Showing papers on "Multipath routing published in 2003"

Secure routing in wireless sensor networks: attacks and countermeasures

Abstract: We consider routing security in wireless sensor networks. Many sensor network routing protocols have been proposed, but none of them have been designed with security as a goal. We propose security goals for routing in sensor networks, show how attacks against ad-hoc and peer-to-peer networks can be adapted into powerful attacks against sensor networks, introduce two classes of novel attacks against sensor networks sinkholes and HELLO floods, and analyze the security of all the major sensor network routing protocols. We describe crippling attacks against all of them and suggest countermeasures and design considerations. This is the first such analysis of secure routing in sensor networks.

The benefits of coding over routing in a randomized setting

Abstract: A novel randomized network coding approach for robust, distributed transmission and compression of information in networks is presented, and its advantages over routing-based approaches is demonstrated.

SEAD: Secure efficient distance vector routing for mobile wireless ad hoc networks

Abstract: An ad hoc network is a collection of wireless computers (nodes), communicating among themselves over possibly multihop paths, without the help of any infrastructure such as base stations or access points. Although many previous ad hoc network routing protocols have been based in part on distance vector approaches, they have generally assumed a trusted environment. In this paper, we design and evaluate the Secure Efficient Ad hoc Distance vector routing protocol (SEAD), a secure ad hoc network routing protocol based on the design of the Destination-Sequenced Distance-Vector routing protocol. In order to support use with nodes of limited CPU processing capability, and to guard against Denial-of-Service attacks in which an attacker attempts to cause other nodes to consume excess network bandwidth or processing time, we use efficient one-way hash functions and do not use asymmetric cryptographic operations in the protocol. SEAD performs well over the range of scenarios we tested, and is robust against multiple uncoordinated attackers creating incorrect routing state in any other node, even in spite of any active attackers or compromised nodes in the network.

Geometric ad-hoc routing: of theory and practice

Abstract: All too often a seemingly insurmountable divide between theory and practice can be witnessed. In this paper we try to contribute to narrowing this gap in the field of ad-hoc routing. In particular we consider two aspects: We propose a new geometric routing algorithm which is outstandingly efficient on practical average-case networks, however is also in theory asymptotically worst-case optimal. On the other hand we are able to drop the formerly necessary assumption that the distance between network nodes may not fall below a constant value, an assumption that cannot be maintained for practical networks. Abandoning this assumption we identify from a theoretical point of view two fundamentamentally different classes of cost metrics for routing in ad-hoc networks.

Worst-Case optimal and average-case efficient geometric ad-hoc routing

Abstract: In this paper we present GOAFR, a new geometric ad-hoc routing algorithm combining greedy and face routing. We evaluate this algorithm by both rigorous analysis and comprehensive simulation. GOAFR is the first ad-hoc algorithm to be both asymptotically optimal and average-case efficient. For our simulations we identify a network density range critical for any routing algorithm. We study a dozen of routing algorithms and show that GOAFR outperforms other prominent algorithms, such as GPSR or AFR.

Multipath Routing in Mobile Ad Hoc Networks: Issues and Challenges

Abstract: Mobile ad hoc networks (MANETs) consist of a collection of wireless mobile nodes which dynamically exchange data among themselves without the reliance on a fixed base station or a wired backbone network MANET nodes are typically distinguished by their limited power, processing, and memory resources as well as high degree of mobility In such networks, the wireless mobile nodes may dynamically enter the network as well as leave the network Due to the limited transmission range of wireless network nodes, multiple hops are usually needed for a node to exchange information with any other node in the network Thus routing is a crucial issue to the design of a MANET In this paper, we specifically examine the issues of multipath routing in MANETs Multipath routing allows the establishment of multiple paths between a single source and single destination node It is typically proposed in order to increase the reliability of data transmission (ie, fault tolerance) or to provide load balancing Load balancing is of especial importance in MANETs because of the limited bandwidth between the nodes We also discuss the application of multipath routing to support application constraints such as reliability, load-balancing, energy-conservation, and Quality-of-Service (QoS)

Performance of multihop wireless networks: shortest path is not enough

Abstract: Existing wireless ad hoc routing protocols typically find routes with the minimum hop-count. This paper presents experimental evidence from two wireless test-beds which shows that there are usually multiple minimum hop-count paths, many of which have poor throughput. As a result, minimum-hop-count routing often chooses routes that have significantly less capacity than the best paths that exist in the network. Much of the reason for this is that many of the radio links between nodes have loss rates low enough that the routing protocol is willing to use them, but high enough that much of the capacity is consumed by retransmissions. These observations suggest that more attention be paid to link quality when choosing ad hoc routes; the paper presents measured link characteristics likely to be useful in devising a better path quality metric.

Trajectory based forwarding and its applications

Abstract: Trajectory based forwarding (TBF) is a novel methodto forward packets in a dense ad hoc network that makes it possible to route a packet along a predefined curve. It is a hybrid between source based routing and Cartesian forwarding in that the trajectory is set by the source, but the forwarding decision is based on the relationship to the trajectory rather than names of intermediate nodes. The fundamental aspects of TBF are: it decouples path naming from the actual path; it provides cheap path diversity; it trades off communication for computation. These aspects address the double scalability issue with respect to mobility rate and network size. In addition, TBF provides a common framework for many services such as: broadcasting, discovery, unicast, multicast and multipath routing in ad hoc networks. TBF requires that nodes know their position relative to a coordinate system. While a global coordinate system afforded by a system such as GPS would be ideal, approximate positioning methods provided by other algorithms are also usable.

Characterizing achievable rates in multi-hop wireless networks: the joint routing and scheduling problem

Abstract: This paper considers the problem of determining the achievable rates in multi-hop wireless networks. We consider the problem of jointly routing the flows and scheduling transmissions to achieve a given rate vector. We develop tight necessary and sufficient conditions for the achievability of the rate vector. We develop efficient and easy to implement Fully Polynomial Time Approximation Schemes for solving the routing problem. The scheduling problem is a solved as a graph edge-coloring problem. We show that this approach guarantees that the solution obtained is within 67% of the optimal solution in the worst case and, in practice, is typically within about 80% of the optimal solution. The approach that we use is quite flexible and is a promising method to handle more sophisticated interference conditions, multiple channels, multiple antennas, and routing with diversity requirements.

Making intra-domain routing robust to changing and uncertain traffic demands: understanding fundamental tradeoffs

Abstract: Intra-domain traffic engineering can significantly enhance the performance of large IP backbone networks. Two important components of traffic engineering are understanding the traffic demandsand configuring the routing protocols. These two components are inter-linked, as it is widely believed that an accurate view of traffic is important for optimizing the configuration of routing protocols and through that, the utilization of the network.This basic premise, however, never seems to have been quantified --How important is accurate knowledge of traffic demands for obtaining good utilization of the network? Since traffic demand values are dynamic and illusive, is it possible to obtain a routing that is "robust" to variations in demands? Armed with enhanced recent algorithmic tools we explore these questions on a diverse collection of ISP networks. We arrive at a surprising conclusion: it is possible to obtain a robust routing that guarantees a nearly optimal utilization with a fairly limited knowledge of the applicable traffic demands.

Performance analysis of reactive shortest path and multipath routing mechanism with load balance

Abstract: Research on multipath routing protocols to provide improved throughput and route resilience as compared with single-path routing has been explored in details in the context of wired networks. However, multipath routing mechanism has not been explored thoroughly in the domain of ad hoc networks. In this paper, we analyze and compare reactive single-path and multipath routing with load balance mechanisms in ad hoc networks, in terms of overhead, traffic distribution and connection throughput. The results reveals that in comparison with general single-path routing protocol, multipath routing mechanism creates more overheads but provides better performance in congestion and capacity provided that the route length is within a certain upper bound which is derivable. The analytical results are further confirmed by simulation.

On selfish routing in internet-like environments

Abstract: A recent trend in routing research is to avoid inefficiencies in network-level routing by allowing hosts to either choose routes themselves (e.g., source routing) or use overlay routing networks (e.g., Detour or RON). Such approaches result in selfish routing, because routing decisions are no longer based on system-wide criteria but are instead designed to optimize host-based or overlay-based metrics. A series of theoretical results showing that selfish routing can result in suboptimal system behavior have cast doubts on this approach. In this paper, we use a game-theoretic approach to investigate the performance of selfish routing in Internet-like environments. We focus on intra-domain network environments and use realistic topologies and traffic demands in our simulations. We show that in contrast to theoretical worst cases, selfish routing achieves close to optimal average latency in such environments. However, such performance benefit comes at the expense of significantly increased congestion on certain links. Moreover, the adaptive nature of selfish overlays can significantly reduce the effectiveness of traffic engineering by making network traffic less predictable.

Minimum energy disjoint path routing in wireless ad-hoc networks

Abstract: We develop algorithms for finding minimum energy disjoint paths in an all-wireless network, for both the node and link-disjoint cases. Our major results include a novel polynomial time algorithm that optimally solves the minimum energy 2 link-disjoint paths problem, as well as a polynomial time algorithm for the minimum energy k node-disjoint paths problem. In addition, we present efficient heuristic algorithms for both problems. Our results show that link-disjoint paths consume substantially less energy than node-disjoint paths. We also found that the incremental energy of additional link-disjoint paths is decreasing. This finding is somewhat surprising due to the fact that in general networks additional paths are typically longer than the shortest path. However, in a wireless network, additional paths can be obtained at lower energy due to the broadcast nature of the wireless medium. Finally, we discuss issues regarding distributed implementation and present distributed versions of the optimal centralized algorithms presented in the paper.

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. The recent literature has examined a variety of schemes that achieve greater data aggregation by routing data with regard to the underlying spatial correlation. A well known conclusion from these papers is that the nature of optimal routing with compression depends on the correlation level. In this article we show the existence of a simple, practical, and static correlation-unaware clustering scheme that satisfies a min-max near-optimality condition. The implication for system design is that a static correlation-unaware scheme can perform as well as sophisticated adaptive schemes for joint routing and compression.

A multiobjective evolutionary algorithm for solving vehicle routing problem with time windows

Abstract: Vehicle routing problem with time windows (VRPTW) involves the routing of a set of vehicles with limited capacity from a central depot to a set of geographically dispersed customers with known demands and predefined time windows. This paper proposes a hybrid multiobjective evolutionary algorithm (HMOEA) that incorporates various heuristics for local exploitation in the evolutionary search and the concept of Pareto's optimality for solving multiobjective optimization in VRPTW problems. The proposed HMOEA optimizes all routing constraints and objectives simultaneously, which improves the routing solutions in many aspects, such as lower routing cost, wider scattering area and better convergence trace.

Pricing network edges for heterogeneous selfish users

Abstract: We study the negative consequences of selfish behavior in a congested network and economic means of influencing such behavior. We consider a model of selfish routing in which the latency experienced by network traffic on an edge of the network is a function of the edge congestion, and network users are assumed to selfishly route traffic on minimum-latency paths. The quality of a routing of traffic is measured by the sum of travel times (the total latency).It is well known that the outcome of selfish routing (a Nash equilibrium) does not minimize the total latency. An ancient strategy for improving the selfish solution is the principle of marginal cost pricing, which asserts that on each edge of the network, each network user on the edge should pay a tax offsetting the congestion effects caused by its presence. By pricing network edges according to this principle, the inefficiency of selfish routing can always be eradicated.This result, while fundamental, assumes a very strong homogeneity property: all network users are assumed to trade off time and money in an identical way. The guarantee also ignores both the algorithmic aspects of edge pricing and the unfortunate possibility that an efficient routing of traffic might only be achieved with exorbitant taxes. Motivated by these shortcomings, we extend this classical work on edge pricing in several different directions and prove the following results.We prove that the edges of a single-commodity network can always be priced so that an optimal routing of traffic arises as a Nash equilibrium, even for very general heterogeneous populations of network users.When there are only finitely many different types of network users and all edge latency functions are convex, we show how to compute such edge prices efficiently.We prove that an easy-to-check mathematical condition on the population of heterogeneous network users is both necessary and sufficient for the existence of edge prices that induce an optimal routing while requiring only moderate taxes.

Secure message transmission in mobile ad hoc networks

Abstract: The vision of nomadic computing with its ubiquitous access has stimulated much interest in the mobile ad hoc networking (MANET) technology. However, its proliferation strongly depends on the availability of security provisions, among other factors. In the open, collaborative MANET environment, practically any node can maliciously or selfishly disrupt and deny communication of other nodes. In this paper, we propose the secure message transmission (SMT) protocol to safeguard the data transmission against arbitrary malicious behavior of network nodes. SMT is a lightweight, yet very effective, protocol that can operate solely in an end-to-end manner. It exploits the redundancy of multi-path routing and adapts its operation to remain efficient and effective even in highly adverse environments. SMT is capable of delivering up to 83% more data messages than a protocol that does not secure the data transmission. Moreover, SMT achieves up to 65% lower end-to-end delays and up to 80% lower delay variability, compared with an alternative single-path protocol––a secure data forwarding protocol, which we term secure single path (SSP) protocol. Thus, SMT is better suited to support quality of service for real-time communications in the ad hoc networking environment. The security of data transmission is achieved without restrictive assumptions on the network nodes trust and network membership, without the use of intrusion detection schemes, and at the expense of moderate multi-path transmission overhead only. � 2003 Elsevier B.V. All rights reserved.

A fault-tolerant and deadlock-free routing protocol in 2D meshes based on odd-even turn model

Abstract: We propose a deterministic fault-tolerant and deadlock-free routing protocol in two-dimensional (2D) meshes based on dimension-order routing and the odd-even turn model. The proposed protocol, called extended X-Y routing, does not use any virtual channels by prohibiting certain locations of faults and destinations. Faults are contained in a set of disjointed rectangular regions called faulty blocks. The number of faults to be tolerated is unbounded as long as nodes outside faulty blocks are connected in the 2D mesh network. The extended X-Y routing can also be used under a special convex fault region called an orthogonal faulty block, which can be derived from a given faulty block by activating some nonfaulty nodes in the block. Extensions to partially adaptive routing, traffic and adaptivity-balancing using virtual networks, and routing without constraints using virtual channels and virtual networks are also discussed.

Quality of service routing in ad-hoc networks using OLSR

Abstract: In an ad-hoc network, all communication is done over wireless media, without the help of wired base stations. While many routing protocols have been developed to find and maintain routes based on a best-effort service model, quality-of-service (QoS) routing in an ad-hoc network is difficult because the network topology may change constantly and the available state information for routing is inherently imprecise. In this paper, we discuss how to support QoS routing in OLSR (optimized link state routing protocol, one of the routing protocols under study by the IETF MANET Working Group). We develop heuristics that allow OLSR to find the maximum bandwidth path, show through simulation that these heuristics do improve OLSR in the static network case, and finally, we prove that for our ad-hoc network model, two of the heuristics are indeed optimal (i.e., guarantee that the highest-bandwidth path between any two nodes is found).

Trade-off between traffic overhead and reliability in multipath routing for wireless sensor networks

Abstract: In wireless sensor networks (WSN) data produced by one or more sources usually has to be routed through several intermediate nodes to reach the destination. Problems arise when intermediate nodes to reach the destination. Problems arise when intermediate nodes fail to forward the incoming messages. The reliability of the system can be increased by providing several paths from source to destination and sending the same packet through each of them (the algorithm is known as multipath routing). Using this technique, the traffic increases significantly. In this paper, we analyze a new mechanism that enables the trade-off between the amount of traffic and the reliability. The data packet is split in k subpackets (k = number of disjoined paths from source to destination). If only E/sub k/ subpackets (E/sub k/ < k) are necessary to rebuild the original data packet (condition obtained by adding redundancy to each subpacket), then the trade-off between traffic and reliability can be controlled.

Diverse routing in optical mesh networks

Abstract: We study the diverse routing problem in optical mesh networks. We use a general framework based on shared risk link groups to model the problem. We prove that the diverse routing problem is indeed NP-complete, a result that has been conjectured by several researchers previously. In fact, we show that even the fiber-span-disjoint paths problem, a special case of the diverse routing problem, is also NP-complete. We then develop an integer linear programming formulation and show through numerical results that it is a very viable method to solve the diverse routing problem for most optical networks found in many applications which typically have no more than a few hundred nodes and fiber spans.

Best-path vs. multi-path overlay routing

Abstract: Time-varying congestion on Internet paths and failures due to software, hardware, and configuration errors often disrupt packet delivery on the Internet.Many aproaches to avoiding these problems use multiple paths between two network locations. These approaches rely on a path-independence assumption in order to work well; i.e., they work best when the problems on different paths between two locations are uncorrelated in time.This paper examines the extent to which this assumption holds on the Internet by analyzing 14 days of data collected from 30 nodes in the RON testbed. We examine two problems that manifest themselves---congestion-triggered loss and path failures---and find that the chances of losing two packets between the same hosts is nearly as high when those packets are sent through an intermediate node (60%) as when they are sent back-to-back on the same path (70%). In so doing, we also compare two different ways of taking advantage of path redundancy proposed in the literature: mesh routing based on packet replication, and reactive routing based on adaptive path selection.

Cooperative packet caching and shortest multipath routing in mobile ad hoc networks

Abstract: A mobile ad hoc network is an autonomous system of infrastructureless, multihop wireless mobile nodes. Reactive routing protocols perform well in such an environment due to their ability to cope quickly against topological changes. In this paper, we propose a new routing protocol called Caching and Multipath (CHAMP) Routing Protocol. CHAMP uses cooperative packet caching and shortest multipath routing to reduce packet loss due to frequent route breakdowns. Simulation results reveal that by using a five-packet data cache, CHAMP exhibits excellent improvement in packet delivery, outperforming AODV and DSR by at most 30% in stressful scenarios. Furthermore, end-to-end delay is significantly reduced while routing overhead is lower at high mobility rates.

GOAL: a load-balanced adaptive routing algorithm for torus networks

Abstract: We introduce a load-balanced adaptive routing algorithm for torus networks, GOAL - Globally Oblivious Adaptive Locally - that provides high throughput on adversarial traffic patterns, matching or exceeding fully randomized routing and exceeding the worst-case performance of Chaos [2], RLB [14], and minimal routing [8] by more than 40%. GOAL also preserves locality to provide up to 4.6× the throughput of fully randomized routing [19] on local traffic. GOAL achieves global load balance by randomly choosing the direction to route in each dimension. Local load balance is then achieved by routing in the selected directions adaptively. We compare the throughput, latency, stability and hot-spot performance of GOAL to six previously published routing algorithms on six specific traffic patterns and 1,000 randomly generated permutations.

Efficient Security Mechanisms for Routing Protocolsa.

Abstract: As our economy and critical infrastructure increasingly rely on the Internet, securing routing protocols becomes of critical importance. In this paper, we present four new mechanisms as tools for securing distance vector and path vector routing protocols. For securing distance vector protocols, our hash tree chain mechanism forces a router to increase the distance (metric) when forwarding a routing table entry. To provide authentication of a received routing update in bounded time, we present a new mechanism, similar to hash chains, that we call tree-authenticated oneway chains. For cases in which the maximum metric is large, we present skiplists, which provides more efficient initial computation cost and more efficient element verification; this mechanism is based on a new cryptographic mechanism, called MW-chains, which we also present. For securing path vector protocols, our cumulative authentication mechanism authenticates the list of routers on the path in a routing update, preventing removal or reordering of the router addresses in the list; the mechanism uses only a single authenticator in the routing update rather than one per router address. We also present a simple mechanism to securely switch one-way chains, by authenticating the next one-way chain using the previous one. These mechanisms are all based on efficient symmetric cryptographic techniques and can be used as building blocks for securing routing protocols.

System and method for providing redundant routing capabilities for a network node

Abstract: A routing device that provides redundancy for a node is envisioned. The routing device has a dynamic routing module operable to start functioning at a particular time. A configuration manager is provided. The configuration manager is coupled to a second routing device and stores configuration information associated with operational characteristics of a dynamic routing module associated with the second routing device. A network information module stores routing information from the second routing device. The dynamic routing module is executed upon an indication that the second dynamic routing device is no longer operating, and the configuration device configures the dynamic routing module according to the stored configuration information.

Secure traceroute to detect faulty or malicious routing

Abstract: Network routing is vulnerable to disruptions caused by malfunctioning or malicious routers that draw traffic towards themselves but fail to correctly forward the traffic. The existing approach to addressing this problem is to secure the routing protocol by having it validate routing updates, i.e., verify their authenticity, accuracy, and/or consistency. In this paper, we argue that it is also important to ensure the robustness of packet forwarding itself. To this end, we propose a different approach, the central idea of which is a secure traceroute protocol that enables end hosts or routers to detect and locate the source of (arbitrarily severe) routing misbehaviors, so that appropriate action can be taken.

Dynamic routing of restorable bandwidth-guaranteed tunnels using aggregated network resource usage information

Abstract: This paper presents new algorithms for dynamic routing of restorable bandwidth-guaranteed paths. We assume that connection requests one-by-one and have to be routed with no a priori knowledge of future arrivals. In order to guarantee restorability, in addition to determining an active path to route each request, an alternate link (node) disjoint backup (restoration) path has to be determined for the request at the time of connection initiation. This joint on-line routing problem is becoming particularly important in optical networks and in multiprotocol label switching (MPLS)-based networks due to the trend in backbone networks toward dynamic provisioning of bandwidth-guaranteed or wavelength paths. A straightforward solution for the restoration problem is to find two disjoint paths. However, this results in excessive resource usage. Given a restoration objective, such as protection against single-link failures, backup path bandwidth usage can be reduced by judicious sharing of backup paths amongst certain active paths while still maintaining restorability. The best sharing performance is achieved if the routing of every path in progress in the network is known to the routing algorithm at the time of a new path setup. We give an integer programming formulation for this problem which is new. Complete path routing knowledge is a reasonable assumption for a centralized routing algorithm. However, it is not often desirable, particularly when distributed routing is preferred. We show that an aggregate information scenario which uses only aggregated and not per-path information provides sufficient information for a suitably developed algorithm to be able to perform almost as well as the complete information scenario. Disseminating this aggregate information is feasible using proposed traffic engineering extensions to routing protocols. We formulate the dynamic restorable bandwidth routing problem in this aggregate information scenario and develop efficient routing algorithms. We show that the performance of our aggregate information-based algorithm is close to the complete information bound.

An approach to alleviate link overload as observed on an IP backbone

Abstract: Shortest path routing protocols may suffer from congestion due to the use of a single shortest path between a source and a destination. The goal of our work is to first understand how links become overloaded in an IP backbone, and then to explore if the routing protocol, -either in its existing form, or in some enhanced form could be made to respond immediately to overload and reduce the likelihood of its occurrence. Our method is to use extensive measurements of Sprint's backbone network, measuring 138 links between September 2000 and June 2001. We find that since the backbone is designed to be overprovisioned, link overload is rare, and when it occurs, 80% of the time it is caused due to link failures. Furthermore, we find that when a link is overloaded, few (if any) other links in the network are also overloaded. This suggests that deflecting packets to less utilized alternate paths could be an effective method for tackling overload. We analytically derive the condition that a network, which has multiple equal length shortest paths between every pair of nodes (as is common in the highly meshed backbone networks) can provide for loop-free deflection paths if all the link weights are within a ratio 1 + 1/(d- I) of each other; where d is the diameter of the network. Based on our measurements, the nature of the backbone topology and the careful use of link weights, we propose a deflection routing algorithm to tackle link overload where each node makes local decisions. Simulations suggest that this can be a simple and efficient way to overcome link overload, without requiring any changes to the routing protocol.

Routing using potentials: a dynamic traffic-aware routing algorithm

Abstract: We present a routing paradigm called PBR that utilizes steepest gradient search methods to route data packets. More specifically, the PBR paradigm assigns scalar potentials to network elements and forwards packets in the direction of maximum positive force. We show that the family of PBR schemes are loop free and that the standard shortest path routing algorithms are a special case of the PBR paradigm. We then show how to design a potential function that accounts for traffic conditions at a node. The resulting routing algorithm routes around congested areas while preserving the key desirable properties of IP routing mechanisms including hop-by-hop routing, local route computations and statistical multiplexing. Our simulations using the ns simulator indicate that the traffic aware routing algorithm shows significant improvements in end-to-end delay and jitter when compared to standard shortest path routing algorithms. The simulations also indicate that our algorithm does not incur too much control overheads and is fairly stable even when traffic conditions are dynamic.