Dynamic SLA-based QoS Control for Third Generation Wireless Networks: The CADENUS Extension Rajiv Chakravorty, Ian Pratt and Jon Crowcroft Maurizio D’Arienzo {FirstName.LastName}@cl.cam.ac.uk maudarie@unina.it University of Cambridge, Cambridge CB3 0FD, U.K. University of Naples, Italy Abstract— With the evolution of QoS-capable third generation wireless networks, the wireless community has been increasingly looking for a framework that can pro- vide an effective, network independent, end-to-end QoS control. In this paper, 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 ef- fective wired-wireless QoS translation, an efficient QoS control and management, and a dynamic SLA policy-based QoS provisioning. Keywords—QoS control, UMTS, SLA, Policy, CADENUS I. I NTRODUCTION The current Internet is best-effort that lacks any Quality of Service (QoS) support mechanism. This has lead the Internet Engineering Task Force (IETF) to seek for an appropriate QoS management solution, the outcome of which has resulted in two distinct Internet QoS paradigms – IntServ and DiffServ. Both paradigms typically attempt to address, in their own way, QoS management in the Internet. Meanwhile, the in- troduction of Universal Mobile Telecommunications System (UMTS) standard for third generation wireless networks is being widely looked upon as the Internet’s future wireless extension. With Internet’s ever expanding dimensions, constituting heterogeneous wired and wireless networks, the focus is gradually shifting towards a model for achieving an end-to-end QoS control rather than looking for simple QoS control for a specific network. Take for instance European Telecommunications Standard Institute (ETSI) UMTS Release 99 [4], where work based on similar lines to that of IETF – with a penchant to an “all-IP” architec- ture – targets on achieving an end-to-end QoS control rather than plain wireless QoS. However, despite all the efforts made in this direction, the goal to realize an effective end-to-end QoS control scheme in a wired-wireless environment still remains to be seen. There are some fundamental chal- lenges that has to be overcome in order to achieve this goal: • Network Level QoS Translation (Mapping) :– Service differentia- tion 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) mech- anism, • Dynamic QoS Management :– This includes dynamic QoS moni- toring and control. Proper monitoring of the network as per the user agreements, and control that can statically or even dynamically arbi- trate or modify the QoS available from the network, • Control Management Infrastructure :– Networks will have to en- sure QoS control in their own way using their own sets of control mech- anisms. These mechanisms will enable establishment, maintenance and termination of underlying network QoS. To achieve an interoperability strategy between these control mechanisms, in the quest for an end-to- end QoS control, would necessitate a framework that takes care of both – wired as well as wireless QoS. In this paper, we address the aforementioned issues with a simple extension to the CADENUS (IST CADENUS Project, http://www.cadenus.org) framework (see, [1], [2]) that takes care of the end-to-end QoS control. The CADENUS framework defines an integrated architecture for creation, configuration and provisioning of end-user services for the networks that offer some sort of service differ- entiation (premium IP networks). It defines a logical architecture that is functionally partitioned into number of components (which we dis- cuss later) for realization of such a framework. Our approach considers an extension to the existing CADENUS framework, and derives all the benefits of this framework to achieve a simple, yet effective, end-to-end QoS control for wired-wireless (UMTS) environment. An important first step in this direction is to judiciously interwork QoS’s of both wired as well as wireless (UMTS) network. ETSI specif- ically envisages different ways of interworking UMTS QoS with In- ternet QoS. The Third Generation Partnership project (3GPP) currently specify [4] 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 and, (4) us- ing service level aggreements (SLAs) enforced by the network border routers. This paper will, however, limit the discussion to achieving such an end-to-end QoS control using a combined mix of dynamic SLA- based and policy control schemes. The paper is structured as follows: Section II sets the context by re- viewing QoS related issues pertaining to UMTS. Section III delineates the CADENUS framework and Section IV describes the proposed CA- DENUS extension for UMTS. Section V elaborates on the experimental test platform, while Section VI discuss related work. The last section concludes the paper. II. UMTS QUALITY OF SERVICE I SSUES A. UMTS Architecture UMTS defines a system architecture that consists of a number of logi- cal network elements, with each element having a defined functionality. Three main functional network elements are defined [3]: UMTS Ter- restrial Radio Access Network (UTRAN) that handles all radio-related functionality, the circuit-switched (CS) and packet-switched (PS) do- main along with the two fundamental support nodes - the serving GPRS support node (SGSN) and gateway GPRS support node (GGSN), and fi- nally the core network (CN) in UMTS that has been adopted from the General Packet Radio Service (GPRS) architecture. MSC/VLR RNS SGSN HLR GGSN GGSN UE PDN (Internet) Other PLMNs Signaling Interface Signaling and Data Interface SGSN Uu Iu(CS) Gn Gr D Gc Gp Gi Gn Iu(PS) Gs UE: User Equipment RNS: Radio Network Subsystem VLR/HLR: Visitor/Home Location Register MSC: Mobile Switching Center PDN: Packet Data Network SGSN: Serving GPRS Support Node GGSN: Gateway GPRS Support Node PLMN: Public Land Mobile Network Core Network (CN) Fig. 1. UMTS Architecture The core network in the PS domain connects UTRANs with the ex- ternal networks through the GSNs. User equipment (UE) that inter- faces the user and the radio-interface is also defined, which consists of 938 0-7803-7802-4/03/$17.00 © 2003 IEEE