Athanassios Liakopoulos

Standardizing a reference model and autonomic network architectures for the self-managing future internet

Research efforts at network design in the area of Autonomic Networking and Self-Managing Networks have reached a maturity level that forms a strong foundation toward standardization of architectural principles of the Self-Managing Future Internet. Therefore, an Industry Specification Group (ISG) on Autonomic network engineering for the self-managing Future Internet (AFI) has been established under the auspices of the European Telecommunications Standards Institute (ETSI). Upon its creation, the main stakeholders agreed to harmonize the previous developments and the most recent trends in the very vital field of autonomic and self-managing networks. Particularly, the life cycle of AFI is structured by Work Items providing the foundation for ETSI Group Specifications. So far AFI has been focusing on scenarios, use cases, and requirements for the autonomic/selfmanaging Future Internet, as well as on architectural reference model for autonomic networking and self-management. Most recently, AFI has continued with a new Work Item on requirements analysis and specification of implementation-oriented solutions for autonomics and self-management. At the same time, as a part of the global ecosystem, AFI is establishing strategic liaisons with the standards developing organizations and research community.

IP QoS across multiple management domains: practical experiences from pan-European experiments

GEANT is the pan-European 10 Gbs network interconnecting European national research and educational networks (NRENs). A Premium IP service based on the DiffServ EF PHB has been specified and implemented for this environment to provide quality of service to selected user groups on a Europe-wide scale. Basic features of Premium IP are described, and results from early experiments in the production networks of GEANT and the NRENs are presented. Next steps are proposed for achieving a fast and wide availability of Premium IP in the European research networks.

A study on network performance metrics and their composition

Purpose – Research backbone networks like GEANT2 and the national research and education networks are used by a variety of scientists and research projects. These users and the network engineers operating the networks would like to get access to network performance metrics to optimise their use of the network and to troubleshoot performance degradations when they happen. A variety of tools for performing network measurements already exist, and the perfSONAR architecture developed in the Joint Research Activity 1 (JRA1) of GEANT2 aims at integrating them into a coherent framework. However, a harmonised definition of the most interesting metrics and how measurements must be carried out is still lacking.Design/methodology/approach – This paper suggests some of the elementary metrics which are relevant for assessing network performance, along with an indication about how to post‐process (or “transform”, or “compose”) them in order to obtain derived summary values that can quickly and intuitively give an indic...

Providing rate guarantees for internet application traffic across ATM networks

The TCP/IP protocol suite is the standard requirement for all applications that need to communicate over the Internet. As TCP/IP applications are unable to specify the QoS parameters needed for most asynchronous transfer mode (ATM) services, they tend to use the unspecified bit rate (UBR) service category when running across ATM networks. The UBR service utilizes any bandwidth that is left unused by the rest of the ATM services. This has led the ATM forums traffic management group to define a new service category called guaranteed frame rate (GFR). GFR is intended to provide minimum cell rate guarantees and fair access to excess bandwidth left over from higher-priority services. This article first presents a tutorial overview of GFR and then presents a survey of the research work that has been carried out toward the design and implementation of associated ATM switch mechanisms.

Providing and verifying advanced IP services in hierarchical DiffServ networks-the case of GEANT

The differentiated services (DiffServ) framework is widely proposed as an efficient method for providing advanced IP services to large-scale networks, with QoS requirements. However, the provisioning of such services in production networks has proved to be more difficult than initially expected, in defining, setting and verifying appropriate Service Level Agreements (SLAs). GEANT, the Gigabit core pan-European research network, on a pilot basis introduced ‘Premium IP’ service, offering bounded delay and negligible packet loss to the European National Research & Education Networks (NRENs) that it interconnects. However, large scale provisioning of this new service requires the definition of efficient interaction procedures between administrative domains involved and methods for SLA monitoring. This paper focuses on these issues and presents the experience acquired from the early experiments in GEANT, as an example of hierarchical Gigabit multi-domain environment, enabled with QoS provisioning to its constituent NRENs. This model scales more efficiently than the common peering Internet Service provider (ISP) commercial paradigm. Finally, we outline other options that promise QoS, such as Layer 2 VPNs in MPLS backbones, with non-standard (yet) mechanisms. Copyright

NEURON: Enabling Autonomicity in Wireless Sensor Networks

Future Wireless Sensor Networks (WSNs) will be ubiquitous, large-scale networks interconnected with the existing IP infrastructure. Autonomic functionalities have to be designed in order to reduce the complexity of their operation and management, and support the dissemination of knowledge within a WSN. In this paper a novel protocol for energy efficient deployment, clustering and routing in WSNs is proposed that focuses on the incorporation of autonomic functionalities in the existing approaches. The design of the protocol facilitates the design of innovative applications and services that are based on overlay topologies created through cooperation among the sensor nodes.

QoS experiences in native IPv6 networks

Deployment of IPv6 technology in research and commercial networks has accelerated in the last few years. Inevitably, as more advanced services take advantage of the new technology, IPv6 traffic gradually increases. Today, there is limited experience in the deployment of Quality of Service (QoS) for IPv6 traffic in backbone networks that support the Differentiated Services framework. As available software and hardware are designed to handle IPv4 packets, there is a need to accurately measure and validate performance of QoS mechanisms in an IPv6 environment. This paper discusses tests and technical challenges in the deployment of IPv6 QoS in core networks, namely the production dual stack gigabit-speed Greek Research and Education Network (GRNET) and the IPv6-only 6NET European test network, using both hardware and software platforms. In either case, we succeeded in delivering advanced transport services to IPv6 traffic and provided different performance guarantees to portions of traffic. The deployed QoS schema was common to IPv6 and IPv4; in most cases both v4 and v6 traffic exhibited comparable performance per class, while imposing no significantly different overhead on network elements. A major conclusion of our tests is that the IPv6 QoS mechanisms are efficiently supported with state-of-the-art router cards at gigabit speeds.

Applying distributed monitoring techniques in autonomic networks

The increasing size, complexity and the dynamic character of future networks make traditional monitoring systems inadequate to be continuously updated and sense the endless changes in the topology and communication conditions. The need for reduction in the network management complexity and the administrators operational burden imposes the design and implementation of self-functionalities and the adoption of self-management schemes. We propose a novel approach for improving network management based on distributed monitoring techniques. Autonomic mechanisms are designed to control traffic monitoring within a network in order to increase the accuracy of the acquired data without increasing the imposed overhead in the network. Nodes are able to correlate monitoring data and to adapt the monitoring functions according to existing networking conditions and predefined administration policies.

Monitoring within an autonomic network: a GANA based network monitoring framework

The concept of self-managing of autonomic networks is a paradigm shift from todays management models, aiming at enabling networked nodes to self manage their behaviour within the constrains of the operators policies and objectives. In this article, we present our approach for self-coordinating monitoring functions within such an autonomic network. This approach complies with the principles of a recently introduced Reference Model for autonomic network engineering/self-management within node and network architectures dubbed: the Generic Autonomic Network Architecture (GANA), which aims to identify autonomic behaviours realised via hierarchical control loops among self-managing elements. The components of the proposed monitoring framework, the interactions among the identified elements and a complete use case scenario are described in detail.

Point-to-Point Services in Hybrid Networks: Technologies and Performance Metrics

Research networks, apart from pure IP packet-switched services, progressively introduce hybrid services, which combine packet switching and circuit switching technologies. Optical wavelengths (lambdas), SONET/SDH, 1/10 gigabit Ethernet are examples of technologies stitched together in order to realize point-to-point (P2P) services that cross multiple domains. Network monitoring aims to detect anomalies, assess performance degradations and localize faults in a network. In this paper, we discuss the challenges of monitoring P2P hybrid services deployed in a multi-domain environment. We briefly discuss diverse methods of transporting Ethernet traffic over hybrid networks and present performance metrics related to various layer 1/2 technologies. We give an example of a hybrid service and discuss why it is challenging to identify service degradation problems in a multi-domain environment.