Admission control for services

An admission control system is disclosed in combination with a network and a computing system in communication with the network. The computing system is configured to determine a class of service requirement from a service request. The computing system is furnished with topology information about the network, a portion of the topology being based on a protocol (e.g., Multiple Spanning Tree protocol) whereby multiple paths are created for provisioning a connection for the service request. A mechanism is configured to determine if at least one path is available that satisfies the class of service requirement and to admit the service request into the network when the path is available for provisioning the connection. Bandwidth usage may be tracked and used in provisioning decisions. Requests may be made to the network to add bandwidth (e.g., through additional optical wavelengths) to accommodate service requests.