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Abstract-The diverse service requirements of emerging Internet applications foster the need for flexible and scalable IP quality-of-service (QoS) schemes. Due to its simplicity and scalability, DiffServ is expected to be widely deployed across the Internet. Though DiffServ supporting scheduling algorithms for output-queueing (OQ) switches have been widely studied, there are few DiffServ scheduling algorithms for input-queueing (IQ) switches. In this paper, we propose the dynamic DiffServ scheduling (DDS) algorithm for IQ switches to provide dynamic bandwidth allocation for DiffServ classes. The basic idea of DDS is to schedule EF and AF traffic according to their minimum service rates with the reserved bandwidth and schedule AF and BE traffic fairly with the excess bandwidth. We evaluate the performance of DDS under bursty traffic arrivals and compare it with PQWRR, an existing scheduling algorithm suitable for supporting DiffServ for OQ switches. Simulations results show that DDS provides minimum bandwidth guarantees for EF and AF traffic and fair bandwidth allocation for BE traffic. DDS also achieves the delay and jitter performance for EF traffic close to that of PQWRR and the delay performance for AF traffic better than that of PQWRR at high loads. Using comparatortree based arbitration components, it is feasible to implement DDS in hardware at high speed.

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Abstract-We study the connection capacity of a class of rearrangeable nonblocking (RNB) and strictly nonblocking (SNB) networks with/without crosstalk-free constraint, model their routing problems as weak or strong edge-colorings of bipartite graphs, and propose efficient routing algorithms for these networks using parallel processing techniques. This class of networks includes networks constructed from Banyan networks by horizontal concatenation of extra stages and/or vertical stacking of multiple planes. We present a parallel algorithm that runs in Oðlg 2 NÞ time for the RNB networks of complexities ranging from OðN lg NÞ to OðN 1:5 lg NÞ crosspoints and parallel algorithms that run in Oðminfd à lg N; ffiffiffiffi ffi N p gÞ time for the SNB networks of OðN 1:5 lg NÞ crosspoints, using a completely connected multiprocessor system of N processing elements. Our algorithms can be translated into algorithms with an Oðlg N lg lg NÞ slowdown factor for the class of N-processor hypercubic networks, whose structures are no more complex than a single plane in the RNB and SNB networks considered.