Showing papers on "Wireless Routing Protocol published in 2011"

Routing in cognitive radio networks: Challenges and solutions

Abstract: Cognitive radio networks (CRNs) are composed of cognitive, spectrum-agile devices capable of changing their configurations on the fly based on the spectral environment. This capability opens up the possibility of designing flexible and dynamic spectrum access strategies with the purpose of opportunistically reusing portions of the spectrum temporarily vacated by licensed primary users. On the other hand, the flexibility in the spectrum access phase comes with an increased complexity in the design of communication protocols at different layers. This work focuses on the problem of designing effective routing solutions for multi-hop CRNs, which is a focal issue to fully unleash the potentials of the cognitive networking paradigm. We provide an extensive overview of the research in the field of routing for CRNs, clearly differentiating two main categories: approaches based on a full spectrum knowledge, and approaches that consider only local spectrum knowledge obtained via distributed procedures and protocols. In each category we describe and comment on proposed design methodologies, routing metrics and practical implementation issues. Finally, possible future research directions are also proposed.

EBRP: Energy-Balanced Routing Protocol for Data Gathering in Wireless Sensor Networks

Abstract: Energy is an extremely critical resource for battery-powered wireless sensor networks (WSN), thus making energy-efficient protocol design a key challenging problem. Most of the existing energy-efficient routing protocols always forward packets along the minimum energy path to the sink to merely minimize energy consumption, which causes an unbalanced distribution of residual energy among sensor nodes, and eventually results in a network partition. In this paper, with the help of the concept of potential in physics, we design an Energy-Balanced Routing Protocol (EBRP) by constructing a mixed virtual potential field in terms of depth, energy density, and residual energy. The goal of this basic approach is to force packets to move toward the sink through the dense energy area so as to protect the nodes with relatively low residual energy. To address the routing loop problem emerging in this basic algorithm, enhanced mechanisms are proposed to detect and eliminate loops. The basic algorithm and loop elimination mechanism are first validated through extensive simulation experiments. Finally, the integrated performance of the full potential-based energy-balanced routing algorithm is evaluated through numerous simulations in a random deployed network running event-driven applications, the impact of the parameters on the performance is examined and guidelines for parameter settings are summarized. Our experimental results show that there are significant improvements in energy balance, network lifetime, coverage ratio, and throughput as compared to the commonly used energy-efficient routing algorithm.

Social-aware stateless forwarding in pocket switched networks

Abstract: In this paper we describe SANE, the first forwarding mechanism that combines the advantages of both social-aware and stateless approaches in pocket switched network routing. SANE is based on the observation“that we validate on real-world traces”that individuals with similar interests tend to meet more often. In our approach, individuals (network members) are characterized by their interest profile, a compact representation of their interests. Through extensive experiments, we show the superiority of social-aware, stateless forwarding over existing stateful, social-aware and stateless, social-oblivious forwarding. An important byproduct of our interest-based approach is that it easily enables innovative routing primitives, such as interest-casting. An interest-casting protocol is also described, and extensively evaluated through experiments based on both real-world and synthetic mobility traces.

Intersection-Based Geographical Routing Protocol for VANETs: A Proposal and Analysis

Abstract: This paper presents a class of routing protocols for vehicular ad hoc networks (VANETs) called the Intersection-based Geographical Routing Protocol (IGRP), which outperforms existing routing schemes in city environments. IGRP is based on an effective selection of road intersections through which a packet must pass to reach the gateway to the Internet. The selection is made in a way that guarantees, with high probability, network connectivity among the road intersections while satisfying quality-of-service (QoS) constraints on tolerable delay, bandwidth usage, and error rate. Geographical forwarding is used to transfer packets between any two intersections on the path, reducing the path's sensitivity to individual node movements. To achieve this, we mathematically formulate the QoS routing problem as a constrained optimization problem. Specifically, analytical expressions for the connectivity probability, end-to-end delay, hop count, and bit error rate (BER) of a route in a two-way road scenario are derived. Then, we propose a genetic algorithm to solve the optimization problem. Numerical and simulation results show that the proposed approach gives optimal or near-optimal solutions and significantly improves VANET performance when compared with several prominent routing protocols, such as greedy perimeter stateless routing (GPSR), greedy perimeter coordinator routing (GPCR), and optimized link-state routing (OLSR).

Multipath optimized link state routing for mobile ad hoc networks

Abstract: Multipath routing protocols for Mobile Ad hoc NETwork (MANET) address the problem of scalability, security (confidentiality and integrity), lifetime of networks, instability of wireless transmissions, and their adaptation to applications. Our protocol, called MultiPath OLSR (MP-OLSR), is a multipath routing protocol based on OLSR [1]. The Multipath Dijkstra Algorithm is proposed to obtain multiple paths. The algorithm gains great flexibility and extensibility by employing different link metrics and cost functions. In addition, route recovery and loop detection are implemented in MP-OLSR in order to improve quality of service regarding OLSR. The backward compatibility with OLSR based on IP source routing is also studied. Simulation based on Qualnet simulator is performed in different scenarios. A testbed is also set up to validate the protocol in real world. The results reveal that MP-OLSR is suitable for mobile, large and dense networks with large traffic, and could satisfy critical multimedia applications with high on time constraints.

From MANET To IETF ROLL Standardization: A Paradigm Shift in WSN Routing Protocols

Abstract: In large networks, a data source may not reach the intended sink in a single hop, thereby requiring the traffic to be routed via multiple hops. An optimized choice of such routing path is known to significantly increase the performance of said networks. This holds particularly true for wireless sensor networks (WSNs) consisting of a large amount of miniaturized battery-powered wireless networked sensors required to operate for years with no human intervention. There has hence been a growing interest on understanding and optimizing WSN routing and networking protocols in recent years, where the limited and constrained resources have driven research towards primarily reducing energy consumption, memory requirements and complexity of routing functionalities. To this end, early flooding-based and hierarchical protocols have migrated within the past decade to geographic and self-organizing coordinate-based routing solutions. The former have been brought to standardization through the Internet Engineering Task Force (IETF) Mobile Ad-hoc Networks (MANET) working group; the latter are currently finding their way into standardization through the IETF Routing Over Low power and Lossy networks (ROLL) working group. This article thus surveys this paradigm shift for routing in WSNs and, unlike previous milestone surveys, follows a rather chronological organization within the given protocol taxonomy. For each protocol family, we provide a didactic presentation of the basic concept, a discussion on the enhancements and variants on that concept, and a detailed description of the latest state-of-the-art protocols of that family. We believe that this organization sheds some light on the design choices of emerging IETF ROLL protocols and also provides design parameters of interest to the WSN engineer, essentially enabling the design and implementation of more reliable and efficient WSN solutions.

Mobility-based clustering protocol for wireless sensor networks with mobile nodes

Abstract: In this study, the authors propose a mobility-based clustering (MBC) protocol for wireless sensor networks with mobile nodes. In the proposed clustering protocol, a sensor node elects itself as a cluster-head based on its residual energy and mobility. A non-cluster-head node aims at its link stability with a cluster head during clustering according to the estimated connection time. Each non-cluster-head node is allocated a timeslot for data transmission in ascending order in a time division multiple address (TDMA) schedule based on the estimated connection time. In the steady-state phase, a sensor node transmits its sensed data in its timeslot and broadcasts a joint request message to join in a new cluster and avoid more packet loss when it has lost or is going to lose its connection with its cluster head. Simulation results show that the MBC protocol can reduce the packet loss by 25% compared with the cluster-based routing (CBR) protocol and 50% compared with the low-energy adaptive clustering hierarchy-mobile (LEACH-mobile) protocol. Moreover, it outperforms both the CBR protocol and the LEACH-mobile protocol in terms of average energy consumption and average control overhead, and can better adapt to a highly mobile environment.

Energy-aware evolutionary routing protocol for dynamic clustering of wireless sensor networks

Abstract: The main challenges in designing and planning the operations of Wireless Sensor Networks (WSNs) are to optimize energy consumption and prolong network lifetime. Cluster-based routing techniques, such as the well-known low-energy adaptive clustering hierarchy (LEACH), are used to achieve scalable solutions and extend the network lifetime until the last node dies (LND). Also, evolutionary algorithms (EAs), have been successfully used in recent years as meta-heuristics to address energy-aware routing challenges by designing intelligent models that collaborate together to optimize an appropriate energy-aware objective function. On the other hand, some protocols, such as stable election protocol (SEP), are concerned with another objective: extending the stability time until the first node dies (FND). Often, there is a tradeoff between extending the time until FND and the time until LND. To our knowledge, no attempt has been made to obtain a better compromise between the stability time and network lifetime. This paper reformulates the design of the most important characteristic of the EA (i.e., the objective function), so as to obtain a routing protocol that can provide more robust results than the existing heuristic and meta-heuristic protocols in terms of network stability period, lifetime, and energy consumption. An evolutionary-based routing protocol is proposed, which can guarantee better tradeoff between the lifespan and the stability period of the network with efficient energy utilization. To support this claim, extensive simulations on 90 homogeneous and heterogeneous WSN models are evaluated and compared against the LEACH, SEP, and one of the existing evolutionary-based routing protocols, hierarchical clustering-algorithm-based genetic algorithm (HCR).

A critical evaluation of the IPv6 Routing Protocol for Low Power and Lossy Networks (RPL)

Abstract: With RPL - the “IPv6 Routing Protocol for Low-power Lossy Networks” - emerging as a Proposed Standard “Request For Comment” (RFC) in the Internet Engineering Task Force (IETF) after a ∼2-year development cycle, this paper presents a critical evaluation of the resulting protocol and its applicability and limits. The paper presents a selection of observations of the protocol characteristics, exposes experiences acquired when producing a prototype implementation of RPL, and presents results obtained from testing this protocol - both in a network simulator, and in real-world experiments on a wireless sensor network testbed. The paper aims at providing a better understanding of possible weaknesses and limits of RPL, notably the possible directions that further protocol developments should explore, in order to address these.

A Survey on Routing Protocols for Large-Scale Wireless Sensor Networks

Abstract: With the advances in micro-electronics, wireless sensor devices have been made much smaller and more integrated, and large-scale wireless sensor networks (WSNs) based the cooperation among the significant amount of nodes have become a hot topic. “Large-scale” means mainly large area or high density of a network. Accordingly the routing protocols must scale well to the network scope extension and node density increases. A sensor node is normally energy-limited and cannot be recharged, and thus its energy consumption has a quite significant effect on the scalability of the protocol. To the best of our knowledge, currently the mainstream methods to solve the energy problem in large-scale WSNs are the hierarchical routing protocols. In a hierarchical routing protocol, all the nodes are divided into several groups with different assignment levels. The nodes within the high level are responsible for data aggregation and management work, and the low level nodes for sensing their surroundings and collecting information. The hierarchical routing protocols are proved to be more energy-efficient than flat ones in which all the nodes play the same role, especially in terms of the data aggregation and the flooding of the control packets. With focus on the hierarchical structure, in this paper we provide an insight into routing protocols designed specifically for large-scale WSNs. According to the different objectives, the protocols are generally classified based on different criteria such as control overhead reduction, energy consumption mitigation and energy balance. In order to gain a comprehensive understanding of each protocol, we highlight their innovative ideas, describe the underlying principles in detail and analyze their advantages and disadvantages. Moreover a comparison of each routing protocol is conducted to demonstrate the differences between the protocols in terms of message complexity, memory requirements, localization, data aggregation, clustering manner and other metrics. Finally some open issues in routing protocol design in large-scale wireless sensor networks and conclusions are proposed.

Routing Protocols in Mobile Ad-hoc Networks \

Abstract: A Mobile Ad Hoc Networks (MANETs) is a group of mobile nodes which cooperate in forwarding packets in a multi-hop fashion without any centralized administration. One of its key challenges is routing. Many routing protocols for MANET have been proposed and the protocols can be classified as proactive routing and on demand routing protocols. This paper uses ns-2 as the simulation tool, 802.11 as the wireless MAC protocol, and AODV & DSDV as the routing protocol. We present the traces of communication between different mobile nodes using Routing Protocols in MANETs. To compare the performance of Proactive and Reactive routing protocol, we have to analyze the simulation results by graphical manner and trace file based on QoS metrics such as Throughput, Drop, Delay, Jitter etc. Here, we have analyzed the simulation result by traces files only. The performance differentials have been analyzed based on network load, mobility, and network size. INDEX TERMS DSDV, AODV, MANET, QoS, Network Simulator-2 (NS2).

Performance analysis of the RPL Routing Protocol

Abstract: The IETF Routing Over Low-power and Lossy Networks working group has recently proposed the IPv6 Routing Protocol for Low power and Lossy Networks, i.e., the RPL protocol. It has been designed to face the typical requirements of wireless sensor networks. Given its relevance in the industrial and scientific communities, this paper presents a performance analysis of RPL based on simulations. Our results clearly show that RPL can ensure a very fast network set-up, thus allowing the development of advanced monitoring applications also in critical conditions. On the other hand, we found that further research is required to optimize the RPL signaling in order to decrease the protocol overhead.

Data-centric multiobjective QoS-aware routing protocol for body sensor networks.

Abstract: In this paper, we address Quality-of-Service (QoS)-aware routing issue for Body Sensor Networks (BSNs) in delay and reliability domains. We propose a data-centric multiobjective QoS-Aware routing protocol, called DMQoS, which facilitates the system to achieve customized QoS services for each traffic category differentiated according to the generated data types. It uses modular design architecture wherein different units operate in coordination to provide multiple QoS services. Their operation exploits geographic locations and QoS performance of the neighbor nodes and implements a localized hop-by-hop routing. Moreover, the protocol ensures (almost) a homogeneous energy dissipation rate for all routing nodes in the network through a multiobjective Lexicographic Optimization-based geographic forwarding. We have performed extensive simulations of the proposed protocol, and the results show that DMQoS has significant performance improvements over several state-of-the-art approaches.

A Comparative Study of Various Routing Protocols in VANET

Abstract: Vehicular Ad Hoc Networks (VANET) is a subclass of Mobile ad hoc networks which provides a distinguished approach for Intelligent Transport System (ITS) The survey of routing protocols in VANET is important and necessary for smart ITS T his paper discusses the advantages / disadvantages and the applications of various routing protocols for vehicular ad hoc networks It explores the motivation behind the designed, and traces the evolution of these routing protocols F inally the paper concludes by a tabular comparison of the various routing protocols for VANET

The evolution of a DTN routing protocol - PRoPHETv2

Abstract: Research within Delay- and Disruption Tolerant Networks (DTN) has evolved into a mature research area. PRoPHET is a routing protocol for DTNs that was developed when DTN research was in its infancy and which has been studied by many. In this paper we investigate how the protocol can evolve to meet new challenges that has been identified through research and practical experience. We propose some minor modifications to the routing metric calculations done in PRoPHET which has potential to alleviate some issues and improve the performance of the protocol. Using these modifications, we define an updated version of the protocol called PRoPHETv2. We run simulations to verify the operation of the protocol and compare its performance against the original version of the protocol as well as some other routing protocols. The evaluations are done using both traces from an existing DTN deployment and a synthetic mobility model. Since the basic mechanisms of the protocol remain the same, migrating existing implementations to the new version of PRoPHET is possible with limited effort.

EEDBR: Energy-Efficient Depth-Based Routing Protocol for Underwater Wireless Sensor Networks

Abstract: Recently, Underwater Wireless Sensor Networks (UWSNs) have attracted much research attention from both academia and industry, in order to explore the vast underwater environment However, designing network protocols is challenging in UWSNs since UWSNs have peculiar characteristics of large propagation delay, high error rate, low bandwidth and limited energy In UWSNs, improving the energy efficiency is one of the most important issues since the replacement of the batteries of such nodes is very expensive due to harsh underwater environment Hence, in this paper, we propose an energy efficient routing protocol, named EEDBR (Energy-Efficient Depth Based Routing protocol) for UWSNs Our proposed protocol utilizes the depth of the sensor nodes for forwarding the data packets Furthermore, the residual energy of the sensor nodes is also taken into account in order to improve the network life-time Based on the comprehensive simulation using NS2, we observe that our proposed routing protocol contributes to the performance improvements in terms of the network lifetime, energy consumption and end-to-end delay

Evaluating the Performance of RPL and 6LoWPAN in TinyOS

Abstract: Responding to the increasing interest to connect wireless sensor networks (WSN) to the Internet, the IETF has proposed standards that enable IPv6-based sensor networks. Specifically, the IETF 6LoWPAN and RoLL working groups developed standards for encapsulating IPv6 datagrams in 802.15.4 frames, neighbor discovery, and routing that allow sensor networks to exchange IPv6 datagrams with Internet hosts. However, given that these standards, especially the RPL routing protocol, are relatively new, there has not yet been a study that measures the actual performance of these proposals using real implementations. In this work, we use the BLIP and TinyRPL implementations in TinyOS 2.x to evaluate the performance of the newly proposed standards and compare them with CTP, the de-facto routing protocol standard for TinyOS. Our results indicate that the performance of TinyRPL is comparable with CTP and at the same time, TinyRPL can provide additional functionalities that traditional WSN routing protocols could not provide. We also discovered several issues, relevant to system developers and the standardization groups, which can enhance the proposed standards’ performance.

An Acknowledgement-Based Approach for the Detection of Routing Misbehaviour in MANETS

Abstract: We are considering the Routing misbehavior in MANETs (Mobile Ad Hoc Networks). Routing protocols for MANETs are based on the assumption which are, all participating nodes are fully cooperative. But, due to the open structure node misbehaviors may exist. One such routing misbehavior is that some nodes will take part in the route discovery and maintenance processes but refuse to forward data packets. In this, we propose the 2ACK scheme that serves as an add-on technique for routing schemes to detect routing misbehavior and to mitigate their effect. The basic idea of the 2ACK scheme is to send two-hop acknowledgment packets in the opposite direction of the routing path. To reduce extra routing overhead, only a few of the received data packets are acknowledged in the 2ACK scheme.

Geographical Routing With Location Service in Intermittently Connected MANETs

Abstract: Combining mobile platforms such as manned or unmanned vehicles and peer-assisted wireless communication is an enabler for a vast number of applications. A key enabler for the applications is the routing protocol that directs the packets in the network. Routing packets in fully connected mobile ad hoc networks (MANETs) has been studied to a great extent, but the assumption on full connectivity is generally not valid in a real system. This case means that a practical routing protocol must handle intermittent connectivity and the absence of end-to-end connections. In this paper, we propose a geographical routing algorithm called location-aware routing for delay-tolerant networks (LAROD), enhanced with a location service, location dissemination service (LoDiS), which together are shown to suit an intermittently connected MANET (IC-MANET). Because location dissemination takes time in IC-MANETs, LAROD is designed to route packets with only partial knowledge of geographic position. To achieve low overhead, LAROD uses a beaconless strategy combined with a position-based resolution of bids when forwarding packets. LoDiS maintains a local database of node locations, which is updated using broadcast gossip combined with routing overhearing. The algorithms are evaluated under a realistic application, i.e., unmanned aerial vehicles deployed in a reconnaissance scenario, using the low-level packet simulator ns-2. The novelty of this paper is the illustration of sound design choices in a realistic application, with holistic choices in routing, location management, and the mobility model. This holistic approach justifies that the choice of maintaining a local database of node locations is both essential and feasible. The LAROD-LoDiS scheme is compared with a leading delay-tolerant routing algorithm (spray and wait) and is shown to have a competitive edge, both in terms of delivery ratio and overhead. For spray and wait, this case involved a new packet-level implementation in ns-2 as opposed to the original connection-level custom simulator.

Model and Protocol for Energy-Efficient Routing over Mobile Ad Hoc Networks

Abstract: Many minimum energy (energy-efficient) routing protocols have been proposed in recent years. However, very limited effort has been made in studying routing overhead, route setup time, and route maintenance issues associated with these protocols. Without a careful design, an energy-efficient routing protocol can perform much worse than a normal routing protocol. In this paper, we first show that the minimum energy routing schemes in the literature could fail without considering the routing overhead involved and node mobility. We then propose a more accurate analytical model to track the energy consumptions due to various factors, and a simple energy-efficient routing scheme PEER to improve the performance during path discovery and in mobility scenarios. Our simulation results indicate that compared to a conventional energy-efficient routing protocol, PEER protocol can reduce up to 2/3 path discovery overhead and delay, and 50 percent transmission energy consumption.

Improvement in LEACH protocol for large-scale wireless sensor networks

Abstract: As the use of wireless sensor networks (WSNs) has grown enormously in the past few decades, the need of scalable & energy efficient routing and data aggregation protocol for large-scale deployments has also risen. LEACH is a hierarchical clustering protocol that provides an elegant solution for such protocols. One deficiency that affects the performance of the protocol is existence of very large and very small clusters in the network at the same time. This leads to the decrease in lifetime of WSNs. In this paper, we propose and analyze a new energy efficient clustering protocol (FZ-LEACH) that eliminates the above problem by forming Far-Zone. Far-Zone is a group of sensor nodes which are placed at locations where their energies are less than a threshold. The simulation results and analysis show that proposed FZ-LEACH algorithm outperforms LEACH in terms of energy consumption and network lifetime.

Cluster Based Routing Protocol for Mobile Nodes in Wireless Sensor Network

Abstract: Mobility of sensor nodes in wireless sensor network (WSN) has posed new challenges particularly in packet delivery ratio and energy consumption. Some real applications impose combined environments of fixed and mobile sensor nodes in the same network, while others demand a complete mobile sensors environment. Packet loss that occurs due to mobility of the sensor nodes is one of the main challenges which comes in parallel with energy consumption. In this paper, we use cross layer design between medium access control (MAC) and network layers to overcome these challenges. Thus, a cluster based routing protocol for mobile sensor nodes (CBR-Mobile) is proposed. The CBR-Mobile is mobility and traffic adaptive protocol. The timeslots assigned to the mobile sensor nodes that had moved out of the cluster or have not data to send will be reassigned to incoming sensor nodes within the cluster region. The protocol introduces two simple databases to achieve the mobility and traffic adaptively. The proposed protocol sends data to cluster heads in an efficient manner based on received signal strength. In CBR-Mobile protocol, cluster based routing collaborates with hybrid MAC protocol to support mobility of sensor nodes. Schedule timeslots are used to send the data message while the contention timeslots are used to send join registration messages. The performance of proposed CBR-Mobile protocol is evaluated using MATLAB and was observed that the proposed protocol improves the packet delivery ratio, energy consumption, delay and fairness in mobility environment compared to LEACH-Mobile and AODV protocols.

Wireless sensor network with energy efficient protocols

Abstract: The wireless sensor network with energy efficient protocols includes a network of external sensors in communication with a data sink. The network utilizes an algorithm integrating a modified S-MAC (an algorithm for medium access control) protocol for decreasing energy usage in operating the node and associated sensors. A routing protocol is further integrated into the algorithm, the routing protocol being based upon cluster head rotation.

Ubiquitous data collection for mobile users in wireless sensor networks

Abstract: We study the ubiquitous data collection for mobile users in wireless sensor networks. People with handheld devices can easily interact with the network and collect data. We propose a novel approach for mobile users to collect the network-wide data. The routing structure of data collection is additively updated with the movement of the mobile user. With this approach, we only perform a local modification to update the routing structure while the routing performance is bounded and controlled compared to the optimal performance. The proposed protocol is easy to implement. Our analysis shows that the proposed approach is scalable in maintenance overheads, performs efficiently in the routing performance, and provides continuous data delivery during the user movement. We implement the proposed protocol in a prototype system and test its feasibility and applicability by a 49-node testbed. We further conduct extensive simulations to examine the efficiency and scalability of our protocol with varied network settings.

Review of Various Routing Protocols for MANETs

Abstract: In recent years, a vast research has been seen going on in the field of Mobile Ad Hoc Networks (MANETs). Due to limited resources in MANETs, to design an efficient and reliable routing strategy is still a challenge. An intelligent routing strategy is required to efficiently use the limited resources. Also the algorithms designed for traditional wired networks such as link-state or distance vector, does not scale well in wireless environment. Routing in MANETs is a challenging task and has received a tremendous amount of attention from researchers around the world. To overcome this problem a number of routing protocols have been developed and the number is still increasing day by day. It is quite difficult to determine which protocols may perform well under a number of different network scenarios such as network size and topology etc. In this paper we provide an overview of a wide range of the existing routing protocols with a particular focus on their characteristics and functionality. Also, the comparison is provided based on the routing methodologies and information used to make routing decisions. The performance of all the routing protocols is also discussed. Further this study will help the researchers to get an overview of the existing protocols and suggest which protocols may perform better with respect to varying network scenarios.

Connectivity-aware minimum-delay geographic routing with vehicle tracking in VANETs

Abstract: In this paper, we propose the connectivity-aware minimum-delay geographic routing (CMGR) protocol for vehicular ad hoc networks (VANETs), which adapts well to continuously changing network status in such networks. When the network is sparse, CMGR takes the connectivity of routes into consideration in its route selection logic to maximize the chance of packet reception. On the other hand, in situations with dense network nodes, CMGR determines the routes with adequate connectivity and selects among them the route with the minimum delay. The performance limitations of CMGR in special vehicular networking situations are studied and addressed. These situations, which include the case where the target vehicle has moved away from its expected location and the case where traffic in a road junction is so sparse that no next-hop vehicle can be found on the intended out-going road, are also problematic in most routing protocols for VANETs. Finally, the proposed protocol is compared with two plausible geographic connectivity-aware routing protocols for VANETs, A-STAR and VADD. The obtained results show that CMGR outperforms A-STAR and VADD in terms of both packet delivery ratio and ratio of dropped data packets. For example, under the specific conditions considered in the simulations, when the maximum allowable one-way transmission delay is 1min and one gateway is deployed in the network, the packet delivery ratio of CMGR is approximately 25% better than VADD and A-STAR for high vehicle densities and goes up to 900% better for low vehicle densities.