Frank Olaf Sem-Jacobsen

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Fat-trees are a special case of multistage interconnection networks with quite good static fault tolerance capabilities. They are however straightforwardly unable to provide local dynamic fault tolerance. In this paper we propose a network topology based on the fat-tree using two parallel networks with crossover links between them in an effort to enable(More)
Existing fat-tree routing algorithms fully exploit the path diversity of a fat-tree topology in the context of compute node traffic, but they lack support for deadlock-free and fully connected switch-to-switch communication. Such support is crucial for efficient system management, for example, in InfiniBand (IB) systems. With the general increase in system(More)
Toleration of faults in the interconnection networks is of vital importance in to days huge computer installations. Still, the existing solutions are short of being satisfactory. They require that the system defaults into a routing algorithm that is inferior to the original, either in terms of performance, or in terms of the need for virtual channels, or(More)
Cluster networks will serve as the future access networks for multimedia streaming, massive multiplayer online gaming, e-commerce, network storage etc. And for those application areas provisioning of Quality of Service (QoS) is becoming and important issue. DiffServ as specified by the IETF is foreseen to be the most prominent concept for providing(More)
The fat-tree topology has become a popular choice for InfiniBand fabrics due to its inherent deadlock freedom, fault-tolerance and full bisection bandwidth. InfiniBand is used by more than 40% of the systems on the latest Top 500 list, and many of these systems are based on a fat-tree topology. However, the current InfiniBand fat-tree routing(More)
The fat-tree topology has become a popular choice for InfiniBand enterprise systems due to its deadlock freedom, fault-tolerance and full bisection bandwidth. In the HPC domain, InfiniBand fabric is used in almost 42% of the systems on the latest Top 500 list, and many of those systems are based on the fat-tree topology. Despite the popularity of the(More)