A framework for dynamic SLA-based QoS control for UMTS

With the evolution of QoS-capable third generation (3G) wireless networks, the wireless community has been increasingly looking for a framework that can provide an effective, network independent, end-to-end Quality of Service (QoS) control. In this article, we first construct such a framework and then describe how dynamic SLA-based control can be used to achieve end-to-end QoS in a wired and wireless (UMTS) environment. The proposed framework, which is an extension to the IST CADENUS project, offers an effective wired-wireless QoS translation, an efficient QoS control and management, and a dynamic SLA policy-based QoS provisioning. INTRODUCTION The Universal Mobile Telecommunications System (UMTS) standard for third generation wireless networks is gradually evolving, and networks based on this standard are beginning to be deployed thoughout Europe. With Internet’s ever expanding dimensions, constituting heterogeneous wired and wireless networks, focus is shifting towards a model that can achieve end-to-end QoS control rather than QoS control models for specific networks. Take for instance European Telecommunications Standard Institute (ETSI) UMTS Release 99 [4], where work based on similar lines to that of the IETF – with a penchant towards an “all-IP” architecture – targets achieving end-to-end wired-wireless QoS control rather than plain wireless QoS. However, despite the efforts made in this direction, the goal to realize an effective end-to-end QoS control scheme in a wired-wireless environment is still unfulfilled. There are some important challenges that have to be overcome: Network Level QoS Translation (Mapping). Service differentiation based on a set of traffic classes, for both wireless as well as IP-core, needs an effective and reliable QoS translation (or QoS mapping) mechanism. Dynamic QoS Management. This includes dynamic QoS monitoring and control. Proper monitoring of the network as per the user agreements, and control that can dynamically arbitrate or modify the QoS available from the network. Control Management Infrastructure. Networks will have to ensure QoS control using their own sets of control mechanisms. These mechanisms will enable establishment, maintenance and termination of underlying network QoS. To achieve interoperability between these control mechanisms, in the quest for end-to-end QoS control, would necessitate a framework that takes care of both – wired as well as wireless QoS. In this article, we address the aforementioned issues with a simple extension to the CADENUS framework [2] to achieve a simple, yet effective, end-to-end QoS control in a wired-wireless environment. The CADENUS framework currently only defines an integrated architecture for creation, configuration and provisioning of end-user services for wired networks that offer some kind of service differentiation (e.g., premium IP networks) [1]. A first step in this direction would be to interwork QoS’s of both wired as well as wireless (UMTS) network. ETSI specifies different ways of interworking UMTS QoS with Internet QoS. The Third Generation Partnership project (3GPP) [4] currently specify the use of: (1) signalling (e.g. RSVP, LDP) along the flow path, (2) packet marking or labelling (e.g. DiffServ, MPLS), (3) inter-working policy control with network resource mediators or, (4) using service level aggreements (SLAs) enforced by the network border routers. In this article, we will discuss how we can achieve an end-to-end QoS control using a combined mix of dynamic SLA-based and policy control schemes. The article is structured as follows: we first set the context by reviewing QoS related issues pertaining to UMTS. We then delineate the CADENUS framework and describe the proposed CADENUS extension for UMTS. We discuss our initial evaluation through simulations, and our ongoing research over a real experimental testbed. UMTS QUALITY OF SERVICE ISSUES