Techniques are described for managing communications for a managed virtual computer network overlaid on a distinct substrate computer network, including for communications between computing nodes of the managed virtual computer network connected to the substrate network and other network nodes external to the substrate network. To facilitate automation and tracking, each original communication to the client is tagged with a unique label, and replies to client responses are each correspondingly labeled. A group of interrupt requests is an MR priority of N sampled interrupt requests, M is the number of priority levels, and R is a resource sharing factor.