Packet loss

About: Packet loss is a research topic. Over the lifetime, 21235 publications have been published within this topic receiving 302453 citations.

Self-routing multistage switching network for fast packet switching system

Abstract: A self-routing multistage switching network for a fast packet switching system suitable for multimedia communication. The self-routing multistage switching network has packet buffer means for storing packets, provided only in an input stage and respectively connected to input ports, and switching networks having no packet storing function and provided after the packet buffer means. The self-routing multistage switching network detects beforehand while packets are transmitted therethrough whether or not the packets are transmitted therethrough instead of being discarded, reports information for identifying the packets which are transmitted instead of being discarded backward to the packet buffer means through transmission routes through which the packets have been transmitted, and deletes the packets stored in the packet buffer means and corresponding to the packets which are allowed to be transmitted through the self-routing multistage switching network after sending out the same packets. The self-routing multistage switching network is capable of transmitting a plurality of packets for a piece of comunication without entailing outrun between the packets.

Measuring the capacity of a Web server under realistic loads

Abstract: The World Wide Web and its related applications place substantial performance demands on network servers. The ability to measure the effect of these demands is important for tuning and optimizing the various software components that make up a Web server. To measure these effects, it is necessary to generate realistic HTTP client requests in a test-bed environment. Unfortunately, the state-of-the-art approach for benchmarking Web servers is unable to generate client request rates that exceed the capacity of the server being tested, even for short periods of time. Moreover, it fails to model important characteristics of the wide area networks on which most servers are deployed (e.g., delay and packet loss). This paper examines pitfalls that one encounters when measuring Web server capacity using a synthetic workload. We propose and evaluate a new method for Web traffic generation that can generate bursty traffic, with peak loads that exceed the capacity of the server. Our method also models the delay and loss characteristics of WANs. We use the proposed method to measure the performance of widely used Web servers. The results show that actual server performance can be significantly lower than indicated by standard benchmarks under conditions of overload and in the presence of wide area network delays and packet losses.

In-network aggregation trade-offs for data collection in wireless sensor networks

Abstract: This paper explores in-network aggregation as a power-efficient mechanism for collecting data in wireless sensor networks. In particular, we focus on sensor network scenarios where a large number of nodes produce data periodically. Such communication model is typical of monitoring applications, an important application domain sensor networks target. The main idea behind in-network aggregation is that, rather than sending individual data items from sensors to sinks, multiple data items are aggregated as they are forwarded by the sensor network. Through simulations, we evaluate the performance of different in-network aggregation algorithms, including our own cascading timers, in terms of the trade-offs between energy efficiency, data accuracy and freshness. Our results show that timing, that is, how long a node waits to receive data from its children (downstream nodes in respect to the information sink) before forwarding data onto the next hop (toward the sink) plays a crucial role in the performance of aggregation algorithms for applications that generate data periodically. By carefully selecting when to aggregate and forward data, cascading timers achieves considerable energy savings while maintaining data freshness and accuracy. We also study in-network aggregation's cost-efficiency using simple mathematical models. Since wireless sensor networks are prone to transmission errors and losses can have considerable impact when data aggregation is used, we also propose and evaluate a number of techniques for handling packet loss. Simulations show that, when used in conjunction with aggregation protocols, the proposed techniques can effectively mitigate the effects of random transmission losses in a power-efficient way.

A comparison study on the number of wavelength converters needed in synchronous and asynchronous all-optical switching architectures

Abstract: The objective of this study is to investigate the performances of packet-switching architectures working in a synchronous and asynchronous way; in such architectures, the packet contention is resolved in the wavelength domain and the used wavelength converters are shared. We investigate on the saving of the number of converters that the sharing technique allows to obtain in the synchronous and asynchronous architectures and compare the obtained results. These ones show that when a packet loss probability is fixed, in the synchronous case a greater number of converters is saved. In some cases, the gain is 40% more than the asynchronous case. Furthermore, in the asynchronous case, a more expensive switching matrix is needed. The analysis is performed by introducing analytical and simulation models, and when both unicast and multicast traffic scenarios are considered.

Congestion control method for a packet-switched network

Abstract: The present invention relates to a method and network for controlling congestion in a packet-switched network, comprising traffic sources, traffic destinations and network nodes, wherein a packet queue length in a network node is determined and a congestion notification is transmitted back towards the source address of an incoming data packet received at the network node, if the detected packet queue length exceeds a predetermined threshold. Then, congestion control is performed at a predetermined intermediate network node in response to the receipt of the congestion notification. Thereby, burts of source traffic can be constrained and unnecessary packet losses can be avoided already at an intermediate access node and within the network. The congestion notification message generated due to an incipient congestion is immediately routed back according to its source address. As a result, control delay time is shortened, such that buffer size requirements and number of congestion notification messages are reduced.