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.