Panos Georgatsos

A management and control architecture for providing IP differentiated services in MPLS-based networks

As the Internet evolves toward the global multiservice network of the future, a key consideration is support for services with guaranteed quality of service. The proposed differentiated services framework is seen as the key technology to achieve this. DiffServ currently concentrates on control/data plane mechanisms to support QoS, but also recognizes the need for management plane aspects through the bandwidth broker. In this article we propose a model and architectural framework for supporting DiffServ-based end-to-end QoS in the Internet, assuming underlying MPLS-based explicit routed paths. The proposed integrated management and control architecture will allow providers to offer both quantitative and qualitative services while optimizing the use of underlying network resources.

Admission control for providing QoS in DiffServ IP networks: the TEQUILA approach

Admission control is a key component for QoS delivery in IP networks because it determines the extent to which network resources are utilized and whether the contracted QoS characteristics are actually delivered. Unlike most of the existing approaches, we adopt a holistic view and position the admission control in a unified architecture, where traffic engineering and service management interact in different levels of abstraction and timescale. Distinguishing between service subscription and invocation epochs, the applied admission logic is based on a feedback model, the operation of which can be tuned by operational policies and business strategies. The validity of the approach is supported by a scalability analysis while it has also been verified by a prototype system.

Provisioning for interdomain quality of service: the MESCAL approach

This article presents an architecture for supporting interdomain QoS across the multi-provider global Internet. While most research to date has focused on supporting QoS within a single administrative domain, mature solutions are not yet available for the provision of QoS across multiple domains administered by different organizations. The architecture described in this article encompasses the full set of functions required in the management (service and resource), control and data planes for the provision of end-to-end QoS-based IP connectivity services. We use the concept of QoS classes and show how these can be cascaded using service level specifications (SLSs) agreed between BGP peer domains to construct a defined end-to-end QoS. We illustrate the architecture by describing a typical operational scenario.

End-to-end quality of service provisioning through inter-provider traffic engineering

This paper addresses the issue of delivering solutions that will enable the incremental implementation of inter-domain quality of service (QoS) in the multi-provider commercial Internet. The paper first introduces a holistic architecture that describes the key functions required to support inter-domain QoS, and then proceeds to present results from two major components of the architecture. A genetic algorithm for QoS-aware offline inter-domain traffic engineering is first presented, and it is shown through simulation studies how this can optimise the apportionment of QoS provisioning between adjacent domains. Secondly, QoS enhancements to BGP are proposed and the results of a testbed implementation are described, demonstrating how this QoS-enhanced BGP can deliver inter-domain QoS routing.

Interdomain routing through QoS-class planes [Quality-of-Service-Based Routing Algorithms for Heterogeneous Networks]

This article presents an approach to delivering qualitative end-to-end quality of service (QoS) guarantees across the multiprovider Internet. We propose that bilateral agreements between a number of autonomous systems (ASs) result in the establishment of QoS-class planes that potentially extend across the global Internet. The deployment of a QoS-enhanced border gateway protocol (BGP) with different QoS-based route selection policies in each of the planes allows a range of interdomain QoS capabilities to coexist on the same network infrastructure. The article presents simulation results showing the benefits of the approach and discusses aspects of the performance of QoS-enhanced BGP

A Framework for End-to-End Service Differentiation: Network Planes and Parallel Internets

This article presents a technology-agnostic and a multi-dimensional (i.e., routing, forwarding, and traffic management dimensions) approach for the management of IP network resources to ensure service differentiation with both intra- and inter-domain scope. This article introduces the network plane (NP) and parallel Internets (PI) concepts for achieving service differentiation. Based on these concepts, a functional architecture together with a business model is presented. In addition, this article describes how the proposed approach can become a promising platform for the IP multimedia subsystem (IMS), with the objective of providing end-to-end QoS-enabled multimedia delivery across multiple providers to replace the flow-based reservation mode known as the VoIP resource reservation framework.

An architectural framework for providing QoS in IP differentiated services networks

As the Internet evolves, a key consideration is support for services with guaranteed quality of service (QoS). The proposed differentiated services (DiffServ) framework, which supports aggregate traffic classes, is seen as the key technology to achieve this. DiffServ currently concentrates on control/data plane mechanisms to support QoS but also recognises the need for management plane aspects through the bandwidth broker (BB). In this paper we propose a model and architectural framework for supporting end-to-end QoS in the Internet through a combination of both management and control/data plane aspects. Within the network we consider control mechanisms for traffic engineering (TE) based both on explicitly routed paths and on pure node-by-node layer 3 routing. Management aspects include customer interfacing for service level specification (SLS) negotiation, network dimensioning, traffic forecasting and dynamic resource and routing management. All these are policy-driven in order to allow for the specification of high-level management directives. Many of the functional blocks of our architectural model are also features of BBs, the main difference being that a BB is seen as driven purely by customer requests whereas, in our approach, TE functions are continually aiming at optimising the network configuration and its performance. As such, we substantiate the notion of the BB and propose an integrated management and control architecture that will allow providers to offer both qualitative and quantitative QoS-based services while optimising the use of underlying network resources.

A management system for load balancing through adaptive routing in multi-service ATM networks

This paper proposes a hierarchical approach to the routing issue in ATM-based broadband multi-service networks. We show how distributed route selection algorithms embedded within network nodes may be managed by a TMN system, by virtue of a management service called load balancing, to increase their adaptivity to network wide conditions and therefore their effectiveness. The paper elaborates on the issues involved, presents specific algorithms and a TMN-compliant management architecture. The proposed management service influences the routing decisions by conveying network-wide information and contributes to the network load balancing by directing the routing algorithms to route traffic to the least congested network areas. Results regarding the effect of the proposed management system on the network operation are also presented.

A TMN system for VPC and routing management in ATM networks

In this paper we present a VPC and Routing Management Service for multi-class ATM networks. Considering the requirements, we decompose the Management Service into a number of distinct but cooperating functional components which we map to the TMN architecture. We describe the architectural components and analyse their operational dependencies and information exchange in the context of the overall system operation.

Provider-level service agreements for inter-domain QoS delivery

In the current Internet, business relationships and agreements between peered ISPs do not usually make specific guarantees on reachability, availability or network performance. However, in the next generation Internet, where a range of Quality of Service (QoS) guarantees are envisaged, new techniques are required to propagate QoS-based agreements among the set of providers involved in the chain of inter-domain service delivery. In this paper we examine how current agreements between ISPs should be enhanced to propagate QoS information between domains, and, in the absence of any form of central control, how these agreements may be used together to guarantee end-to-end QoS levels across all involved domains of control/ownership. Armed with this capability, individual ISPs may build concrete relationships with their peers where responsibilities may be formally agreed in terms of topological scope, timescale, service levels and capacities. We introduce a new concept of QoS-proxy peering agreements and propose a cascade of inter-domain Service Level Specifications (SLSs) between directly attached peers: each ISP meeting the terms of the SLSs agreed with upstream peers by being responsible for its own intra-domain service levels while relying on downstream peers to fulfill their SLSs.