There has been a great deal of interest recently in load-balancing switches due to their simple architecture and high forwarding bandwidth. Nevertheless, the mis-sequencing problem of the original load-balancing switch hinders the performance of underlying TCP applications. Several load-balancing switch designs have been proposed to address this mis-sequencing issue. They solve this mis-sequencing problem at the cost of either algorithmic complexity or special hardware requirements. In this paper, we address the mis-sequencing problem by introducing a three-stage load-balancing switch architecture enhanced with an output load-balancing mechanism. This three-stage load-balancing switch achieves a high forwarding capacity while preserving the order of packets without the need of costly online scheduling algorithms. Theoretical analyses and simulation results show that this three-stage load-balancing switch provides a transmission delay that is upper-bounded by that of an output-queued switch plus a constant that depends only on the number of input/output ports, indicating the same forwarding capacity as an output-queued switch.

As the demand on the Internet bandwidth keeps increasing, all-optical network architectures emerge as a promising solution to high-speed telecommunication networks. However, the performance of optical routers/switches is sensitive to the statistics of Internet traffic due to their limited buffer size, which weakens the optical routers' capability of absorbing Internet traffic surges (known as burstiness), resulting in a high packet drop rate and, hence, lowering the quality of service. As a natural solution to the Internet traffic burstiness, pacing has long been studied and a variety of pacing techniques have been proposed in the literature. Nevertheless, the effect of pacing has not been conclusive. In this paper, we aim to answer the following questions: (1) in what situation pacing is beneficial, (2) does pacing harm short-lived flows, (3) does pacing affect the established fairness? We adopt in our simulation a newly proposed queue length-based pacing technique as a cure to the burstiness. The experimental results show that with appropriate parameter settings, pacing (1) significantly improves the performance of a moderately loaded small-buffer network, (2) brings little negative impact on short-lived flows in a nearly drop-free environment, and (3) is able to maintain the same fairness as achieved on the current Internet. These observations are of significant importance to a potentially wide adoption of small-buffer all-optical networks.

Packet losses in the network have a considerable performance impact on transport-layer throughput. For reliable data transfer, lost packets require retransmissions and thus cause very long delays. This tail of the packet delay distribution causes performance problems. There are several approaches to trading off networking resources up-front to reduce long delays for some packets (e.g., forward error correction, network coding). We propose packet pacing as an alternative that changes traffic characteristics favorably by adding intentional delay in packet transmissions. This intentional delay counters the principle of best effort but can reduce the burstiness of traffic and improve overall network operation - in particular in network with small packet buffers. As a result, pacing improves transport-layer performance, providing a tradeoff example where small amounts of additional delay can significantly increase connection bandwidth. We present a Queue Length Based Pacing (QLBP) algorithm that paces network traffic using a single queue and that can be implemented with small computational and memory overhead. We present a detailed analysis on delay bounds and the quantitative impact of QLBP pacing on network traffic. Through simulation, we show how the proposed pacing technique can improve connection throughput in small-buffer networks.

For the optical packet-switching routers to be widely deployed in the Internet, the size of packet buffers on routers has to be significantly small. Such small-buffer networks rely on traffic with low levels of burstiness to avoid buffer overflows and packet losses. We present a pacing system that proactively shapes traffic in the edge network to reduce burstiness. Our queue length based pacing uses an adaptive pacing on a single queue and paces traffic indiscriminately where deployed. In this work, we show through analysis and simulation that this pacing approach introduces a bounded delay and that it effectively reduces traffic burstiness. We also show that it can achieve higher throughput than end-system based pacing.

The demand for more bandwidth has lead to proposals for an all-optical network core. Due to inherent constraints of optical technology, only routers with small packet buffers are feasible to be implemented. In order to ensure efficient operation of such small-buffer networks, it is necessary to ensure that traffic is less bursty than in conventional networks. We propose a novel packet pacing mechanism that can smooth traffic bursts. Our theoretical analysis shows that our pacing scheme can guarantee that queue length of routers is BIBO stable. Experimental results from our prototype implementation show the effectiveness of our pacer on in terms of reduced network congestion and improving network throughput.

Recently there has been a great deal of interest in load-balancing switches due to their simple architecture and high bandwidth. In this paper we propose a three-stage load- balancing switch along with output load-balancing to address the mis-sequencing problem. We show that our proposed scheme provides a delay guarantee bounded by the delay of an OQ switch with the same input traffic plus a constant while achieving 100% throughput for admissible traffic with (sigma, rho) -upper constraint.