1. A method, comprising: selecting, at a central policy management device, a first set of resource admission control policies; receiving, at the central policy management device from a network service delivery device via a messaging network, a first request for delivering first data associated with a network service from the network service delivery device to a first customer device across a service delivery network, wherein the messaging network is different than the service delivery network; applying resource admission control, at the central policy management device, to selectively permit or deny delivery of the requested first data associated with the network service from the network service delivery device to the first customer device via the service delivery network based on the selected first set of resource admission control policies; sending a first admission control response, from the central policy management device to the network service delivery device, that indicates the selected permission or denial of the delivery of the first data associated with the network service to the first customer device; receiving, at the central policy management device via the messaging network, a notification related to a change in network topology or network capacity of the service delivery network; identifying, at the central policy management device, changes in the network topology or the network capacity of the service delivery network based on the notification; selecting, at the central policy management device, a second set of resource admission control policies based on the identified changes in the network topology or the network capacity of the service delivery network; receiving, at the central policy management device from the network service delivery device via the messaging network, a second request for delivering second data associated with the network service from the network service delivery device to a second customer device across the service delivery network; applying, at the central policy management device, the resource admission control to selectively permit or deny delivery of the requested second data associated with the network service from the network service delivery device to the second customer device via the service delivery network based on the selected second set of resource admission control policies; and sending a second admission control response, from the central policy management device to the network service delivery device, that indicates the selected permission or denial of the delivery of the second data associated with the network service to the second customer device.