Dealing with RTTs (Round Trip Time) in IQ switches has been recently recognized as a challenging problem, especially if considering distributed (multi-chip) scheduler implementation which are suited to reduce the hardware complexity in very large, high-speed, switches. Traditional iterative three-or two-phase scheduling algorithms are based on a monolithic implementation, thus allowing instantaneous information exchange among input and output selectors to determine a matching. Multichip implementation imply that information exchange among inputs and outputs is delayed by an inter-chip latency. This delay requires non-trivial modifications to scheduling algorithms to allow a fully distributed implementation while keeping good performance. We propose a new scheduling algorithm, named SRR (Synchronous Round Robin), which is suited to a fully distributed implementation and provides good performance if compared with more complex, non fully distributed, previously proposed scheduling algorithms.

In the context of Hierarchical Mobile IPv6 integrated with Fast Handover mechanism, this paper proposes two MAP selection algorithms, both based on the classification of users depending on their mobility. Furthermore an enhancement of one of the two algorithms is presented, it introduces the concept of bufferization at MAP level. Extensive simulations have been performed to analyse and investigate algorithms results.

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IQ switches store packets at input ports to avoid the memory speedup required by OQ switches. However, packet schedulers are needed to determine an I/O (Input/Output) interconnection pattern that avoids conflicts among packets at output ports. Today, centralized, single-chip, scheduler implementation are largely dominant. In the near future, the multichip scheduler implementation will be suited to reduce the hardware scheduler complexity in very large, high-speed, switches. However, the multi-chip implementation implies introducing a non-negligible delay among input and output selectors used to determine the I/O interconnection pattern at each time slot. This delay, mainly due to inter-chip latency, requires modifications to traditional scheduling algorithms, which normally rely on the hypothesis that information exchange among selectors can be performed with negligible delay. We propose a novel multicast scheduler, named IMRR, an extension of a previously proposed multicast scheduling algorithm named mRRM, making it suitable to a multi-chip implementation, and examine its performance by simulation.

Abstract. The 95th percentile billing mechanism has been an industry de facto standard for transit providers for well over a decade. While the simplicity of the scheme makes it attractive as a billing mechanism, dramatic evolution in traffic patterns, associated interconnection practices and industry structure over the last two decades motivates an obvious question: is it still appropriate? In this paper, we evaluate the 95 th percentile pricing mechanism from the perspective of transit providers, using a decade of traffic statistics from SWITCH (a large research/academic network), and more recent traffic statistics from 3 Internet Exchange Points (IXPs). We find that over time, heavy-inbound and heavy-hitter networks are able to achieve a lower 95th-to-average ratio than heavy-inbound and moderate-hitter networks, possibly due to their ability to better manage their traffic profile. The 95 th percentile traffic volume also does not necessarily reflect the cost burden to the provider, motivating our exploration of an alternative metric that better captures the costs imposed on a network. We define the provision ratio for a customer, which captures its contribution to the provider's peak load.