Policy Based Network Management (PBNM) simplifies the administration and management of communication networks. However due to the wide variety of policy representation forms, interoperability between different entities of PBNM systems becomes a concern. The Common Open Policy Service (COPS), which was standardized for policy control between a Policy Decision Function (PDF) and Policy Enforcement Point (PEP) had considerable shortfalls in efficiency and flexibility -its successor the Diameter protocol exhibits interoperability shortfalls. An XML-based policy provisioning solution presents great modeling capabilities that may overcome these shortfalls. The IP Multimedia Subsystem has adopted PBMN as the mechanism for resource and admission control. This paper reviews an XMLdriven architecture for policy control of DiffServ networks, and explores the incorporation of the proposed architecture into the IMS framework to perform policy control and enforcement. Proof of concept results of the XML-based policy control architecture are presented alongside design requirements for using it as an alternative to Diameter for IMS policy control.

A design, implementation, and evaluation of a Policy-based Management framework for DiffServ networks using XML technologies is presented. XML is used for policy representation throughout the entire policy life cycle, as well as in the communication protocol, reducing development costs, while promoting clarity, simplicity, and interoperability. Furthermore, performance evaluation results show that the proposed scheme generates less network traffic than its COPS-PR counterpart when protocol messages are compressed. Moreover, XML messages generate higher processing delays. The added processing overhead caused by compression to XML messages is very small, thus the gains in reduced network traffic generated outweigh the losses in terms of processing delays.