Panos Trimintzios

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.

A policy-based quality of service management system for IP DiffServ networks

Policy-based management can guide the behavior of a network or distributed system through high-level declarative directives that are dynamically introduced, checked for consistency, refined, and evaluated, resulting typically in a series of low-level actions. We actually view policies as a means of extending the functionality of management systems dynamically, in conjunction with preexisting hard-wired management logic. We first discuss the policy management aspects of architecture for managing quality of service in IP DiffServ networks as presented by Trimintzios et al. (see IEEE Commun. Mag., Special Issue in IP Operations and Management, vol.39, no.5, p.80-88, 2001), and focus on the functionality of the dimensioning and resource management aspects. We then present an analysis of the policies that can influence the dimensioning behavior as well as the inconsistencies that may be caused by the introduction of such policies. Finally, we describe the design and implementation of the generic policy consumer component and present the current implementation status.

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.

Quality of Future Internet Services

This book is the final report of COST – Cooperation europeenne dans le domaine de la recherche scientifique et technique , Action 263 – Quality of future Internet Services.

Scalable monitoring support for resource management and service assurance

Continuous monitoring of network status and its resources are necessary to ensure proper network operation. Deployment of QoS-based value-added services in IP networks necessitates the employment of resource management techniques and specifically the use of traffic engineering. The latter typically relies on monitoring data for both offline proactive and dynamic reactive solutions. The variety of data to be collected and analyzed using different measurement methods and tools, and the extent of monitoring information to use demand a proper QoS monitoring infrastructure. A monitoring system should be scalable in terms of network size, speed, and number of customers subscribed to value-added services. This article investigates the requirements of scalable monitoring system architectures, proposes principles for designing such systems, and validates them through the design and implementation of a scalable monitoring system for QoS delivery in IP differentiated services networks. Experimental assessment results prove the accuracy and scalability of the proposed monitoring system.

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.

DiMAPI: An Application Programming Interface for Distributed Network Monitoring

Network monitoring and measurement is commonly regarded as an essential function for understanding, managing and improving the performance and security of network infrastructures. Traditional passive network monitoring approaches are not adequate for fine-grained performance measurements nor for security applications. In addition, many applications would benefit from monitoring data gathered at multiple vantage points within a network infrastructure. This paper presents the design and implementation of DiMAPI, an application programming interface for distributed passive network monitoring. DiMAPI extends the notion of the network flow with the scope attribute, which enables flow creation and manipulation over a set of local and remote monitoring sensors. Experiments with a number of applications on top of DiMAPI show that it has reasonable performance, while the response latency is very close to the actual round trip time between the monitoring application and the monitoring sensors. A broad range of monitoring applications can benefit from DiMAPI to efficiently perform advanced monitoring tasks over a potentially large number of passive monitoring sensors

A scalable real-time monitoring system for supporting traffic engineering

Quality of service based value-added services in IP networks necessitate the use of traffic engineering. The latter relies typically on monitoring data for both offline, proactive and dynamic, reactive solutions. A monitoring system should be scalable in terms of network size, speed and number of customers subscribed to value-added services. The article investigates the requirements of scalable monitoring system architectures, proposes principles for designing such systems and validates them through the design and implementation of a scalable monitoring system for QoS delivery in IP differentiated services (DiffServ) networks. Experimental assessment results are also presented.

Heterogeneous real-time traffic admission control in differentiated services domains

In differentiated services (DiffServ) domains, where services are provisioned on a per-class basis, admission control is an essential control factor in order to ensure that congestion is avoided and that the quality of service (QoS) requirements of individual flows are met. We consider traffic-engineered and provisioned IP differentiated services domains able to support real-time traffic. We present a new measurement-based admission control (MBAC) scheme that uses measurements of aggregate bandwidth only, without keeping the state of any per-flow information. In our scheme there is no assumption made on the nature of the traffic characteristics of the real-time sources, which can be of any heterogeneous nature. Through simulations we show that the admission control scheme is robust with respect to traffic heterogeneity and measurement errors. We also show that our approach compares favorably against other admission control schemes found in the literature.

On Policy-Based Extensible Hierarchical Network Management in QoS-Enabled IP Networks

Policy-based Management has been the subject of extensive research over the last decade. More recently, the IETF has been investigating Policy-based Networking as a means for managing IP-based multi-service networks with quality of service guarantees. Policies are seen as a way to guide the behaviour of a network or distributed system through high-level, declarative directives. We mainly view policies as a means of extending the logic of a management system at runtime, so that it can be adaptive to changing or newly emerging requirements. We are interested in particular in the coexistence of hard-wired hierarchical management systems with policy logic in a fashion that the overall system becomes programmable and extensible. In this paper we consider generic issues behind hierarchical policy-based management systems and we present initial work on such a system for dimensioning and dynamic resource management in IP Differentiated Services networks.