## 2 Related Work  
Standards bodies such as 3 GPP, ETSI's TISPAN and IETF have defined a number of policy-based control architectures which can be found in [7, 8, 9] for example. TISPAN specified a Resource and Admission Control Subsystem (RACS) comprising of a Service-based Policy Decision Function (SPDF) and Access Resource Admission Control Function (A-RACF) [4,8]. Both SPDF and A-RACF interact with Policy Enforcement Points (PEPs) in the underlying transport network. Similarly, the policy framework in the 3 GPP technical specifications defines a Policy Decision Function (PDF) as part of its policy-based architecture [7]. The 3 GPP and TISPAN policy-based architectures share similarity with the IETF policy model which specified PEP and a (Policy Decision Point) PDP as part of its architecture [9]. Although the standards' policy frameworks define function blocks, interfaces and protocols to facilitate interoperability of the standards-compliant products from different vendors, no details are provided on how the various functionalities would be implemented. Our work aims to bridge this gap by not only leveraging similar policy-based approach to develop scalable solutions for QoS management and control of converged networks but also introduces important novel extensions such as context-awareness support in the design, and _fuzzy-rule-based_ functionality in our implemented prototype in order to provide value-added enhancements to the basic PBNM operations. With the continuous evolution of access technologies coupled with the need to address their interoperability and management requirements within converged architectures, PBNM systems are still actively being researched. PBNM systems have recently been studied in different contexts such as tactical networks [10], MPLS Networks [11], virtualization environments [12], Virtual Private Networks [13], IMS-enabled networks [2], _etc._ In [10], [PERSON] _et al._, present a policy-based QoS framework built on DiffServ and SNMP for the purpose of QoS control in _ad hoc_ military environments. Although the authors demonstrated the efficacy of their framework using off-the-shelf technologies like we have undertaken in this paper, the design and application of their framework differs significantly from our CNQF approach. Moreover, unlike [10] our framework incorporates PBNM enhancements such as context management functionality and fuzzy-rule-based resource control as will be shown later in the paper. Similar to [10], [PERSON] _et al._ in [14] and [PERSON] and [PERSON] in [15] have also presented policy based management frameworks for DiffServ enabled networks. The same approach is extended to IMS networks by the authors of [2]. Whilst the system in [14] is built using EJB (Enterprise Java Beans), the framework in [15] relies on XML technologies. However, their work also did not consider the enhancements to the basic PBNM functionalities discussed, implemented and evaluated in this paper. In [16], [PERSON] and [PERSON] investigate the use of fuzzy logic for network management systems. The article suggests that network management can benefit immensely from the use of fuzzy logic in various possible applications areas. They also present a fuzzy-based method for customized resource allocation decisions. In particular, a Fuzzy Bandwidth Broker (FBB) is proposed for distributed architecture management of Bandwidth Brokers in a DiffServ domain and also its performance optimization. Using a fuzzy rule base, various performance metrics are used to decide when to switch from centralized to distributed Bandwidth Broker architecture as well as the number and optimum placement of Bandwidth Broker entities. Different from [16], our work investigates the application of fuzzy logic to a different problem in network management _i.e.,_ dynamic resource allocation for enhanced admission control especially for tiered services within practical PBNM systems, rather than Bandwidth Broker placement or their optimum topology selection.