This paper addresses the critical issue of Quality of Service (QoS) routing for multimedia applications, such as digital video and audio, which often have stringent QoS requirements. The authors examine the basic problem of finding paths that satisfy multiple constraints and discuss the implications on routing metric selection. They present three path computation algorithms: a centralized algorithm for source routing and two distributed algorithms for hop-by-hop routing. The centralized algorithm efficiently finds paths that meet bandwidth and delay constraints, while the distributed algorithms are designed to handle resource requirements in a more flexible and scalable manner. The paper also includes a complexity analysis of the QoS routing problem, proving that finding paths with multiple constraints is NP-complete for certain metrics. The authors conclude by outlining future research directions, including integration with resource management systems, application to connection-oriented networks, and the study of algorithm convergence after failures.This paper addresses the critical issue of Quality of Service (QoS) routing for multimedia applications, such as digital video and audio, which often have stringent QoS requirements. The authors examine the basic problem of finding paths that satisfy multiple constraints and discuss the implications on routing metric selection. They present three path computation algorithms: a centralized algorithm for source routing and two distributed algorithms for hop-by-hop routing. The centralized algorithm efficiently finds paths that meet bandwidth and delay constraints, while the distributed algorithms are designed to handle resource requirements in a more flexible and scalable manner. The paper also includes a complexity analysis of the QoS routing problem, proving that finding paths with multiple constraints is NP-complete for certain metrics. The authors conclude by outlining future research directions, including integration with resource management systems, application to connection-oriented networks, and the study of algorithm convergence after failures.