Current Internet architecture is based on the Best Effort (BE) model, where packets can be dropped indiscriminately in the event of congestion. This architecture attempts to deliver all traffic as soon as possible within the limits of its abilities, but without any guarantees about throughput, delay and packet loss etc. Though such a model works well for certain traditional applications such as FTP, E-mail and less QoS constrained applications, it can be intolerable for newly emerged real-time, multimedia applications such as Internet Telephony, Video-Conferencing and Video on-Demand. This paper is based on the on-going research activities being carried out by various researchers in the area of QoS and proposes a Policy Based Network (PBN) architecture for the Differentiated Services (Diff-serv) Network. Policy Based Networking received much attention recently as the devices within the networks can be implemented with greater control. Our proposed architecture is based on the functionalities defined within the existing IETF/DMTF Policy architecture, with an objective to achieve QoS through proper Resource management techniques.