An Integrated System for QoS Monitoring of Policy-Based Networks Marcelo Borges Ribeiro, Lisandro Zambenedetti Granville Maria Janilce Bosquiroli Almeida, Liane Margarida Rockenbach Tarouco Federal University of Rio Grande do Sul - UFRGS Institute of Informatics Av. Bento Gonc ¸alves, 9500 - Bloco IV Porto Alegre, RS - Brazil {mribeiro, granville, janilce, liane}@inf.ufrgs.br Abstract. Policy-based management and QoS monitoring are both tasks related to the management of modern QoS-enabled network. Although related to each other, these tasks are currently executed in a non integrated fashion. This paper presents an architecture that integrates policy-based management and QoS monitoring through the extension of the original IETF policy-based management architecture. The main advantage of using our proposed approach is that network administrators are freed to execute other tasks, while the QoS-enabled network is still monitored. Another advantage is that we are monitoring policies and verifying if they are respected in the network even after its deployment, which is a new feature absent in the IETF solution. 1. Introduction The provisioning of QoS facilities in computer networks is intended to introduce levels of guaranties that are absent, for example, in the IP best-effort approach. Different QoS architectures have different accuracy for the provided services, which leads to a scenario where the expected QoS may not be always properly provided by the underlying architecture. In this context, QoS monitoring [Eder and Nag, 2001] is required to verify the observed QoS and compare it with the expected/contracted QoS. In a policy-based network, the expected QoS is defined by policies that orchestrate the network behavior. The Internet Engineering Task Force (IETF) has standardized several elements of a Policy-Based Network Management (PBNM) system [Moore et al., 2001], in which policies are defined using high-level languages, stored in policy repositories, deployed with the help of Policy Decision Points (PDPs) and enforced by Policy Enforcement Points (PEPs) [Westerinen et al., 2001]. In the IETF approach, once a policy is successfully deployed, the PBNM system no longer checks the policy behavior, and the QoS defined in the policy is assumed to be provided by the network. In fact, that is not always true. The underlying QoS provisioning architecture can be unstable or face problems, and the expected QoS may not be achieved. In order to verify QoS degradation in real management environments, today, the network administrator monitors the network and determines the provided QoS. Such QoS is then XXI Simpósio Brasileiro de Redes de Computadores 233