Enabling end-to-end quality of service (QoS) for realtime video content delivery across heterogeneous P2P networks is challenging but vital for the efficient service provision. In this paper, we present a P2P based admission control mechanism for real-time video streaming driven by service provider (SP). SP- driven P2P network is a network where service provider has a comprehensive control over contracted resource utilization. SP assures the coordination and the creation of overlay P2P network and it is responsible for admission control and resource allocation among others. Our proposed QoS provision mechanism employs video traffic descriptor (i.e. traffic specification) for performing admission control. Before accepting a particular P2P video streaming session, the SP controls the access to the network resources by performing policy and admission control. After retrieving the service availability from its traffic repository, SP decides whether to accept or to reject the request. The proposed SP-driven P2P admission control mechanism is evaluated using ns2 simulator and the results show that our proposed mechanism allows the provisioning of end-to-end QoS for delivered video content over P2P network.