Design and evaluation of a bandwidth broker that provides network quality of service for grid applications

The term computational Grid is used to describe a problem solving environment in which geographically and organizationally dispersed resources are integrated into a common infrastructure. Building computational Grids requires the existence of a resource management framework that provides a unique and secure interface to the reservation and allocation capabilities offered by the various local resource management systems. In this context, the properties of the interconnecting network are of major importance, because the actual service parameters such as bandwidth or latency are a result of the cooperation of all related network domains. The provision of service guarantees over an IP-based network can be achieved by applying a different forwarding treatment for selected packets. The Differentiated Services architecture defines a framework for implementing a scalable service differentiation in the existing Internet by an aggregation of flows to a small number of different traffic classes with a particular forwarding treatment. While this concept allows an efficient provision of service guarantees, the actual service parameters depend on the dynamic composition of the traffic classes. Here, a specific management entity, called bandwidth broker, comes into place. A bandwidth broker controls the dynamic access to traffic classes for a single trust domain and can thus be viewed as resource management system for the resource “network”. The integration of a bandwidth broker into a general resource management framework of computational Grids is therefore a natural extension. This dissertation evolves a flexible bandwidth broker architecture with the goal to incorporate the network as a manageable resource into a Grid resource management infrastructure. The presented framework intermediates between the unique requirements of emerging Grid applications and the applicable forwarding treatment of packets by considering the complex trust relationships and usage policies that can apply in a multi-domain network environment. The accomplishment of the approach is the secure and transparent end-to-end integration of a composition of bilaterally interrelated bandwidth brokers. The implementation of a prototype and a thorough experimental evaluation validates the feasibility and flexibility of the architectural design.