Network virtualization has been proposed as a diversifying attribute of the future inter-networking paradigm. By allowing multiple heterogeneous network architectures to cohabit on a shared physical substrate, network virtualization provides flexibility, promotes diversity, and promises increased manageability. One of the most fundamental issues in network virtualization is to support multiple virtual networks in the packet switches that constitute the underlying network infrastructures. A key challenge to supporting network virtualization in switches lies in resource allocation for meeting the performance requirements of different virtual networks. Buffered crossbar is becoming one of the dominating switch architectures widely deployed in network infrastructures. Therefore, how to support network virtualization in buffered crossbar switches becomes a significant research problem. The research study presented in this paper addresses the problem of resource allocation in buffered crossbar switches for supporting network virtualization. The main contributions of this paper include an analytical model for traffic control in buffered crossbar switches to support network virtualization and the analysis techniques for allocating resources, including processing capacity and buffer space, in the switch for supporting the performance requirements of various virtual networks. The modeling and analysis techniques developed in this paper are general and flexible; thus are applicable to support heterogeneous virtual networks in buffered crossbar switches with various packet scheduling schemes.