The service requests of intra-datacenter networks (intra-DCNs) are different from the traffic demands of traditional transport networks in the following features. First, the latter is typically generated between dedicated node pairs that only require sufficient transmission bandwidth. Intra-DCN service requests, in contrast, require IT resources, such as computational, memory and storage resources, in addition to the transmission bandwidth. Second, for a given intra-DCN service request, any intra-DCN node that can provide the required IT resources can serve as a destination node (i.e., anycast). Thus, this type of network poses an important research problem of routing and spectrum/IT resource assignment (RSIA). To support these features, we first develop an integer linear programming (ILP) model to address the static RSIA problem, and then to propose efficient heuristic algorithms to address the dynamic RSIA issues, subject to the intra-DCNs' limited network resources. The results of the proposed ILP model and heuristic algorithms are compared with the traditional network models and algorithms. It is found that the proposed ILP model and heuristic algorithms perform much better than the traditional approaches in terms of using intra-DCN network resources and reducing the service-request blocking probability.