Performance-guaranteed communications over packet switching networks

The wide use of optical fiber and packet switching makes possible many new real-time distributed applications characterized by quality of service in terms of bandwidth, delay, jitter and loss rate. Packet switching network is the dominating approach to provide performance-guaranteed services in distributed application environments. This thesis addresses six scheduling and architecture problems in supporting performance-guaranteed communications over packet switching networks. In the first subject, a frame-oriented service discipline, earliest deadline first round robin (EDF-RR), is proposed for packet switches taking the advantages of lower computational complexity, tighter delay bounds and lenient buffer requirements. In the second subject, a multicast switch design is put forth by considering both architecture and service discipline for real-time multicast traffic. In the design, parallel output-queued switch architecture is employed so that non-blocking transmission of multicast traffic is achieved. In the third subject, mixed scheduling of real-time and nonreal-time traffic is investigated by expanding EDF-RR service discipline. Since packet scheduling is closely related to real-time task scheduling, proportionate fairness scheduling of periodic tasks over multiple processors with allocation constraints is investigated as the next research subject. Efficient schedulability test is studied and then an on-line approximate pfair scheduling algorithm is presented for fixed and migrating tasks. In the fifth subject, expanding EDF-RR, a service discipline called parallel fair round robin is put forward for the case of existing multiple channels in a physical data link such as optical switching networks using wavelength division multiplexing (WDM). Finally, the thesis studies real-time communications over broadcast-and-select WDM networks. The sufficient number of wavelengths is found for non-blocking transmission of unicast traffic. By applying generalized stable matching, real-time multicasting over broadcast-and-select networks is achieved in that deterministic multicast is guaranteed and network throughput is increased.