correlations is lacking. We analyze the performance of routing with compression in wireless sensor networks using an application-independent measure of data compression (an empirically obtained approximation for the joint entropy of sources as a function of the distance between them) to quantify the size of compressed information, and a bit-hop metric to quantify the total cost of joint routing with compression. Analytical modelling and simulations reveal that while the nature of optimal routing with compression does depend on the correlation level, surprisingly, there exists a practical static clustering scheme which can provide near-optimal performance for a wide range of spatial correlations. This result is of great practical significance as it shows that a simple cluster-based system design can perform as well as sophisticated adaptive schemes for joint routing and compression.

The case for separating routing from routers

Abstract: Over the past decade, the complexity of the Internet's routing infrastructure has increased dramatically. This complexity and the problems it causes stem not just from various new demands made of the routing infrastructure, but also from fundamental limitations in the ability of today's distributed infrastructure to scalably cope with new requirements.The limitations in today's routing system arise in large part from the fully distributed path-selection computation that the IP routers in an autonomous system (AS) must perform. To overcome this weakness, interdomain routing should be separated from today's IP routers, which should simply forward packets (for the most part). Instead, a separate Routing Control Platform (RCP) should select routes on behalf of the IP routers in each AS and exchange reachability information with other domains.Our position is that an approach like RCP is a good way of coping with complexity while being responsive to new demands and can lead to a routing system that is substantially easier to manage than today. We present a design overview of RCP based on three architectural principles path computation based on a consistent view of network state, controlled interactions between routing protocol layers, and expressive specification of routing policies and discuss the architectural strengths and weaknesses of our proposal.

Improving the reliability of internet paths with one-hop source routing

Abstract: Recent work has focused on increasing availability in the face of Internet path failures. To date, proposed solutions have relied on complex routing and path-monitoring schemes, trading scalability for availability among a relatively small set of hosts. This paper proposes a simple, scalable approach to recover from Internet path failures. Our contributions are threefold. First, we conduct a broad measurement study of Internet path failures on a collection of 3,153 Internet destinations consisting of popular Web servers, broad-band hosts, and randomly selected nodes. We monitored these destinations from 67 PlanetLab vantage points over a period of seven days, and found availabilities ranging from 99.6% for servers to 94.4% for broadband hosts. When failures do occur, many appear too close to the destination (e.g., last-hop and end-host failures) to be mitigated through alternative routing techniques of any kind. Second, we show that for the failures that can be addressed through routing, a simple, scalable technique, called one-hop source routing, can achieve close to the maximum benefit available with very low overhead. When a path failure occurs, our scheme attempts to recover from it by routing indirectly through a small set of randomly chosen intermediaries. Third, we implemented and deployed a prototype one-hop source routing infrastructure on PlanetLab. Over a three day period, we repeatedly fetched documents from 982 popular Internet Web servers and used one-hop source routing to attempt to route around the failures we observed. Our results show that our prototype successfully recovered from 56% of network failures. However, we also found a large number of server failures that cannot be addressed through alternative routing. Our research demonstrates that one-hop source routing is easy to implement, adds negligible overhead, and achieves close to the maximum benefit available to indirect routing schemes, without the need for path monitoring, history, or a-priori knowledge of any kind.

Maximum lifetime routing in wireless ad-hoc networks

Abstract: Routing problems in mobile ad-hoc networks (MANET) have been receiving increasing attention in the last few years. Most of the proposed routing protocols concentrate on finding and maintaining routes in the face of changing topology caused by mobility or other environmental changes. More recently, power-aware routing protocols and topology control algorithms have been developed to address the issue of limited energy reserve of the nodes in ad-hoc networks. We consider the routing problem in MANET with the goal of maximizing the life time of the network. We propose a distributed routing algorithm that reaches the optimal (centralized) solution to within an asymptotically small relative error. Our approach is based on the formulation of multicommodity flow, and it allows to consider different power consumption models and bandwidth constraints. It works for both static and slowly changing dynamic networks.

Load balancing in ad hoc networks: single-path routing vs. multi-path routing

Abstract: Multi-path routing has been studied thoroughly in the context of wired networks. Ii has been shown that using multiple paths to route messages between any source-destination pair of nodes (instead of using a single path) balances the load more evenly throughout the network. The common belief is that the same is true for ad hoc networks, i.e., multi-path routing balances the load significantly better than single-path routing. We show that this is not necessarily the case. We introduce a new model for evaluating the load balance under multi-path routing, when the paths chosen are the first K shortest paths (for a pre-specified K). Using this model, we show that unless we use a very large number of paths (which is very costly and therefore infeasible) the load distribution is almost the same as single shortest path routing. This is in contrary to the previous existing results which assume that multi-path routing distributes the load uniformly.

Communication Networking: An Analytical Approach

Abstract: The viewpoint is that communication networking is about efficient resource sharing. The focus is on the three building blocks of communication networking, namely, multiplexing, switching and routing. The approach is analytical, with the discussion being driven by mathematical analyses of and solutions to specific engineering problems. The result? A comprehensive, effectively organized treatment of core engineering issues in communication networking. Written for both the networking professional and for the classroom, this book covers fundamental concepts in detail and places design issues in context by drawing on real world examples from current technologies. ·Systematically uses mathematical models and analyses to drive the development of a practical understanding of core network engineering problems. ·Provides in-depth coverage of many current topics, including network calculus with deterministically-constrained traffic, congestion control for elastic traffic, packet switch queuing, switching architectures, virtual path routing, and routing for quality of service. ·Includes over 200 hands-on exercises and class-tested problems, dozens of schematic figures, a review of key mathematical concepts, and a glossary.

SPREAD: enhancing data confidentiality in mobile ad hoc networks

Abstract: Security is a critical issue in a mobile ad hoc network (MANET). We propose and investigate a novel scheme, security protocol for reliable data delivery (SPREAD), to enhance the data confidentiality service in a mobile ad hoc network. The proposed SPREAD scheme aims to provide further protection to secret messages from being compromised (or eavesdropped) when they are delivered across the insecure network. The basic idea is to transform a secret message into multiple shares by secret sharing schemes and then deliver the shares via multiple independent paths to the destination so that even if a small number of nodes that are used to relay the message shares are compromised, the secret message as a whole is not compromised. We present the overall system architecture and investigate the major design issues. We first describe how to obtain message shares using the secret sharing schemes. Then we study the appropriate choice of the secret sharing schemes and the optimal allocation of the message shares onto each path in order to maximize the security. The results show that the SPREAD is more secure and also provides a certain degree of reliability without sacrificing the security. Thirdly, the multipath routing techniques are discussed and the path set optimization algorithm is developed to find the multiple paths with the desired property, i.e., the overall path set providing maximum security. Finally, we present the simulation results to justify the feasibility and evaluate the effectiveness of SPREAD.

Improved routing strategies for Internet traffic delivery.

Abstract: We analyze different strategies aimed at optimizing routing policies in the Internet. We first show that for a simple deterministic algorithm the local properties of the network deeply influence the time needed for packet delivery between two arbitrarily chosen nodes. We next rely on a real Internet map at the autonomous system level and introduce a score function that allows us to examine different routing protocols and their efficiency in traffic handling and packet delivery. Our results suggest that actual mechanisms are not the most efficient and that they can be integrated in a more general, though not too complex, scheme.

Independent zone routing: an adaptive hybrid routing framework for ad hoc wireless networks

Abstract: To effectively support communication in such a dynamic networking environment as the ad hoc networks, the routing framework has to be adaptable to the spatial and temporal changes in the characteristics of the network, such as traffic and mobility patterns. Multiscoping, as is provided through the concept of the Zone Routing Protocol (ZRP) for example, can serve as a basis for such an adaptive behavior. The Zone Routing framework implements hybrid routing by every network node proactively maintaining routing information about its local neighborhood called the routing zone, while reactively acquiring routes to destinations beyond the routing zone. In this paper, we propose the Independent Zone Routing (IZR) framework, an enhancement of the Zone Routing framework, which allows adaptive and distributed configuration for the optimal size of each node's routing zone, on the per-node basis. We demonstrate that the performance of IZR is significantly improved by its ability to automatically and dynamically tune the network routing operation, so as to flexibly and robustly support changes in the network characteristics and operational conditions. As a point of reference, through this form of adaptation, we show that the volume of routing control traffic overhead in the network can be reduced by an order of magnitude, under some set of parameter values. Furthermore, the adaptive nature of IZR enhances the scalability of these networks as well.

Routing in Space and Time in Networks with Predictable Mobility

Abstract: We consider the problem of routing in emerging wireless networks where nodes move around explicitly carrying messages to facilitate communication in an otherwise partitioned network. The absence of a path at any instant of time between a source and destination makes the traditional mobile ad hoc routing protocols unsuitable for these networks. However, the explicit node movements create paths “over time” that include the possibility of a node carrying a message before forwarding to another suitable node. Identifying such paths over space and time is a key challenge in these store, carry and forward networks. In most of these networks, the mobility of nodes is predictable either over a finite time horizon or indefinitely due to periodicity in node motion. We propose a new space-time routing framework for these networks leveraging the predictability in node motion. Specifically, we construct space-time routing tables where the next hop node is selected from the current as well as the future neighbors. Unlike traditional routing tables, our space-time routing tables use both the destination and the arrival time of message to determine the next hop node. We devise an algorithm to compute these spacetime routing tables to minimize the end-to-end message delivery delay. Our routing algorithm is based on a space-time graph model derived from the mobility of nodes. We empirically evaluate our approach using simulations and observe improved performance as compared to other approaches based on heuristics.

Optimizing cost and performance for multihoming

Abstract: Multihoming is often used by large enterprises and stub ISPs to connect to the Internet. In this paper, we design a series of novel smart routing algorithms to optimize cost and performance for multihomed users. We evaluate our algorithms through both analysis and extensive simulations based on realistic charging models, traffic demands, performance data, and network topologies. Our results suggest that these algorithms are very effective in minimizing cost and at the same time improving performance. We further examine the equilibrium performance of smart routing in a global setting and show that a smart routing user can improve its performance without adversely affecting other users.

Routing design in operational networks: a look from the inside

Abstract: In any IP network, routing protocols provide the intelligence that takes a collection of physical links and transforms them into a network that enables packets to travel from one host to another. Though routing design is arguably the single most important design task for large IP networks, there has been very little systematic investigation into how routing protocols are actually used in production networks to implement the goals of network architects. We have developed a methodology for reverse engineering a coherent global view of a network's routing design from the static analysis of dumps of the local configuration state of each router. Starting with a set of 8,035 configuration files, we have applied this method to 31 production networks. In this paper we present a detailed examination of how routing protocols are used in operational networks. In particular, the results show the conventional model of "interior" and "exterior" gateway protocols is insufficient to describe the diverse set of mechanisms used by architects, and we provide examples of the more unusual designs and examine their trade-offs. We discuss the strengths and weaknesses of our methodology, and argue that it opens paths towards new understandings of network behavior and design.

Analysis of multipath Routing-Part I: the effect on the packet delivery ratio

Abstract: In this paper, we develop an analytical framework for evaluating multipath routing in mobile ad hoc networks. The instability of the topology (e.g., failure of links) in this type of network due to nodal mobility and changes in wireless propagation conditions makes transmission of time-sensitive information a challenging problem. To combat the inherent unreliability of these networks, we propose a routing scheme that uses multiple paths simultaneously by splitting the information between a multitude of paths, so as to increase the probability that the essential portion of the information is received at the destination without incurring excessive delay. Our scheme works by adding an overhead to each packet, which is calculated as a linear function of the original packet bits. The resulting packet (information and overhead) is fragmented into smaller blocks and distributed over the available paths. The probability of reconstructing the original information at the destination is derived in an analytical form and its behavior is studied for some special cases. It is shown that, under certain constraints, the packet dropping probability decreases as the number of used paths is increased.

System and method for dynamic distributed communication

Abstract: Growth of a distributed communication system is facilitated through dynamic addition of routing elements. A new routing element may be added to a network of routing elements by first establishing a connection between the new routing element and an existing routing element in the network. The connection may be either wireless or wireline. At least one address is assigned to the new routing element. Each assigned address comes from a pool of addresses maintained at the existing routing element. At least one pool of addresses is issued to the new routing element, permitting the new routing element to dynamically add yet another new routing element to the network of routing elements.

On the effect of localization errors on geographic face routing in sensor networks

Abstract: In the absence of location errors, geographic routing - using a combination of greedy forwarding and face routing - has been shown to work correctly and efficiently. The effects of location errors on geographic routing have not been studied before. In this work we provide a detailed analysis of the effects of location errors on the correctness and performance of geographic routing in static sensor networks. First, we perform a micro-level behavioral analysis to identify the possible protocol error scenarios and their conditions and bounds. Then, we present results from an extensive simulation study of GPSR and GHT to quantify the performance degradation due to location errors. Our results show that even small location errors (of 10% of the radio range or less) can in fact lead to incorrect (non-recoverable) geographic routing with noticeable performance degradation. We then introduce a simple modification for face routing that eliminates probable errors and leads to near perfect performance.

SDAR: a secure distributed anonymous routing protocol for wireless and mobile ad hoc networks

Abstract: Providing security and privacy in mobile ad hoc networks has been a major issue over the last few years. Most research work has so far focused on providing security for routing and data content, but nothing has been done in regard to providing privacy and anonymity over these networks. We propose a novel distributed routing protocol which guarantees security, anonymity and high reliability of the established route in a hostile environment, such as an ad hoc wireless network, by encrypting the routing packet header and abstaining from using unreliable intermediate nodes. The major objective of our protocol is to allow trustworthy intermediate nodes to participate in the path construction protocol without jeopardizing the anonymity of the communicating nodes. We describe our protocol, SDAR (secure distributed anonymous routing), and provide its proof of correctness.