Showing papers in "IEEE Communications Surveys and Tutorials in 2005"

A survey and comparison of peer-to-peer overlay network schemes

Abstract: Over the Internet today, computing and communications environments are significantly more complex and chaotic than classical distributed systems, lacking any centralized organization or hierarchical control. There has been much interest in emerging Peer-to-Peer (P2P) network overlays because they provide a good substrate for creating large-scale data sharing, content distribution, and application-level multicast applications. These P2P overlay networks attempt to provide a long list of features, such as: selection of nearby peers, redundant storage, efficient search/location of data items, data permanence or guarantees, hierarchical naming, trust and authentication, and anonymity. P2P networks potentially offer an efficient routing architecture that is self-organizing, massively scalable, and robust in the wide-area, combining fault tolerance, load balancing, and explicit notion of locality. In this article we present a survey and comparison of various Structured and Unstructured P2P overlay networks. We categorize the various schemes into these two groups in the design spectrum, and discuss the application-level network performance of each group.

A survey of clustering schemes for mobile ad hoc networks

Abstract: Clustering is an important research topic for mobile ad hoc networks (MANETs) because clustering makes it possible to guarantee basic levels of system performance, such as throughput and delay, in the presence of both mobility and a large number of mobile terminals. A large variety of approaches for ad hoc clustering have been presented, whereby different approaches typically focus on different performance metrics. This article presents a comprehensive survey of recently proposed clustering algorithms, which we classify based on their objectives. This survey provides descriptions of the mechanisms, evaluations of their performance and cost, and discussions of advantages and disadvantages of each clustering scheme. With this article, readers can have a more thorough and delicate understanding of ad hoc clustering and the research trends in this area.

Secure routing for mobile ad hoc networks

Abstract: In this paper we present a survey of secure ad hoc routing protocols for mobile wireless networks. A mobile ad hoc network is a collection of nodes that is connected through a wireless medium forming rapidly changing topologies. The widely accepted existing routing protocols designed to accommodate the needs of such self-organized networks do not address possible threats aiming at the disruption of the protocol itself. The assumption of a trusted environment is not one that can be realistically expected; hence several efforts have been made towards the design of a secure and robust routing protocol for ad hoc networks. We briefly present the most popular protocols that follow the table-driven and the source-initiated on-demand approaches. Based on this discussion we then formulate the threat model for ad hoc routing and present several specific attacks that can target the operation of a protocol. In order to analyze the proposed secure ad hoc routing protocols in a structured way we have classified them into five categories; solutions based on asymmetric cryptography, solutions based on symmetric cryptography, hybrid solutions, reputation-based solutions and a category of add-on mechanisms that satisfy specific security requirements. A comparison between these solutions can provide the basis for future research in this rapidly evolving area.

A survey of security issues in mobile ad hoc and sensor networks

Abstract: Security in mobile ad hoc networks is difficult to achieve, notably because of the vulnerability of wireless links, the limited physical protection of nodes, the dynamically changing topology, the absence of a certification authority, and the lack of a centralized monitoring or management point. Earlier studies on mobile ad hoc networks (MANETs) aimed at proposing protocols for some fundamental problems, such as routing, and tried to cope with the challenges imposed by the new environment. These protocols, however, fully trust all nodes and do not consider the security aspect. They are consequently vulnerable to attacks and misbehavior. More recent studies focused on security problems in MANETs, and proposed mechanisms to secure protocols and applications. This article surveys these studies. It presents and discusses several security problems along with the currently proposed solutions (as of July 2005) at different network layers of MANETs. Security issues involved in this article include routing and data forwarding, medium access, key management and intrusion detection systems (IDSs). This survey also includes an overview of security in a particular type of MANET, namely, wireless sensor networks (WSNs).

Using game theory to analyze wireless ad hoc networks

Abstract: The application of mathematical analysis to the study of wireless ad hoc networks has met with limited success due to the complexity of mobility and traffic models, the dynamic topology, and the unpredictability of link quality that characterize such networks. The ability to model individual, independent decision makers whose actions potentially affect all other decision makers renders game theory particularly attractive to analyze the performance of ad hoc networks. In this article we describe how various interactions in wireless ad hoc networks can be modeled as a game. This allows the analysis of existing protocols and resource management schemes, as well as the design of equilibrium-inducing mechanisms that provide incentives for individual users to behave in socially-constructive ways. We survey the recent literature on game theoretic analysis of ad hoc networks, highlighting its applicability to power control and waveform adaptation, medium access control, routing, and node participation, among others.

Broadband communications via high-altitude platforms: a survey

Abstract: This article is a survey on communication aspects of High Altitude Platforms (HAPs), namely airships or aircraft positioned in the stratosphere between 17 and 22 km. HAPs can be considered as a novel solution for providing telecommunications services. This survey begins with an introduction to HAPs, that is, some historical information and advantages of HAPs compared to terrestrial and satellite networks, followed by information about suitable airships and aircraft, frequency bands allocated to HAPs, possible architectures, and some points on the system structure. We continue with the studies that have been carried out on channel modeling and interference, antennas, transmission and coding techniques. We also refer to access and resource allocation techniques that have been performed so far. Finally, the survey concludes with the types of applications that HAPs are suitable for, in addition to some related projects.

Call admission control in wireless networks: a comprehensive survey

Abstract: Radio resource management (RRM) plays a major role in Quality of Service (QoS) provisioning for wireless communication systems. The performance of RRM techniques has a direct impact on each user's individual performance and on the overall network performance. Arriving (new and handoff) calls are granted/denied access to the network by the call admission scheme (CAC) based on predefined criteria, taking the network loading conditions into consideration. CAC in wireless networks has been receiving a great deal of attention during the last two decades due to the growing popularity of wireless communications and the central role that CAC plays in QoS provisioning in terms of the signal quality, call blocking and dropping probabilities, packet delay and loss rate, and transmission rate. In the first and second generation of wireless systems, CAC has been developed for a single service environment. In the third generation and beyond wireless systems, multimedia services such as voice, video, data, and audio are to be offered with various QoS profiles. Hence, more sophisticated CAC schemes are developed to cope with these changes. This article provides a comprehensive survey of CAC schemes in modern wireless networks.

A survey of TCP over ad hoc networks

Abstract: The Transmission Control Protocol (TCP) was designed to provide reliable end-to-end delivery of data over unreliable networks. In practice, most TCP deployments have been carefully designed in the context of wired networks. Ignoring the properties of wireless ad hoc networks can lead to TCP implementations with poor performance. In order to adapt TCP to the ad hoc environment, improvements have been proposed in the literature to help TCP to differentiate between the different types of losses. Indeed, in mobile or static ad hoc networks losses are not always due to network congestion, as it is mostly the case in wired networks. In this report, we present an overview of this issue and a detailed discussion of the major factors involved. In particular, we show how TCP can be affected by mobility and lower-layer protocols. In addition, we survey the main proposals that are intended to adapting TCP to mobile and static ad hoc environments.

Handover management architectures in integrated WLAN/cellular networks

Abstract: The integration of existing cellular systems with new wireless access technologies, such as wireless LANs, has attracted considerable attention during the past few years. The challenges to be addressed include authentication, security, QoS support, and mobility management. Efficient mobility management, and especially handover management, is considered one of the major factors toward a seamless provision of multimedia applications across networks of different technologies. A large number of solutions have been proposed in an attempt to tackle all relevant technical issues concerning handover management. In order to evaluate these solutions, a more systematic categorization is needed. This survey gives an overview of the most recent handover management architectures for integrated WLAN/Cellular networks, focusing mainly on 802.11-based WLANs and GPRS/UMTS cellular networks. The various proposals are categorized based on the point of system integration, their main characteristics are presented, and their advantages and shortcomings are discussed in an overall evaluation section.

On the building blocks of quality of service in heterogeneous IP networks

Abstract: After more than a decade of active research on Quality of Service in IP networks and the Internet, the majority of IP traffic relies on the conventional best-effort IP service model. Nevertheless, some QoS mechanisms are deployed in current networking infrastructures, while emerging applications pose QoS challenges. This survey brings into the foreground a broad range of research results on Quality of Service in IP-based networks. First, a justification of the need for QoS is provided, along with challenges stemming from the convergence of IP and wireless networks and the proliferation of QoS-demanding IP applications (such as VoIP). It is also emphasized that a global uniform end-to-end IP QoS solution is not realistic. Based on this remark, packet-level QoS mechanisms are classified as certain building blocks, each one fulfilling different objectives in certain parts of a heterogeneous IP network. This taxonomy, being in line with the ITU-T initiative toward a QoS architectural framework for IP networks, gives rise to a thorough presentation of QoS “building blocks,” as well as their associated mechanisms. This presentation is followed by an illustration of how the various building blocks are combined in the scope of modern IP networks. However, offering QoS in a large scale IP-based network demands that additional (i.e. non-packet-level) QoS mechanisms are deployed in some parts. Therefore, we also present prominent technologies and mechanisms devised to augment the QoS capabilities of access, wireless, and optical networks. We illustrate how these mechanisms boost end-to-end QoS solutions and reveal interworking issues with packet-level mechanisms.

Application-oriented network metrology: metrics and active measurement tools

Abstract: The science of communication network metrology consists of measuring the performance of networks. This article is a tutorial on application-oriented measurement tools and techniques for IP networks. First the principles of active measurements are introduced and two important active measurement initiatives are presented. Since metrology often requires precision in timing, a basic overview related to time in computers and networks will be presented, followed by a definition of principal network metrics. Metrics that will be discussed are one-way delay, delay variation, round-trip time, packet loss, packet reordering, route, and bandwidth. For each parameter, a definition is given and related measurement tools and techniques are presented. APPLICATION-ORIENTED NETWORK METROLOGY: METRICS AND ACTIVE MEASUREMENT TOOLS SECOND QUARTER 2005, VOLUME 7, NO. 2 www.comsoc.org/pubs/surveys 1 Previous works on telecommunication lines or circuit-switched networks focus on similar performance parameters (delay, jitter, etc.). However, conceptual and technical differences between these networks and packetswitched networks induce a new metrology approach. 1553-877X/05/$20.00 © 2005 IEEE IEEE Communications Surveys & Tutorials • Second Quarter 2005 3 Passive techniques are carried out by observing network traffic flows. They consist of capturing packet headers and analyzing them. The best example of a capture tool is tcpdump, which is based on the libpcap library [12]. These techniques do not add to network traffic. Passive measurement can be done on two levels: • At a microscopic level measurements are performed on each packet traveling across the measurement point. An example of collected information is packet size. • At a macroscopic level measurements are performed on flows. In this case, aggregation rules are necessary to match packets into flows. Examples of collected data are the number of flows per unit of time, flow bitrate, etc. The “Real-time Traffic Flow Measurement” (RTFM) working group of the Internet Engineering Task Force (IETF) has worked on macroscopic measurements. It has helped create a general passive measurement architecture and describe the manner in which aggregation rules are defined. Today this working group is closed. Passive measurement techniques are particularly suitable for (but not limited to) traffic engineering because they show flow dynamics and distribution. The main problem with passive measurement is the data volume. The volume of captured data can become very large on high-capacity links. Moreover, it is hard to obtain end-to-end measurements passively: the presence of traffic traveling between two measurement points cannot be ensured and matching measurements that are performed on different measurement points is difficult. Consequently, passive measurements are usually used to determine metrics characterizing one particular network element (“at-apoint” metrics). On the other hand, active measurements are performed by sending probe packets to the network. The measurement flow travels from source to destination. Upon reaching its destination, it is possible to calculate metrics by analyzing them. Active measurements can determine the end-to-end QoS experienced by a measurement flow for a particular path and then measure the QoS as it is seen by applications. Additionally, active measurements offer the flexibility to send probe packets streams with particular properties (bitrate, packet size, etc.). The main drawback of active measurements is that additional network traffic is introduced. This “intrusive” (or “invasive”) characteristic can potentially modify the properties that are trying to be measured. First, it can result in measurement errors or bias; second, it can lead to network overload. The measurement traffic thus has to be limited to avoid network disturbance and measurement errors. As previously mentioned, the major idea behind active measurements is to perform QoS monitoring and to verify SLA. However, since active measurements determine the endto-end QoS as seen by applications, this type of measurement is also useful for distributed applications (particularly when complete control of network resources is not possible). In this case, an understanding of the QoS of the network can allow applications to adapt their execution to resource fluctuations. For example, applications can adapt their throughput to the loss of the network or the size of play-out buffers to the network delay [13]. More complex application adaptation schemes have been proposed [14–19]. In this context, we will examine new developments of application-oriented metrology techniques and tools. Note that metrology for traffic engineering is beyond the scope of this article. The main objective of this article is thus to give a tutorial on application-oriented measurement tools and techniques. The first section presents active measurement generalities. It presents active measurement principles and limitations, and discusses the IETF working group dedicated to active measurement and the NIMI project. Since active measurements often need time and clock constraints to be achieved, the second section deals with timing considerations. Each of the next seven sections is devoted to the following network parameters: one-way delay, delay variation (also referred to as jitter), round-trip time, packet loss, packet reordering, route, and bandwidth measurement. Definitions, measurement techniques, and tools2 are presented for each parameter. Then we discuss the problem of “intrusiveness” that occurs with active measurements. Finally, we present our conclusions.

Multicast receiver and sender access control and its applicability to mobile IP environments: a survey

Abstract: Ensuring secure access control to multicast delivery trees is a challenging issue that is still largely open. Moreover, the impact of host mobility on the access control to the delivery tree has not been investigated. In this article we address the receiver and sender access control problems to the delivery tree and extend the interest to the mobile IP environment by taking into account its particular issues and requirements. To achieve this, we review the existing approaches by classifying them into three classes: digital signature-based solutions, shared secret-based solutions, and hybrid solutions. We also investigate their efficiency and limitations with respect to the specified requirements both in stationary and mobile cases. Our study shows that four main problems arise among the existing approaches. First, few approaches addressed the sender access control problem. Second, both the digital signature- based solutions and hybrid solutions are vulnerable to DoS attacks. Third, the existing solutions do not provide an efficient user exclusion mechanism. Fourth, the defined access control mechanisms result in a number of problems in mobile IP environments.

Charging and pricing challenges for 3G systems

Abstract: Mobile operators and service providers require a flexible charging system/mechanism that accommodates various pricing models, such as models based on a flat rate, call duration, call volume, Quality of Service (QoS), or user perceived quality, in order to fulfill not only conventional business models but also innovative models. This article reviews current methods for pricing, charging, and billing for 3G mobile services. It further recommends that charging and billing methods be reexamined, as charging by simple metrics for wireless network and service providers will result in lost revenue. This article examines the selection of a specific pricing method, which could be based on customer and service profile characteristics. It discusses the characteristics that are exhibited in third generation (3G) type services but are non-existent in the previous services, leading to new and challenging methods to account for their usage. This article also reports that innovative approaches are needed when considering the application of accounting principles such as mediation, billing, and charging to these new services.

Handoff prioritization schemes using early blocking

Abstract: Upcoming cellular networks are based on the Internet Protocol (IP) to provide efficient support for applications with bursty traffic characteristics, for example, WWW browsers. Such IP-based networks must include Quality of Service (QoS) mechanisms to enable the use of real-time applications such as mobile telephony. A major problem with regard to QoS is that such real-time applications have to be interrupted after a handoff if the new cell cannot provide sufficient resources. A large number of different schemes have been proposed to deal with this problem. Basically, they give priorities to sessions performing a handoff into a cell compared to newly arriving sessions in that cell. In this manner, such handoff prioritization schemes can avoid or reduce communication interruptions after a handoff. This article introduces the basic functions of handoff prioritization schemes and describes one proposal for a classification of these schemes. Based on this classification, it finally presents a survey of available schemes.

Service naming in large-scale and multi-domain networks

Abstract: The increasing availability of high-performance network resources creates a rich breeding ground for widely-distributed applications that span multiple network domains or administrative domains. Such applications provide services that can be accessed by remote users. Discovery and management of these systems require the ability to name the provided services. In light of these requirements, we distill a set of criteria for comparison of naming schemes: readability, extensibility, namespace size, naming authority, name resolution architecture, name persistence, and standardization. Based on these criteria, we summarize and compare a representative set of existing naming and name resolution approaches. We analyze the approaches based on our criteria, and select a number of candidate technologies for the design of a naming and name resolution mechanism suitable to a multi-domain, Internet-scale environment.