Eugenia G. Nikolouzou

QoS issues in the converged 3G wireless and wired networks

The Internet evolution delineated through the last years has urged the wireless network community to support the deployment of IP multimedia services with guaranteed quality of service (QoS) in 3G wireless networks. This article copes with the interoperability between 3G wireless networks and wired next-generation IP networks, for the provision of services with an a priori known quality level over both environments. More specifically, the UMTS architecture as well as a prototypical implementation of the next-generation Internet based on DiffServ are considered. The article focuses on the mapping among the traffic classes of the two networks at the point where the networks converge, and discusses the requirements and possible solutions for their proper interworking at the signaling and user levels. Simulations prove that proper mapping among the traffic classes of each world is necessary in order to achieve the desired end-to-end traffic characteristics.

End-to-end QoS specification issues in the converged all-IP wired and wireless environment

The emerging next-generation networking environment presents an IP-based core interconnecting many wireless radio access networks, providing ubiquitous access to end users through a vast variety of wireless devices. Although the IP protocol is the common denominator, the new environment brings together many different interconnecting domains, each following different QoS models, complicating the overall end-to-end QoS process. This article discusses the need to standardize an end-to-end QoS protocol. It does not, however, focus on the signaling mechanism, since there is currently a relevant ongoing activity in IETF. Instead, it concentrates on the formulation of the QoS information describing the QoS requirements of the session to be established. It presents the generic service specification framework that not only enables the QoS requirements of a specific session to be captured (like a generic QoS template), but also the QoS classes of each IP domain can be described according to it. Through the systematic specification of a domains QoS classes, an intelligent automatic mapping algorithm can be applied during an end-to-end QoS request, in order to select the most appropriate service class in each domain, as well as to extract the required traffic-related parameters to perform traffic control operations, such as admission control, policing, and scheduling.

An adaptive algorithm for resource management in a differentiated services network

The Internet is widely known for lacking any kind of mechanism for the provisioning of quality of service guarantees. An overlay resource control management layer on top of a differentiated services core network is introduced for managing and adjusting the resources among network elements. This layer realises an algorithm which provides a dynamic approach for resource distribution. Our experimental results show that this algorithm can allocate network resources according to the traffic load and provide an adaptive and efficient way for re-distributing the resources among network elements.

QMTool: an XML-based management platform for QoS-aware IP networks

Technological and human factors have contributed to the increasing complexity of the network management problem. Heterogeneity and globalization of network resources have, on one hand, increased user expectations for flexible and easy-to-use environments and, on the other, propounded entirely novel ways to face the management problem. Several research efforts recognize the need for integrated solutions to manage both network resources and services in open and global environments. Undoubtedly, these solutions should permit the coexistence of different management models and should interoperate with legacy systems. The presented management system, QoS management tool (QMTool), aspires to address the heterogeneity, complexity, and dynamic behavior of QoS-enabled IP networks by taking advantage of the optimum fit of a number of novel technologies. A layered framework architecture, including element, network management, and visualization service, is provided, and a high level of information abstraction in network configuration and monitoring is introduced mainly based on the capabilities of the Extensible Markup Language (XML). Moreover, the functional components for providing (re-)configuration, fault management monitoring, and network visualization facilities are also presented, followed by notes of implementation issues.

A study of QoS performance for real time applications over a differentiated services network

The differentiated service architecture (DiffServ) is currently a popular research topic as a low-cost method to provide quality of service to the different applications in the Internet. This paper addresses the definition and deployment of specific network services in a DiffServ environment. Each network service is appropriate for a specific type of traffic and is realized through its own network mechanisms, which are the traffic classes. The focus of the paper is the services appropriate for real time delay-sensitive applications such as voice and video. Different traffic control algorithms are studied for the implementation of the proposed services. Simulation results show that the proposed traffic control mechanisms provide hard performance guarantees to different flows.

Dynamic resource management for QoS provisioning over next-generation IP-based wireless networks

A significant issue in current research pursuits is the formulation of the requirements and basic design options for the next-generation wireless network architecture. The next-generation of wireless systems will support a diverse set of access technologies and mobile devices, formulating a broad heterogeneous environment with increased requirements on network support operations. It is expected that the demanding breed of multimedia applications will even more considerably require Quality of Service support throughout the end-to-end path. This paper first provides a tutorial approach on next-generation wireless network architectures and more specifically on end-to-end QoS provision. We claim that dynamic resource management in the Core Network is a necessity due to the increased heterogeneity of the new environment. We subsequently present our proposal regarding a dynamic resource management scheme that is based on the concept of the Resource Pools. The Resource Pool concept is deeply analysed within the paper and simulation results prove its correctness and appropriateness.

Network services definition and deployment in a differentiated services architecture

Next generation Internet architectures will consider the differentiated services paradigm for the provision of quality of service to the individual customer needs and applications. This paper addresses the definition and deployment of specific network services in a DiffServ environment. The proposed network services and the underlying traffic engineering methods are analyzed and simulated. Simulation outcomes prove that the fundamental principles of the network services are fulfilled.

Resource management techniques for dynamic multimedia content adaptation in heterogeneous networks

Moving towards an explosion of wireless and wired technologies coupled with an evolution of wireless terminal devices and different types of services, there is a growing need to decouple the service provision from the platform support. This need is considerably significant if we consider the influx of multi-media streaming content, the number of devices with different requirements and capabilities, the different service platforms and the uncountable number of software programs needed to be downloaded in order to present and manipulate the desired content. The architecture described in this paper presents a model for nomadic multimedia environments aiming at providing an “on-the-fly” adaptation of the delivery system. Taking advantage of the innovative capabilities offered by the current reconfigurable devices (FPGAs), the intelligent agent-based service provision and the advanced simulation techniques, it allows a hardware-independent delivery of content, where the end-devices can be reconfigured to optimally represent the multimedia content. Specifically, this paper focuses on the Simulation Server module of the architecture, which provides a dynamic and efficient approach for the optimum adjustment of the communication profile and adoption of the reconfiguration strategy, according to the user/network combination and device capabilities.

Applying the BGRP Concept for a Scalable Inter-Domain Resource Provisioning in IP Networks

Providing end-to-end QoS guarantees to mission critical applications comprises a main challenge for the today’s Internet infrastructure. The Differentiated Services architecture (DiffServ) enhanced by the Bandwidth Broker (BB) approach is a first step towards resource management. In this context, the architecture proposed in this paper realises a distributed BB architecture, in order to provide a more efficient way for managing the resources of a single domain.

Evaluating Common Privacy Vulnerabilities in Internet Service Providers

Privacy in electronic communications receives increased attention in both research and industry forums, stemming from both the users’ needs and from legal and regulatory requirements in national or international context. Privacy in internet-based communications heavily relies on the level of security of the Internet Service Providers (ISPs), as well as on the security awareness of the end users. This paper discusses the role of the ISP in the privacy of the communications. Based on real security audits performed in national-wide ISPs, we illustrate privacy-specific threats and vulnerabilities that many providers fail to address when implementing their security policies. We subsequently provide and discuss specific security measures that the ISPs can implement, in order to fine-tune their security policies in the context of privacy protection.