Admission Control based on Packet Marking and Feedback Signalling – Mechanisms, Implementation and Experiments

The abstract system design and a prototype implementation of an admission control system is described. The system exploits the load signal generated by low complexity active queue management schemes at internal nodes to carry out flow admission control at edge gateways. The location of functional components is studied and appropriate signalling extensions to exchange load information are presented. The suitability of such signalling extensions for admission control and traffic regulation are discussed in the context of RSVP signalling. A number of questions of detail which are usually ignored by existing theory and simulation work, are examined and solutions are presented. Certain modifications to traffic control algorithms at both internal packet marking nodes and edge gateways are proposed and discussed. The functionality and correct system operation are demonstrated by experiments using the software prototype. Further, a variety of marking algorithms is compared experimentally to assess the suitability of their respective load signal for admission control of inelastic traffic and load-adaptive traffic regulation.