Afrodite Sevasti

SLA-based QoS pricing in DiffServ networks

The availability of high-speed transmission media and networking equipment in contemporary networks, as well as the evolution of quality-demanding applications has focused research interest on the provision of advanced qualitative services in addition to the traditional best-effort model of the Internet. A number of alternatives for service differentiation and QoS provisioning have been proposed and standardized, but in the case of backbone, transport networks the DiffServ architecture has prevailed, due to its scalability and deployment feasibility. The provisioning of services according to the DiffServ framework has in turn raised the requirements for interdependent, controlled resource allocation and service pricing, with particular needs for pricing mechanisms that preserve the potential and flexibility of DiffServ. At the same time, such mechanisms should reflect resource usage, allocate resources efficiently, reimburse costs or maximize service provision profits and lead customers to requesting services that will maximize their revenue. In this work, after reviewing related research, the principles that a pricing scheme for DiffServ-based services should follow are presented, stressing the differences form traditional Internet pricing. Based on these principles, an analytical approach to pricing a particular class of DiffServ-based services and a methodology for applying this approach in a real network are proposed and evaluated.

Service level agreements for DiffServ-based services' provisioning

The evolution of mechanisms for providing Quality-of-Service (QoS) over the contemporary network infrastructures has introduced the need for regulation and management of the emerging QoS services with the use of Service Level Agreements (SLAs). SLAs define the qualitative and quantitative characteristics of the services provided from a network provider to peering networks or customers. In this work, we define a template for the SLA structure to support the provision of a QoS service between two peering domains and then we proceed with the definition of an end-to-end SLA across consecutive domains, based on the bilateral ones. We also propose a model for the service provisioning procedures

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.

Enhancing the DiffServ architecture of a simulation environment

Simulation has always been a valuable tool for experimentation and validation of models, architectures and mechanisms in the field of networking. In the case of the DiffServ framework, simulation is even more valuable, due to the fact that an analytical approach of mechanisms and services is infeasible because of the aggregation and multiplexing of flows. In this work, we have extended the functionality of a widely used simulation environment towards the direction of realistic traffic generation and a series of mechanisms defined by the DiffServ architecture. The modules created are being presented and a case study of a simulation scenario that exploits the functionality provided by them is described.

QoS and SLA aspects across multiple management domains: the SEQUIN approach

The aim of this work is to define and implement an end-to-end approach to quality of service (QoS), operating across multiple management domains and exploiting a combination of link layer technologies. The architecture for the Premium IP service is presented, which aims at offering the equivalent of an end-to-end virtual leased line service at the IP layer across multiple domains. Also, the results of the initial testing performed for the validation of the service and the provisioning model for Premium IP are described. The work presented has been carried out in the framework of SEQUIN, a European Commission-funded research project.

Bandwidth on Demand Services for European Research and Education Networks

The Joint Research Activity 3 of the European project GN2 aims to specify and develop a prototype for a Bandwidth on Demand service destined to operate in a multi-domain environment using heterogeneous transmission technologies. This paper reviews the projects key achievements (general architecture and early prototyping results) and reports on current research and development areas (abstract network description, technology stitching and path finding) with a particular focus on inter-domain issues.

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

Analytical Approach and Verification of a DiffServ-Based Priority Service

The provision of Quality of Service (QoS) in a seamless way over the dominating internetworking protocol of our times (IP), has been a challenge for many researchers in the past years. Strict qualitative guarantees have proven difficult to provide in a way that has discouraged efforts in the area. The lack of a coherent provisioning methodology has been identified as the main reason for this. In this work, we are attempting an analytical yet straightforward approach to the provisioning methodology proposed for premium service of high-quality demanding traffic in the wide-area. Our approach is based on a series of well-known results of queuing theory but is proven to provide good approximations to experimental results as well as worthwhile qualitative guarantees.

A delay-based analytical provisioning model for a QoS-enabled service

Carefully designed and managed services are essential for quality-demanding traffic, especially in large-scale IP networks where the aggregation of flows and the variety of traffic types are extensive. Although individual mechanisms have been widely investigated, not much related work exists on integrated approaches to QoS provisioning that are also feasible to implement. This work presents a thorough approach to the design, dimensioning and provisioning of a high priority service for high-quality demanding traffic over an IP network. Our approach employs efficient scheduling and a dynamic admission control scheme while demonstrating novel characteristics in terms of the quality offered to IP flows.

Pricing QoS over transport networks

In recent years, a number of alternatives for service differentiation and QoS provision have been proposed and standardized in communication networks. In the case of back‐bone networks the DiffServ architecture has prevailed, due to its scalability and deployment feasibility. The provisioning of differentiated services has raised the requirements for interdependent controlled resource allocation and service pricing, with particular needs for pricing mechanisms that preserve the potential and flexibility of the DiffServ framework. At the same time, such mechanisms should reflect resource usage, allocate resources efficiently, reimburse costs or maximize service provision profits and lead customers to requesting services that will maximize their revenue. Presents the key issues involved in the area of pricing DiffServ‐based services and the research work carried out in this field, while at the same time outlining the basic principles that such a pricing infrastructure should obey with respect to the particularities that apply to the case of DiffServ services provision.