Showing papers on "Link-state routing protocol published in 2006"

MaxProp: Routing for Vehicle-Based Disruption-Tolerant Networks

Abstract: Disruption-tolerant networks (DTNs) attempt to route network messages via intermittently connected nodes. Routing in such environments is difficult because peers have little information about the state of the partitioned network and transfer opportunities between peers are of limited duration. In this paper, we propose MaxProp, a protocol for effective routing of DTN messages. MaxProp is based on prioritizing both the schedule of packets transmitted to other peers and the schedule of packets to be dropped. These priorities are based on the path likelihoods to peers according to historical data and also on several complementary mechanisms, including acknowledgments, a head-start for new packets, and lists of previous intermediaries. Our evaluations show that MaxProp performs better than protocols that have access to an oracle that knows the schedule of meetings between peers. Our evaluations are based on 60 days of traces from a real DTN network we have deployed on 30 buses. Our network, called UMassDieselNet, serves a large geographic area between five colleges. We also evaluate MaxProp on simulated topologies and show it performs well in a wide variety of DTN environments.

Ad hoc on-demand multipath distance vector routing

Abstract: We develop an on-demand, multipath distance vector routing protocol for mobile ad hoc networks. Specifically, we propose multipath extensions to a well-studied single path routing protocol known as ad hoc on-demand distance vector (AODV). The resulting protocol is referred to as ad hoc on-demand multipath distance vector (AOMDV). The protocol guarantees loop freedom and disjointness of alternate paths. Performance comparison of AOMDV with AODV using ns-2 simulations shows that AOMDV is able to effectively cope with mobility-induced route failures. In particular, it reduces the packet loss by up to 40% and achieves a remarkable improvement in the end-to-end delay (often more than a factor of two). AOMDV also reduces routing overhead by about 30% by reducing the frequency of route discovery operations. Copyright © 2006 John Wiley & Sons, Ltd.

Interference aware routing in multi-radio wireless mesh networks

Abstract: We address the problem of interference aware routing in multi-radio infrastructure mesh networks wherein each mesh node is equipped with multiple radio interfaces and a subset of nodes serve as Internet gateways. We present a new interference aware routing metric - iAWARE that aids in finding paths that are better in terms of reduced interflow and intra-flow interference. We incorporate this metric and new support for multi-radio networks in the well known AODV routing protocol to design an enhanced AODV-MR routing protocol. We study the performance of our new routing metric by implementing it in our wireless testbed consisting of 12 mesh nodes. We show that iAWARE tracks changes in interfering traffic far better than existing well known link metrics such as ETT and IRU. We also demonstrate that our AODV-MR protocol delivers increased throughput in single radio and two radio mesh networks compared to similar protocol with WCETT and MIC routing metrics. We also show that in the case of two radio mesh networks, our metric achieves good intra-path channel diversity.

Efficient routing on complex networks.

Abstract: We propose a routing strategy to improve the transportation efficiency on complex networks. Instead of using the routing strategy for shortest path, we give a generalized routing algorithm to find the so-called efficient path, which considers the possible congestion in the nodes along actual paths. Since the nodes with the largest degree are very susceptible to traffic congestion, an effective way to improve traffic and control congestion, as our strategy, can be redistributing traffic load in central nodes to other noncentral nodes. Simulation results indicate that the network capability in processing traffic is improved more than 10 times by optimizing the efficient path, which is in good agreement with the analysis.

An evaluation of inter-vehicle ad hoc networks based on realistic vehicular traces

Abstract: Vehicular ad hoc networks (VANETs) using WLAN tech-nology have recently received considerable attention. The evaluation of VANET routing protocols often involves simulators since management and operation of a large number of real vehicular nodes is expensive. We study the behavior of routing protocols in VANETs by using mobility information obtained from a microscopic vehicular traffic simulator that is based on the on the real road maps of Switzerland. The performance of AODV and GPSR is significantly in uenced by the choice of mobility model, and we observe a significantly reduced packet delivery ratio when employing the realistic traffic simulator to control mobility of nodes. To address the performance limitations of communication pro-tocols in VANETs, we investigate two improvements that increase the packet delivery ratio and reduce the delay until the first packet arrives. The traces used in this study are available for public download.

Routing and link-layer protocols for multi-channel multi-interface ad hoc wireless networks

Abstract: Wireless technologies, such as IEEE 802.11a, that are used in ad hoc networks provide for multiple non-overlapping channels. Most ad hoc network protocols that are currently available are designed to use a single channel. However, the available network capacity can be increased by using multiple channels. This paper presents new protocols specifically designed to exploit multiple channels. Our protocols simplify the use of multiple channels by using multiple interfaces, although the number of interfaces per host is typically smaller than the number of channels. We propose a link layer protocol to manage multiple channels, and it can be implemented over existing IEEE 802.11 hardware. We also propose a new routing metric for multi-channel multi-interface networks, and the metric is incorporated into an on-demand routing protocol that operates over the link layer protocol. Simulation results demonstrate the effectiveness of the proposed approach in significantly increasing network capacity, by utilizing all the available channels, even when the number of interfaces per host is smaller than the number of channels.

Real-time Power-Aware Routing in Sensor Networks

Abstract: Many wireless sensor network applications must resolve the inherent conflict between energy efficient communication and the need to achieve desired quality of service such as end-to-end communication delay. To address this challenge, we propose the Real-time Power-Aware Routing (RPAR) protocol, which achieves application-specified communication delays at low energy cost by dynamically adapting transmission power and routing decisions. RPAR features a power-aware forwarding policy and an efficient neighborhood manager that are optimized for resource-constrained wireless sensors. Moreover, RPAR addresses important practical issues in wireless sensor networks, including lossy links, scalability, and severe memory and bandwidth constraints. Simulations based on a realistic radio model of MICA2 motes show that RPAR significantly reduces the number of deadlines missed and energy consumption compared to existing real-time and energy-efficient routing protocols.

Multi-path TCP: a joint congestion control and routing scheme to exploit path diversity in the internet

Abstract: We consider the problem of congestion-aware multi-path routing in the Internet. Currently, Internet routing protocols select only a single path between a source and a destination. However, due to many policy routing decisions, single-path routing may limit the achievable throughput. In this paper, we envision a scenario where multi-path routing is enabled in the Internet to take advantage of path diversity. Using minimal congestion feedback signals from the routers, we present a class of algorithms that can be implemented at the sources to stably and optimally split the flow between each source-destination pair. We then show that the connection-level throughput region of such multi-path routing/congestion control algorithms can be larger than that of a single-path congestion control scheme.

Virtual ring routing: network routing inspired by DHTs

Abstract: This paper presents Virtual Ring Routing (VRR), a new network routing protocol that occupies a unique point in the design space. VRR is inspired by overlay routing algorithms in Distributed Hash Tables (DHTs) but it does not rely on an underlying network routing protocol. It is implemented directly on top of the link layer. VRR provides both raditional point-to-point network routing and DHT routing to the node responsible for a hash table key.VRR can be used with any link layer technology but this paper describes a design and several implementations of VRR that are tuned for wireless networks. We evaluate the performance of VRR using simulations and measurements from a sensor network and an 802.11a testbed. The experimental results show that VRR provides robust performance across a wide range of environments and workloads. It performs comparably to, or better than, the best wireless routing protocol in each experiment. VRR performs well because of its unique features: it does not require network flooding or trans-lation between fixed identifiers and location-dependent addresses.

Traffic dynamics based on local routing protocol on a scale-free network.

Abstract: We propose a packet routing strategy with a tunable parameter based on the local structural information of a scale-free network. As free traffic flow on the communication networks is key to their normal and efficient functioning, we focus on the network capacity that can be measured by the critical point of phase transition from free flow to congestion. Simulations show that the maximal capacity corresponds to alpha= -1 in the case of identical nodes' delivering ability. To explain this, we investigate the number of packets of each node depending on its degree in the free flow state and observe the power law behavior. Other dynamic properties including average packets traveling time and traffic load are also studied. Inspiringly, our results indicate that some fundamental relationships exist between the dynamics of synchronization and traffic on the scale-free networks.

DyXY: a proximity congestion-aware deadlock-free dynamic routing method for network on chip

Abstract: A novel routing algorithm, namely dynamic XY (DyXY) routing, is proposed for NoCs to provide adaptive routing and ensure deadlock-free and livelock-free routing at the same time.A new router architecture is developed to support the routing algorithm.Analytical models based on queuing theory are developed for DyXY routing for a two-dimensional mesh NoC architecture,and analytical results match very well with the simulation results.It is observed that DyXY routing can achieve better performance compared with static XY routing and odd-even routing.

Evaluating Mobility Pattern Space Routing for DTNs

Abstract: Because a delay tolerant network (DTN) can often be partitioned, routing is a challenge. However, routing benefits considerably if one can take advantage of knowledge concerning node mobility. This paper addresses this problem with a generic algorithm based on the use of a high-dimensional Euclidean space, that we call MobySpace, constructed upon nodes' mobility patterns. We provide here an analysis and a large scale evaluation of this routing scheme in the context of ambient networking by replaying real mobility traces. The specific MobySpace evaluated is based on the frequency of visits of nodes to each possible location. We show that routing based on MobySpace can achieve good performance compared to that of a number of standard algorithms, especially for nodes that are present in the network a large portion of the time. We determine that the degree of homogeneity of node mobility patterns has a high impact on routing. And finally, we study the ability of nodes to learn their own mobility patterns.

An energy-efficient ant-based routing algorithm for wireless sensor networks

Abstract: Wireless Sensor Networks are characterized by having specific requirements such as limited energy availability, low memory and reduced processing power. On the other hand, these networks have enormous potential applicability, e.g., habitat monitoring, medical care, military surveillance or traffic control. Many protocols have been developed for Wireless Sensor Networks that try to overcome the constraints that characterize this type of networks. Ant-based routing protocols can add a significant contribution to assist in the maximisation of the network lifetime, but this is only possible by means of an adaptable and balanced algorithm that takes into account the Wireless Sensor Networks main restrictions. This paper presents a new Wireless Sensor Network routing protocol, which is based on the Ant Colony Optimization metaheuristic. The protocol was studied by simulation for several Wireless Sensor Network scenarios and the results clearly show that it minimises communication load and maximises energy savings.

Performance analysis of mobility-assisted routing

Abstract: Traditionally, ad hoc networks have been viewed as a connected graph over which end-to-end routing paths had to be established.Mobility was considered a necessary evil that invalidates paths and needs to be overcome in an intelligent way to allow for seamless ommunication between nodes.However, it has recently been recognized that mobility an be turned into a useful ally, by making nodes carry data around the network instead of transmitting them. This model of routing departs from the traditional paradigm and requires new theoretical tools to model its performance. A mobility-assisted protocol forwards data only when appropriate relays encounter each other, and thus the time between such encounters, called hitting or meeting time, is of high importance.In this paper, we derive accurate closed form expressions for the expected encounter time between different nodes, under ommonly used mobility models. We also propose a mobility model that can successfully capture some important real-world mobility haracteristics, often ignored in popular mobility models, and alculate hitting times for this model as well. Finally, we integrate this results with a general theoretical framework that can be used to analyze the performance of mobility-assisted routing schemes. We demonstrate that derivative results oncerning the delay of various routing s hemes are very accurate, under all the mobility models examined. Hence, this work helps in better under-standing the performance of various approaches in different settings, and an facilitate the design of new, improved protocols.

ROFL: routing on flat labels

Abstract: It is accepted wisdom that the current Internet architecture conflates network locations and host identities, but there is no agreement on how a future architecture should distinguish the two. One could sidestep this quandary by routing directly on host identities themselves, and eliminating the need for network-layer protocols to include any mention of network location. The key to achieving this is the ability to route on flat labels. In this paper we take an initial stab at this challenge, proposing and analyzing our ROFL routing algorithm. While its scaling and efficiency properties are far from ideal, our results suggest that the idea of routing on flat labels cannot be immediately dismissed.

MIRO: multi-path interdomain routing

Abstract: The Internet consists of thousands of independent domains with different, and sometimes competing, business interests. However, the current interdomain routing protocol (BGP) limits each router to using a single route for each destination prefix, which may not satisfy the diverse requirements of end users. Recent proposals for source routing offer an alternative where end hosts or edge routers select the end-to-end paths. However, source routing leaves transit domains with very little control and introduces difficult scalability and security challenges. In this paper, we present a multi-path inter-domain routing protocol called MIRO that offers substantial flexiility, while giving transit domains control over the flow of traffic through their infrastructure and avoiding state explosion in disseminating reachability information. In MIRO, routers learn default routes through the existing BGP protocol, and arbitrary pairs of domains can negotiate the use of additional paths (bound to tunnels in the data plane) tailored to their special needs. MIRO retains the simplicity of BGP for most traffic, and remains backwards compatible with BGP to allow for incremental deployability. Experiments with Internet topology and routing data illustrate that MIRO offers tremendous flexibility for path selection with reasonable overhead.

On delivery guarantees of face and combined greedy-face routing in ad hoc and sensor networks

Abstract: It was recently reported that all known face and combined greedy-face routing variants cannot guarantee message delivery in arbitrary undirected planar graphs. The purpose of this article is to clarify that this is not the truth in general. We show that specifically in relative neighborhood and Gabriel graphs recovery from a greedy routing failure is always possible without changing between any adjacent faces. Guaranteed delivery then follows from guaranteed recovery while traversing the very first face. In arbitrary graphs, however, a proper face selection mechanism is of importance since recovery from a greedy routing failure may require visiting a sequence of faces before greedy routing can be restarted again. A prominent approach is to visit a sequence of faces which are intersected by the line connecting the source and destination node. Whenever encountering an edge which is intersecting with this line, the critical part is to decide if face traversal has to change to the next adjacent one or not. Failures may occur from incorporating face routing procedures that force to change the traversed face at each intersection. Recently observed routing failures which were produced by the GPSR protocol in arbitrary planar graphs result from incorporating such a face routing variant. They cannot be constructed by the well known GFG algorithm which does not force changing the face anytime. Beside methods which visit the faces intersected by the source destination line, we discuss face routing variants which simply restart face routing whenever the next face has to be explored. We give the first complete and formal proofs that several proposed face routing, and combined greedyface routing schemes do guarantee delivery in specific graph classes or even any arbitrary planar graphs. We also discuss the reasons why other methods may fail to deliver a message or even end up in a loop.

Provably Secure On-Demand Source Routing in Mobile Ad Hoc Networks

Abstract: Routing is one of the most basic networking functions in mobile ad hoc networks. Hence, an adversary can easily paralyze the operation of the network by attacking the routing protocol. This has been realized by many researchers and several "secure" routing protocols have been proposed for ad hoc networks. However, the security of those protocols has mainly been analyzed by informal means only. In this paper, we argue that flaws in ad hoc routing protocols can be very subtle, and we advocate a more systematic way of analysis. We propose a mathematical framework in which security can be precisely defined and routing protocols for mobile ad hoc networks can be proved to be secure in a rigorous manner. Our framework is tailored for on-demand source routing protocols, but the general principles are applicable to other types of protocols too. Our approach is based on the simulation paradigm, which has already been used extensively for the analysis of key establishment protocols, but, to the best of our knowledge, it has not been applied in the context of ad hoc routing so far. We also propose a new on-demand source routing protocol, called endairA, and we demonstrate the use of our framework by proving that it is secure in our model

Source selectable path diversity via routing deflections

Abstract: We present the design of a routing system in which end-systems set tags to select non-shortest path routes as an alternative to explicit source routes Routers collectively generate these routes by using tags as hints to independently deflect packets to neighbors that lie off the shortest-path We show how this can be done simply, by local extensions of the shortest path machinery, and safely, so that loops are provably not formed The result is to provide end-systems with a high-level of path diversity that allows them to bypass unde-sirable locations within the network Unlike explicit source routing, our scheme is inherently scalable and compatible with ISP policies because it derives from the deployed Internet routing We also sug-gest an encoding that is compatible with common IP usage, making our scheme incrementally deployable at the granularity of individual routers

Optimal transport on complex networks.

Abstract: We present a heuristic algorithm for the optimization of transport on complex networks. Previously proposed network transport optimization algorithms aim at avoiding or reducing link overload. Our algorithm balances traffic on a network by minimizing the maximum node betweenness with as little path lengthening as possible, thus being useful in cases when networks are jamming due to node congestion. By using the resulting routing, a network can sustain significantly higher traffic without jamming than in the case of shortest path routing.

Routing as a Service

Abstract: In Internet routing, there is a fundamental tussle between the end users who want control over the end-to-end paths and the Autonomous Systems (ASes) who want control over the flow of traffic through their infrastructure. To resolve this tussle and offer flexible routing control across multiple routing domains, we argue that customized route computation should be offered as a service by third-party providers. Outsourcing specialized route computation allows different path-selection mechanisms to coexist, and evolve over time.

SCAN: self-organized network-layer security in mobile ad hoc networks

Abstract: Protecting the network layer from malicious attacks is an important yet challenging security issue in mobile ad hoc networks. In this paper, we describe SCAN, a unified network-layer security solution for such networks that protects both routing and data forwarding operations through the same reactive approach. SCAN does not apply any cryptographic primitives on the routing messages. Instead, it protects the network by detecting and reacting to the malicious nodes. In SCAN, local neighboring nodes collaboratively monitor each other and sustain each other, while no single node is superior to the others. SCAN also adopts a novel credit strategy to decrease its overhead as time evolves. In essence, SCAN exploits localized collaboration and information cross-validation to protect the network in a self-organized manner. Through both analysis and simulation results, we demonstrate the effectiveness of SCAN even in a highly mobile and hostile environment.

Performance comparison of trust-based reactive routing protocols

Abstract: Ad hoc networks, due to their improvised nature, are frequently established in insecure environments and hence become susceptible to attacks. These attacks are launched by participating malicious nodes against different network services. Routing protocols, which act as the binding force in these networks, are a common target of these nodes. A number of secure routing protocols have recently been proposed, which make use of cryptographic algorithms to secure the routes. However, in doing so, these protocols entail a number of prerequisites during both the network establishment and operation phases. In contrast, trust-based routing protocols locate trusted rather than secure routes in the network by observing the sincerity in participation by other nodes. These protocols thus permit rapid deployment along with a dynamically adaptive operation, which conforms with the current network situation. In this paper, we evaluate the performance of three trust-based reactive routing protocols in a network with varying number of malicious nodes. With the help of exhaustive simulations, we demonstrate that the performance of the three protocols varies significantly even under similar attack, traffic, and mobility conditions. However, each trust-based routing protocol has its own peculiar advantage making it suitable for application in a particular extemporized environment.

Congestion Adaptive Routing in Mobile Ad Hoc Networks

Abstract: Mobility, channel error, and congestion are the main causes for packet loss in mobile ad hoc networks. Reducing packet loss typically involves congestion control operating on top of a mobility and failure adaptive routing protocol at the network layer. In the current designs, routing is not congestion-adaptive. Routing may let a congestion happen which is detected by congestion control, but dealing with congestion in this reactive manner results in longer delay and unnecessary packet loss and requires significant overhead if a new route is needed. This problem becomes more visible especially in large-scale transmission of heavy traffic such as multimedia data, where congestion is more probable and the negative impact of packet loss on the service quality is of more significance. We argue that routing should not only be aware of, but also be adaptive to, network congestion. Hence, we propose a routing protocol (CRP) with such properties. Our ns-2 simulation results confirm that CRP improves the packet loss rate and end-to-end delay while enjoying significantly smaller protocol overhead and higher energy efficiency as compared to AODV and DSR

An online heuristic for maximum lifetime routing in wireless sensor networks

Abstract: We show that the problem of routing messages in a wireless sensor network so as to maximize network lifetime is NP-hard. In our model, the online model, each message has to be routed without knowledge of future route requests. We also develop an online heuristic to maximize network lifetime. Our heuristic, which performs two shortest path computations to route each message, is superior to previously published heuristics for lifetime maximization - our heuristic results in greater lifetime and its performance is less sensitive to the selection of heuristic parameters. Additionally, our heuristic is superior on the capacity metric

Trust Establishment In Pure Ad-hoc Networks

Abstract: An ad-hoc network is a set of limited range wireless nodes that function in a cooperative manner so as to increase the overall range of the network. Each node in the network pledges to help its neighbours by passing packets to and fro, in return of a similar assurance from them. All is well if all participating nodes uphold such an altruistic behaviour. However, this is not always the case and often nodes are subjected to a variety of attacks by other nodes. These attacks range from naive passive eavesdropping to vicious battery draining attacks. Routing protocols, data, battery power and bandwidth are the common targets of these attacks. In order to overcome such attacks a number of routing protocols have been devised that use cryptographic algorithms to secure the routing mechanism, which in turn protects the other likely targets. A limiting requirement regarding these protocols is the reliance on an omnipresent, and often omniscient, trust authority. In our opinion, this reliance on a central entity is against the very nature of ad-hoc networks, which are supposed to be improvised and spontaneous. We present in this paper, a trust-based model for communication in ad-hoc networks that is based on individual experience rather than on a third party advocating trust levels. The model introduces the notion of belief and provides a dynamic measure of reliability and trustworthiness in pure ad-hoc networks.

A measurement study on the impact of routing events on end-to-end internet path performance

Abstract: Extensive measurement studies have shown that end-to-end Internet path performance degradation is correlated with routing dynamics. However, the root cause of the correlation between routing dynamics and such performance degradation is poorly understood. In particular, how do routing changes result in degraded end-to-end path performance in the first place? How do factors such as topological properties, routing policies, and iBGP configurations affect the extent to which such routing events can cause performance degradation? Answers to these questions are critical for improving network performance.In this paper, we conduct extensive measurement that involves both controlled routing updates through two tier-1 ISPs and active probes of a diverse set of end-to-end paths on the Internet. We find that routing changes contribute to end-to-end packet loss significantly. Specifically, we study failover events in which a link failure leads to a routing change and recovery events in which a link repair causes a routing change. In both cases, it is possible to experience data plane performance degradation in terms of increased long loss burst as well as forwarding loops. Furthermore, we find that common routing policies and iBGP configurations of ISPs can directly affect the end-to-end path performance during routing changes. Our work provides new insights into potential measures that network operators can undertake to enhance network performance.

Proposed routing for IEEE 802.11s WLAN mesh networks

Abstract: This paper describes the proposed routing for IEEE 802.11s WLAN mesh networks based on the current draft standard D0.01 from March 2006. IEEE 802.11s defines a new mesh data frame format and an extensibility framework for routing. The default routing protocol HWMP is described. HWMP is based on AODV and has a configurable extension for proactive routing towards so-called mesh portals. It uses MAC addresses (layer 2 routing) and uses a radio-aware routing metric for the calculation of paths. Furthermore, the optional routing protocol RA-OLSR is described.Note, that the standardization of WLAN Mesh Networking in IEEE 802.11s is work in progress during the time of writing. While the general concepts of the proposed routing protocols seem to be quite fixed, the details are likely to change.

Improved security in geographic ad hoc routing through autonomous position verification

Abstract: Inter-vehicle communication is regarded as one of the major applications of mobile ad hoc networks (MANETs). Compared to other MANETs, these so called vehicular ad hoc networks (VANETs) have special requirements in terms of node mobility and position-dependent applications, which are well met by geographic routing protocols. Functional research on geographic routing has already reached a considerable level, whereas security aspects have been vastly neglected so far. Since position dissemination is crucial for geographic routing, forged position information has severe impact regarding both performance and security.In order to lessen this problem, we propose a detection mechanism that is capable of recognizing nodes cheating about their position in beacons (periodic position dissemination in most single-path geographic routing protocols, e.g. GPSR). Unlike other proposals described in the literature, our detection does not rely on additional hardware or special nodes, which contradicts the ad hoc approach. Instead, this mechanism uses a number of different independent sensors to quickly give an estimation of the trustworthiness of other nodes' position claims without using dedicated infrastructure or specialized hardware.The simulative evaluation proves that our position verification system successfully discloses nodes disseminating false positions and thereby widely prevents attacks using position cheating.