Project DIANA - Converging and integrating IP and ATM for real-time applications

The evolution of IP and ATM share some common drivers. Both of them are addressing efficient network resource utilisation. In order to evaluate the options and combinations offered by these technologies the DIANA project is looking into the areas where ATM and IP both overlap and complete each other, that is QoS interworking between ATM and IP. This is achieved by investigating RSVP-over-ATM approach. This solution is compared with two IP level approaches: Differentiated Services and Scalable Resource Reservation Protocol (SRP). The RSVP over ATM proposal creates RSVP flow aggregates with similar QoS requirements and sets up a SVC for each aggregate. This approach is best suited for end-to-end per flow QoS provisioning. The relatively complex RSVP over ATM connection set up is inefficient has for short-lived flows in a wide scale network, and the assumption of end-to-end RSVP support may be too strong. DIANA project has developed a dynamic bandwidth management solution to reduce the signalling overhead in RSVP over ATM case. The Differentiated Services framework covers a set of per hop behaviour (PHB) schemes where priority levels are set in the headers of each individual packet at domain boundaries. Packet discarding and scheduling are done in the subsequent routers. DIANA has been working on a solution called Simple Integrated Media Access (SIMA). The mechanism is very scalable and adaptive but offers only relative QoS for sender originated flows. Although SIMA is easy to manage with only two parameters, it is flexible enough to be used as an end-to-end solution in wide scale networks. The Scalable Reservation Protocol (SRP) proposal has two priority values that can be set in each packet by the sender or any subsequent router to reflect the flow status in the next link. Receivers give feedback to the senders. SRP offers adaptive and scalable reservations but can not differentiate