Supports Advance Reservations and Co-Allocation

The realization of end-to-end quality of service (QoS) guarantees in emerging network- based applications requires mechanisms that support rst dynamic discovery and then ad- vance or immediate reservation of resources that will often be heterogeneous in type and implementation and independently controlled and administered. W ep r o p o s e t h eG l o b u s Architecture for Reservation and Allocation (GARA) to address the four highlighted is- sues. GARA treats both reservations and computational elements such as processes, network ows, and memory blocks as rst class entities, allowing them to be created, monitored, and managed independently and uniformly. It simpli es management of het- erogeneous resource types by deni ng uniform mechanisms for computers, networks, disk, memory, and other resources. Layering on these standard mechanisms, GARA enables the construction of application-level co-reservation and co-allocation libraries that applica- tions can use to dynamically assemble collections of resources, guided by both application QoS requirements and the local administration policy of individual resources. We describe a prototype GARA implementation that supports three dier ent resource types|parallel computers, individual CPUs under control of the Dynamic Soft Real-Time scheduler, and Integrated Services networks|and provide performance results that quantify the costs of our techniques.