Showing papers on "Wireless Routing Protocol published in 2005"
01 May 2005
TL;DR: The three main categories explored in this paper are data-centric, hierarchical and location-based; each routing protocol is described and discussed under the appropriate category.
Abstract: Recent advances in wireless sensor networks have led to many new protocols specifically designed for sensor networks where energy awareness is an essential consideration. Most of the attention, however, has been given to the routing protocols since they might differ depending on the application and network architecture. This paper surveys recent routing protocols for sensor networks and presents a classification for the various approaches pursued. The three main categories explored in this paper are data-centric, hierarchical and location-based. Each routing protocol is described and discussed under the appropriate category. Moreover, protocols using contemporary methodologies such as network flow and quality of service modeling are also discussed. The paper concludes with open research issues. � 2003 Elsevier B.V. All rights reserved.
3,573 citations
22 Aug 2005
TL;DR: A new routing scheme, called Spray and Wait, that "sprays" a number of copies into the network, and then "waits" till one of these nodes meets the destination, which outperforms all existing schemes with respect to both average message delivery delay and number of transmissions per message delivered.
Abstract: Intermittently connected mobile networks are sparse wireless networks where most of the time there does not exist a complete path from the source to the destination. These networks fall into the general category of Delay Tolerant Networks. There are many real networks that follow this paradigm, for example, wildlife tracking sensor networks, military networks, inter-planetary networks, etc. In this context, conventional routing schemes would fail.To deal with such networks researchers have suggested to use flooding-based routing schemes. While flooding-based schemes have a high probability of delivery, they waste a lot of energy and suffer from severe contention, which can significantly degrade their performance. Furthermore, proposed efforts to significantly reduce the overhead of flooding-based schemes have often be plagued by large delays. With this in mind, we introduce a new routing scheme, called Spray and Wait, that "sprays" a number of copies into the network, and then "waits" till one of these nodes meets the destination.Using theory and simulations we show that Spray and Wait outperforms all existing schemes with respect to both average message delivery delay and number of transmissions per message delivered; its overall performance is close to the optimal scheme. Furthermore, it is highly scalable retaining good performance under a large range of scenarios, unlike other schemes. Finally, it is simple to implement and to optimize in order to achieve given performance goals in practice.
2,712 citations
TL;DR: A detailed investigation of current state-of-the-art protocols and algorithms for WMNs is presented and open research issues in all protocol layers are discussed to spark new research interests in this field.
Abstract: Wireless mesh networks (WMNs) have emerged as a key technology for next-generation wireless networking. Because of their advantages over other wireless networks, WMNs are undergoing rapid progress and inspiring numerous applications. However, many technical issues still exist in this field. In order to provide a better understanding of the research challenges of WMNs, this article presents a detailed investigation of current state-of-the-art protocols and algorithms for WMNs. Open research issues in all protocol layers are also discussed, with an objective to spark new research interests in this field.
1,785 citations
TL;DR: This paper presents attacks against routing in ad hoc networks, and the design and performance evaluation of a new secure on-demand ad hoc network routing protocol, called Ariadne, which prevents attackers or compromised nodes from tampering with uncompromising routes consisting of uncompromised nodes.
Abstract: An ad hoc network is a group of wireless mobile computers (or nodes), in which individual nodes cooperate by forwarding packets for each other to allow nodes to communicate beyond direct wireless transmission range. Prior research in ad hoc networking has generally studied the routing problem in a non-adversarial setting, assuming a trusted environment. In this paper, we present attacks against routing in ad hoc networks, and we present the design and performance evaluation of a new secure on-demand ad hoc network routing protocol, called Ariadne. Ariadne prevents attackers or compromised nodes from tampering with uncompromised routes consisting of uncompromised nodes, and also prevents many types of Denial-of-Service attacks. In addition, Ariadne is efficient, using only highly efficient symmetric cryptographic primitives.
1,230 citations
13 Mar 2005
TL;DR: This paper suggests that the base station be mobile; in this way, the nodes located close to it change over time and the obtained improvement in terms of network lifetime is in the order of 500%.
Abstract: Although many energy efficient/conserving routing protocols have been proposed for wireless sensor networks, the concentration of data traffic towards a small number of base stations remains a major threat to the network lifetime. The main reason is that the sensor nodes located near a base station have to relay data for a large part of the network and thus deplete their batteries very quickly. The solution we propose in this paper suggests that the base station be mobile; in this way, the nodes located close to it change over time. Data collection protocols can then be optimized by taking both base station mobility and multi-hop routing into account. We first study the former, and conclude that the best mobility strategy consists in following the periphery of the network (we assume that the sensors are deployed within a circle). We then consider jointly mobility and routing algorithms in this case, and show that a better routing strategy uses a combination of round routes and short paths. We provide a detailed analytical model for each of our statements, and corroborate it with simulation results. We show that the obtained improvement in terms of network lifetime is in the order of 500%.
937 citations
TL;DR: The threat model for ad hoc routing is formulated and several specific attacks that can target the operation of a protocol are presented that can provide the basis for future research in this rapidly evolving area.
Abstract: In this paper we present a survey of secure ad hoc routing protocols for mobile wireless networks. A mobile ad hoc network is a collection of nodes that is connected through a wireless medium forming rapidly changing topologies. The widely accepted existing routing protocols designed to accommodate the needs of such self-organized networks do not address possible threats aiming at the disruption of the protocol itself. The assumption of a trusted environment is not one that can be realistically expected; hence several efforts have been made towards the design of a secure and robust routing protocol for ad hoc networks. We briefly present the most popular protocols that follow the table-driven and the source-initiated on-demand approaches. Based on this discussion we then formulate the threat model for ad hoc routing and present several specific attacks that can target the operation of a protocol. In order to analyze the proposed secure ad hoc routing protocols in a structured way we have classified them into five categories; solutions based on asymmetric cryptography, solutions based on symmetric cryptography, hybrid solutions, reputation-based solutions and a category of add-on mechanisms that satisfy specific security requirements. A comparison between these solutions can provide the basis for future research in this rapidly evolving area.
807 citations
27 Aug 2005
TL;DR: An analysis of energy efficient routing protocols with direct communication protocol and a novel energy conscious cluster head selection algorithm for making system more reliable and efficient are presented.
Abstract: The paper presents an analysis of energy efficient routing protocols with direct communication protocol. A comparison of these protocols is made analyzing energy consumption at each node and explaining system lifetime after certain rounds. The paper also proposes a novel energy conscious cluster head selection algorithm for making system more reliable and efficient. Simulation shows that our proposed algorithm enhances the system reliability and accuracy.
646 citations
25 May 2005
TL;DR: This paper formally defines and presents an effective heuristic for the minimum INterference Survivable Topology Control (INSTC) problem which seeks a channel assignment for the given network such that the induced network topology is interference-minimum among all K-connected topologies.
Abstract: The throughput of wireless networks can be significantly improved by multi-channel communications compared with single-channel communications since the use of multiple channels can reduce interference influence. In this paper, we study interference-aware topology control and QoS routing in IEEE 802.11-based multi-channel wireless mesh networks with dynamic traffic. Channel assignment and routing are two basic issues in such networks. Different channel assignments can lead to different network topologies. We present a novel definition of co-channel interference. Based on this concept, we formally define and present an effective heuristic for the minimum INterference Survivable Topology Control (INSTC) problem which seeks a channel assignment for the given network such that the induced network topology is interference-minimum among all K-connected topologies. We then formulate the Bandwidth-Aware Routing (BAR) problem for a given network topology, which seeks routes for QoS connection requests with bandwidth requirements. We present a polynomial time optimal algorithm to solve the BAR problem under the assumption that traffic demands are splittable. For the non-splittable case, we present a maximum bottleneck capacity path routing heuristic. Simulation results show that compared with the simple common channel assignment and shortest path routing approach, our scheme improves the system performance by 57% on average in terms of connection blocking ratio.
546 citations
TL;DR: This work proposes a QoS-aware routing protocol that incorporates an admission control scheme and a feedback scheme to meet the QoS requirements of real-time applications and implements these schemes by using two bandwidth estimation methods to find the residual bandwidth available at each node to support new streams.
Abstract: Routing protocols for mobile ad hoc networks (MANETs) have been explored extensively in recent years. Much of this work is targeted at finding a feasible route from a source to a destination without considering current network traffic or application requirements. Therefore, the network may easily become overloaded with too much traffic and the application has no way to improve its performance under a given network traffic condition. While this may be acceptable for data transfer, many real-time applications require quality-of-service (QoS) support from the network. We believe that such QoS support can be achieved by either finding a route to satisfy the application requirements or offering network feedback to the application when the requirements cannot be met. We propose a QoS-aware routing protocol that incorporates an admission control scheme and a feedback scheme to meet the QoS requirements of real-time applications. The novel part of this QoS-aware routing protocol is the use of the approximate bandwidth estimation to react to network traffic. Our approach implements these schemes by using two bandwidth estimation methods to find the residual bandwidth available at each node to support new streams. We simulate our QoS-aware routing protocol for nodes running the IEEE 802.11 medium access control. Results of our experiments show that the packet delivery ratio increases greatly, and packet delay and energy dissipation decrease significantly, while the overall end-to-end throughput is not impacted, compared with routing protocols that do not provide QoS support.
510 citations
Proceedings Article•
01 Dec 2005TL;DR: This paper first analyzes the possible types of routing protocols that can be used and shows that proactive hop-by-hop routing protocols are the most appropriate for mesh networks, and studies several existing routing metrics, including hop count, ETX, ETT, WCETT and MIC.
Abstract: Designing routing metrics is critical for performance in wireless mesh networks. The unique characteristics of mesh networks, such as static nodes and the shared nature of the wireless medium, invalidate existing solutions from both wired and wireless networks and impose unique requirements on designing routing metrics for mesh networks. In this paper, we focus on identifying these requirements. We first analyze the possible types of routing protocols that can be used and show that proactive hop-by-hop routing protocols are the most appropriate for mesh networks. Then, we examine the requirements for designing routing metrics according to the characteristics of mesh networks and the type of routing protocols used. Finally, we study several existing routing metrics, including hop count, ETX, ETT, WCETT and MIC in terms of their ability to satisfy these requirements. Our simulation results of the performance of these metrics confirm our analysis of these metrics.
468 citations
13 Jun 2005
TL;DR: This work presents the context-aware routing (CAR) algorithm, a novel approach to the provision of asynchronous communication in partially-connected mobile ad hoc networks, based on the intelligent placement of messages.
Abstract: The vast majority of mobile ad hoc networking research makes a very large assumption - that communication can only take place between nodes that are simultaneously accessible within the same connected cloud (i.e., that communication is synchronous). In reality, this assumption is likely to be a poor one, particularly for sparsely or irregularly populated environments. We present the context-aware routing (CAR) algorithm. CAR is a novel approach to the provision of asynchronous communication in partially-connected mobile ad hoc networks, based on the intelligent placement of messages. We discuss the details of the algorithm, and then present simulation results demonstrating that it is possible for nodes to exploit context information in making local decisions that lead to good delivery ratios and latencies with small overheads.
05 Dec 2005
TL;DR: This paper presents the MoVe algorithm, which uses velocity information to make intelligent opportunistic forwarding decisions, which provides a reasonable trade-off between resource overhead and performance.
Abstract: When highly mobile nodes are interconnected via wireless links, the resulting network can be used as a transit network to connect other disjoint ad-hoc networks. In this paper, we compare five different opportunistic forwarding schemes, which vary in their overhead, their success rate, and the amount of knowledge about neighboring nodes that they require. In particular, we present the MoVe algorithm, which uses velocity information to make intelligent opportunistic forwarding decisions. Using auxiliary information to make forwarding decisions provides a reasonable trade-off between resource overhead and performance.
02 May 2005
TL;DR: Cross-Link Detection Protocol (CLDP) as discussed by the authors enables provably correct geographic routing on arbitrary connectivity graphs, which is not only correct but practical: it incurs low overhead, exhibits low path stretch, always succeeds in real, static wireless networks, and converges quickly after topology changes.
Abstract: Geographic routing has been widely hailed as the most promising approach to generally scalable wireless routing. However, the correctness of all currently proposed geographic routing algorithms relies on idealized assumptions about radios and their resulting connectivity graphs. We use testbed measurements to show that these idealized assumptions are grossly violated by real radios, and that these violations cause persistent failures in geographic routing, even on static topologies. Having identified this problem, we then fix it by proposing the Cross-Link Detection Protocol (CLDP), which enables provably correct geographic routing on arbitrary connectivity graphs. We confirm in simulation and further testbed measurements that CLDP is not only correct but practical: it incurs low overhead, exhibits low path stretch, always succeeds in real, static wireless networks, and converges quickly after topology changes.
TL;DR: This paper describes and evaluates ARAN and shows that it is able to effectively and efficiently discover secure routes within an ad hoc network, and details how ARAN can secure routing in environments where nodes are authorized to participate but untrusted to cooperate, as well as environments where participants do not need to be authorization to participate.
Abstract: Initial work in ad hoc routing has considered only the problem of providing efficient mechanisms for finding paths in very dynamic networks, without considering security. Because of this, there are a number of attacks that can be used to manipulate the routing in an ad hoc network. In this paper, we describe these threats, specifically showing their effects on ad hoc on-demand distance vector and dynamic source routing. Our protocol, named authenticated routing for ad hoc networks (ARAN), uses public-key cryptographic mechanisms to defeat all identified attacks. We detail how ARAN can secure routing in environments where nodes are authorized to participate but untrusted to cooperate, as well as environments where participants do not need to be authorized to participate. Through both simulation and experimentation with our publicly available implementation, we characterize and evaluate ARAN and show that it is able to effectively and efficiently discover secure routes within an ad hoc network.
22 Aug 2005
TL;DR: A metric that estimates the average waiting time for each potential next hop is designed, which provides performance similar to that of schemes that have global knowledge of the network topology, yet without requiring that knowledge.
Abstract: Delay-tolerant networks (DTNs) have the potential to connect devices and areas of the world that are under-served by current networks. A critical challenge for DTNs is determining routes through the network without ever having an end-to-end connection, or even knowing which "routers" will be connected at any given time. Prior approaches have focused either on epidemic message replication or on knowledge of the connectivity schedule. The epidemic approach of replicating messages to all nodes is expensive and does not appear to scale well with increasing load. It can, however, operate without any prior network configuration. The alternatives, by requiring a priori connectivity knowledge, appear infeasible for a self-configuring network.In this paper we present a practical routing protocol that only uses observed information about the network. We designed a metric that estimates how long a message will have to wait before it can be transferred to the next hop. The topology is distributed using a link-state routing protocol, where the link-state packets are "flooded" using epidemic routing. The routing is recomputed when connections are established. Messages are exchanged if the topology suggests that a connected node is "closer" than the current node.We demonstrate through simulation that our protocol provides performance similar to that of schemes that have global knowledge of the network topology, yet without requiring that knowledge. Further, it requires a significantly smaller quantity of buffer, suggesting that our approach will scale with the number of messages in the network, where replication approaches may not.
01 Apr 2005
TL;DR: Stable, scalable load-sharing across paths, based on end-to-end measurements, can be achieved on the same rapid time- scale as rate control, namely the time-scale of round-trip times.
Abstract: Dynamic multi-path routing has the potential to improve the reliability and performance of a communication network, but carries a risk. Routing needs to respond quickly to achieve the potential benefits, but not so quickly that the network is destabilized. This paper studies how rapidly routing can respond, without compromising stability.We present a sufficient condition for the local stability of end-to-end algorithms for joint routing and rate control. The network model considered allows an arbitrary interconnection of sources and resources, and heterogeneous propagation delays. The sufficient condition we present is decentralized: the responsiveness of each route is restricted by the round-trip time of that route alone, and not by the round-trip times of other routes. Our results suggest that stable, scalable load-sharing across paths, based on end-to-end measurements, can be achieved on the same rapid time-scale as rate control, namely the time-scale of round-trip times.
22 Aug 2005
TL;DR: This paper explores a new point in this design space that aims to strike a better balance between the extensibility and robustness of a routing infrastructure, and proposes a declarative routing system to express routing protocols using a database query language.
Abstract: The Internet's core routing infrastructure, while arguably robust and efficient, has proven to be difficult to evolve to accommodate the needs of new applications. Prior research on this problem has included new hard-coded routing protocols on the one hand, and fully extensible Active Networks on the other. In this paper, we explore a new point in this design space that aims to strike a better balance between the extensibility and robustness of a routing infrastructure. The basic idea of our solution, which we call declarative routing, is to express routing protocols using a database query language. We show that our query language is a natural fit for routing, and can express a variety of well-known routing protocols in a compact and clean fashion. We discuss the security of our proposal in terms of its computational expressive power and language design. Via simulation, and deployment on PlanetLab, we demonstrate that our system imposes no fundamental limits relative to traditional protocols, is amenable to query optimizations, and can sustain long-lived routes under network churn and congestion.
13 Mar 2005
TL;DR: Two network-layer acknowledgment-based schemes are proposed, termed the TWOACK and the S-TWOACK, which can be simply added-on to any source routing protocol, and found that, in a network where up to 40% of the nodes may be misbehaving, the TWOack scheme results in 20% improvement in packet delivery ratio, with a reasonable additional routing overhead.
Abstract: Mobile ad hoc networks (MANETs) operate on the basic underlying assumption that all participating nodes fully collaborate in self-organizing functions. However, performing network functions consumes energy and other resources. Therefore, some network nodes may decide against cooperating with others. Providing these selfish nodes, also termed misbehaving nodes, with an incentive to cooperate has been an active research area recently. In this paper, we propose two network-layer acknowledgment-based schemes, termed the TWOACK and the S-TWOACK schemes, which can be simply added-on to any source routing protocol. The TWOACK scheme detects such misbehaving nodes, and then seeks to alleviate the problem by notifying the routing protocol to avoid them in future routes. Details of the two schemes and our evaluation results based on simulations are presented in this paper. We have found that, in a network where up to 40% of the nodes may be misbehaving, the TWOACK scheme results in 20% improvement in packet delivery ratio, with a reasonable additional routing overhead.
TL;DR: This paper presents a new reliable transport layer protocol for ad hoc networks called ATP (ad hoc transport protocol), and shows through ns2-based simulations that ATP outperforms default TCP as well as TCP-ELFN and ATCP.
Abstract: Existing works have approached the problem of reliable transport in ad hoc networks by proposing mechanisms to improve TCP's performance over such networks, In this paper, we show through detailed arguments and simulations that several of the design elements in TCP are fundamentally inappropriate for the unique characteristics of ad hoc networks. Given that ad hoc networks are typically stand-alone, we approach the problem of reliable transport from the perspective that it is justifiable to develop an entirely new transport protocol that is not a variant of TCP. Toward this end, we present a new reliable transport layer protocol for ad hoc networks called ATP (ad hoc transport protocol). We show through ns2-based simulations that ATP outperforms default TCP as well as TCP-ELFN and ATCP.
01 Jan 2005
TL;DR: This chapter reviews some of the best metaheuristics proposed in recent years for the Vehicle Routing Problem based on local search, on population search and on learning mechanisms.
Abstract: This chapter reviews some of the best metaheuristics proposed in recent years for the Vehicle Routing Problem. These are based on local search, on population search and on learning mechanisms. Comparative computational results are provided on a set of 34 benchmark instances.
TL;DR: In larger networks that are not uniformly populated with nodes, terminode routing outperforms, existing location-based or MANET routing protocols, and in smaller networks; the performance is comparable to MANet routing protocols.
Abstract: Using location information to help routing is often proposed as a means to achieve scalability in large mobile ad hoc networks. However, location-based routing is difficult when there are holes in the network topology and nodes are mobile or frequently disconnected to save battery. Terminode routing, presented here, addresses these issues. It uses a combination of location-based routing (terminode remote routing, TRR), used when the destination is far, and link state-routing (terminode local routing, TLR), used when the destination is close. TRR uses anchored paths, a list of geographic points (not nodes) used as loose source routing information. Anchored paths are discovered and managed by sources, using one of two low overhead protocols: friend assisted path discovery and geographical map-based path discovery. Our simulation results show that terminode routing performs well in networks of various sizes. In smaller networks; the performance is comparable to MANET routing protocols. In larger networks that are not uniformly populated with nodes, terminode routing outperforms, existing location-based or MANET routing protocols.
13 Mar 2005
TL;DR: This study demonstrates that when practical MANET sizes are considered, robustness to mobility and the constant factors matter more than the asymptotic costs of location service protocols.
Abstract: Geographic routing protocols allow stateless routing in mobile ad hoc networks (MANETs) by taking advantage of the location information of mobile nodes and thus are highly scalable. A central challenge in geographic routing protocols is the design of scalable distributed location services that track mobile node locations. A number of location services have been proposed, but little is known about the relative performance of these location services. In this paper, we perform a detailed performance comparison of three rendezvous-based location services that cover a range of design choices: a quorum-based protocol (XYLS) which disseminates each node's location to O(/spl radic/N) nodes, a hierarchical protocol (GLS) which disseminates each node's location to O(logN) nodes, and a geographic hashing based protocol (GHLS) which disseminates each node's location to O(1) nodes. We present a quantitative model of protocol overheads for predicting the performance tradeoffs of the protocols for static networks. We then analyze the performance impact of mobility on these location services. Finally, we compare the performance of routing protocols equipped with the three location services with two topology-based routing protocols, AODV and DSR, for a wide range of network sizes. Our study demonstrates that when practical MANET sizes are considered, robustness to mobility and the constant factors matter more than the asymptotic costs of location service protocols. In particular, while GLS scales better asymptotically, GHLS is far simpler, transmits fewer control packets, and delivers more data packets than GLS when used with geographic routing in MANETs of sizes considered practical today and in the near future. Similarly, although XYLS scales worse asymptotically than GLS, it transmits fewer control packets and delivers more data packets than GLS in large mobile networks.
13 Sep 2005
TL;DR: The bounds of information propagation under various traffic patterns are characterized and a new technique and algorithm that can achieve these limits are described.
Abstract: A goal in Vehicular Ad hoc Networks (VANETs) is to enable the dissemination of traffic and road conditions such as local congestion and surface ice as detected by independently moving vehicles. This activity known as Information Warning Functions is useful for vehicles on the highway and enables early reaction. This problem can be described as the direc- tional propagation of information originating from linearly- distributed mobile nodes on a rectilinear plane. By using limited-range packet radios and attribute-based routing, we are able to isolate vehicular from network traffic and permit directional propagation of messages outward from the point of origin. For example, it is desirable to propagate the occurrence of congestion created by an accident in both the forward and backward directions on a highway. We assume the use of multi-hop routing in clusters of connected vehicles to achieve a propagation rate that exceeds the speeds of individual carrier vehicles. We characterize the bounds of information propagation under various traffic patterns and describe a new technique and algorithm that can achieve these limits. We also show an implementation of the dissemination algorithm as a routing protocol using a combination of MANET (mobile ad hoc networking) and DTN (delay tolerant networking) methodologies.
28 Aug 2005
TL;DR: Corsac is presented, a cooperation-optimal protocol consisting of a routing protocol and a forwarding protocol that addresses the challenge in wireless ad-hoc networks that a link's cost is determined by two nodes together.
Abstract: In many applications, wireless ad-hoc networks are formed by devices belonging to independent users. Therefore, a challenging problem is how to provide incentives to stimulate cooperation. In this paper, we study ad-hoc games---the routing and packet forwarding games in wireless ad-hoc networks. Unlike previous work which focuses either on routing or on forwarding, this paper investigates both routing and forwarding. We first uncover an impossibility result---there does not exist a protocol such that following the protocol to always forward others' traffic is a dominant action. Then we define a novel solution concept called cooperation-optimal protocols. We present Corsac, a cooperation-optimal protocol consisting of a routing protocol and a forwarding protocol. The routing protocol of Corsac integrates VCG with a novel cryptographic technique to address the challenge in wireless ad-hoc networks that a link's cost (ie, its type) is determined by two nodes together. Corsac also applies efficient cryptographic techniques to design a forwarding protocol to enforce the routing decision, such that fulfilling the routing decision is the optimal action of each node in the sense that it brings the maximum utility to the node. Additionally, we extend our framework to a practical radio propagation model where a transmission is successful with a probability. We evaluate our protocols using simulations. Our evaluations demonstrate that our protocols provide incentives for nodes to forward packets.
22 Aug 2005
TL;DR: New semantic models for DTN multicast are proposed and several multicast routing algorithms with different routing strategies are developed, and a framework to evaluate these algorithms in DTNs is presented.
Abstract: Delay tolerant networks (DTNs) are a class of emerging networks that experience frequent and long-duration partitions. These networks have a variety of applications in situations such as crisis environments and deep-space communication. In this paper, we study the problem of multicasting in DTNs. Multicast supports the distribution of data to a group of users, a service needed for many potential DTN applications. While multicasting in the Internet and mobile ad hoc networks has been studied extensively, due to the unique characteristic of frequent partitioning in DTNs, multicasting in DTNs is a considerably different and challenging problem. It not only requires new definitions of multicast semantics but also brings new issues to the design of routing algorithms. In this paper, we propose new semantic models for DTN multicast and develop several multicast routing algorithms with different routing strategies. We present a framework to evaluate these algorithms in DTNs. To the best of our knowledge, this is the first study of multicasting in DTNs. Our objectives are to understand how routing performance is affected by the availability of knowledge about network topology and group membership and to guide the design of DTN routing protocols. Using ns simulations, we find that efficient multicast routing for DTNs can be constructed using only partial knowledge. In addition, accurate topology information is generally more important in routing than up-to-date membership information. We also find that routing algorithms that forward data along multiple paths achieve better delivery ratios, especially when available knowledge is limited.
TL;DR: It is shown by simulation that the RDG outperforms previously proposed routing graphs in the context of the Greedy perimeter stateless routing (GPSR) protocol, and theoretical bounds on the quality of paths discovered using GPSR are investigated.
Abstract: We propose a new routing graph, the restricted Delaunay graph (RDG), for mobile ad hoc networks. Combined with a node clustering algorithm, the RDG can be used as an underlying graph for geographic routing protocols. This graph has the following attractive properties: 1) it is planar; 2) between any two graph nodes there exists a path whose length, whether measured in terms of topological or Euclidean distance, is only a constant times the minimum length possible; and 3) the graph can be maintained efficiently in a distributed manner when the nodes move around. Furthermore, each node only needs constant time to make routing decisions. We show by simulation that the RDG outperforms previously proposed routing graphs in the context of the Greedy perimeter stateless routing (GPSR) protocol. Finally, we investigate theoretical bounds on the quality of paths discovered using GPSR.
TL;DR: 18 reasons why short-hop routing is not as beneficial as it seems to be are listed and experimental evidence is provided to support this claim.
Abstract: For multihop wireless networks, a fundamental question is whether it is advantageous to route over many short hops (short-hop routing) or over a smaller number of longer hops (long-hop routing). Short-hop routing has gained a lot of support, and its proponents mainly produce two arguments: reduced energy consumption and higher signal-to-interference ratios. Both arguments stem from a simplified analysis based on crude channel models that neglects delay, end-to-end reliability, bias power consumption, the impact of channel coding, mobility, and routing overhead. In this article we shed more light on these issues by listing 18 reasons why short-hop routing is not as beneficial as it seems to be. We also provide experimental evidence to support this claim. The conclusion is that for many networks, long-hop routing is in every aspect a very competitive strategy.
08 Mar 2005
TL;DR: A proof-of-concept implementation of a secure routing protocol based on AODV over IPv6, further reinforced by a routing protocol independent intrusion detection system (IDS) for ad hoc networks.
Abstract: Numerous schemes have been proposed for secure routing and intrusion detection for ad hoc networks. Yet, little work exists in actually implementing such schemes on small handheld devices. In this paper, we present a proof-of-concept implementation of a secure routing protocol based on AODV over IPv6, further reinforced by a routing protocol independent intrusion detection system (IDS) for ad hoc networks. Security features in the routing protocol include mechanisms for nonrepudiation and authentication, without relying on the availability of a certificate authority (CA) or a key distribution center (KDC). We present the design and implementation details of our system, the practical considerations involved, and how these mechanisms can be used to detect and thwart malicious attacks. We discuss several scenarios where the secure routing and intrusion detection mechanisms isolate and deny network resources to nodes deemed malicious. We also discuss shortcomings in our approach, and conclude with lessons learned and ideas for future work
01 Jan 2005
TL;DR: Simulation studies using the proposed extensible on-demand power management framework with the Dynamic Source Routing protocol show a reduction in energy consumption near 50% when compared to a network without power management under both long-lived CBR traffic and on–off traffic loads, with comparable throughput and latency.
Abstract: Battery power is an important resource in ad hoc networks. It has been observed that in ad hoc networks, energy consumption does not reflect the communication activities in the network. Many existing energy conservation protocols based on electing a routing backbone for global connectivity are oblivious to traffic characteristics. In this paper, we propose an extensible on-demand power management framework for ad hoc networks that adapts to traffic load. Nodes maintain soft-state timers that determine power management transitions. By monitoring routing control messages and data transmission, these timers are set and refreshed on-demand. Nodes that are not involved in data delivery may go to sleep as supported by the MAC protocol. This soft state is aggregated across multiple flows and its maintenance requires no additional out-of-band messages. We implement a prototype of our framework in the ns-2 simulator that uses the IEEE 802.11 MAC protocol. Simulation studies using our scheme with the Dynamic Source Routing protocol show a reduction in energy consumption near 50% when compared to a network without power management under both long-lived CBR traffic and on–off traffic loads, with comparable throughput and latency. Preliminary results also show that it outperforms existing routing backbone election approaches.