hierarchy between clusters the solution is based on a decentralized u201c flat u201d architecture split into telephony clusters tc the advantages of this solution are 1 this service partitioning in telephony clusters tc is scalable and 2 this service partitioning allows decreasing the overall complexity and the traffic of a large network according to the invention each service cluster is able to work in an autonomous manner from the others resilient further each service cluster is under the control of one and only one sapc authority it can be embedded in the calls control machine this approach does not exclude the usage of a distributed data base with a replication mechanism allowing each cluster to have the overall view of the network the term granularity is used to designate the smallest element of the network that has to be controlled by the admission mechanism the sapc an element is typically a link between nodes e g routers i e the satellite carrier this invention discloses to control both the real time service paths and the realtime services admission this admission control mechanism becomes a service admission path control sapc mechanism which has the knowledge of the cluster topology and by extension of the overall network topology and thus the knowledge of the real path between the communicating endpoints the network topology knowledge of the sapc mechanisms is maintained aligned consistent with the physical topology the physical topology taken into account by the sapc mechanism can be made of point to point physical links point to multipoint physical links multipoint to point and or multipoint to multipoint physical links the sapc of a cluster can be extended to another cluster in a redundancy purpose fig2 shows an example of a telephony cluster.