Computing infrastructure issues in distributed communications systems : a survey of operating system transport system architectures

The performance of distributed applications (such as file transfer, remote login, tele-conferencing, full-motion video, and scientific visualization) is influenced by several factors that interact in complex ways. In particular, application performance is significantly affected both by communication infrastructure factors and computing infrastructure factors. Several communication infrastructure factors include channel speed, bit-error rate, and congestion at intermediate switching nodes. Computing infrastructure factors include (among other things) both protocol processing activities (such as connection management, flow control, error detection, and retransmission) and general operating system factors (such as memory latency, CPU speed, interrupt and context switching overhead, process architecture, and message buffering). Due to a several orders of magnitude increase in network channel speed and an increase in application diversity, performance bottlenecks are shifting from the network factors to the transport system factors.This paper defines an abstraction called an "Operating System Transport System Architecture" (OSTSA) that is used to classify the major components and services in the computing infrastructure. End-to-end network protocols such as TCP, TP4, VMTP, XTP, and Delta-t typically run on general-purpose computers, where they utilize various operating system resources such as processors, virtual memory, and network controllers. The OSTSA provides services that integrate these resources to support distributed applications running on local and wide area networks.A taxonomy is presented to evaluate OSTSAs in terms of their support for protocol processing activities. We use this taxonomy to compare and contrast five general-purpose commercial and experimental operating systems including System V UNIX, BSD UNIX, the x-kernel, Choices, and Xinu

Application and network traffic correlation of grid applications

Dynamic engineering of application-specific network traffic is becoming more important for applications that consume large amounts of network resources, in particular, bandwidth. Since traditional traffic engineering approaches are static they cannot address this trend; hence there is a need for real-time traffic classification to enable dynamic traffic engineering. A packet flow monitor has been developed that operates at full Gigabit Ethernet line rate, reassembling all TCP flows in real-time. The monitor can be used to classify and analyse both plain text and encrypted application traffic. This dissertation shows, under reasonable assumptions, 100% accuracy for the detection of bulk data traffic for applications when control traffic is clear text and also 100% accuracy for encrypted GridFTP file transfers when data channels are authenticated. For non-authenticated GridFTP data channels, 100% accuracy is also achieved, provided the transferred files are tens of megabytes or more in size. The monitor is able to identify bulk flows resulting from clear text control protocols before they begin. Bulk flows resulting from encrypted GridFTP control sessions are identified before the onset of bulk data (with data channel authentication) or within two seconds (without data channel authentication). Finally, the system is able to deliver an event to a local publish/subscribe server within 1 ms of identification within the monitor. Therefore, the event delivery introduces negligible delay in the ability of the network management system to react to the event

High efficiency, character-oriented, local area networks

Imperial Users onl

Business scenarios, technical challenges and system requirements - D2.1

Deliverable D2.1 del projecte Europeu OneFIT (ICT-2009-257385)Preprin

High-speed, economical design implementation of transit network router

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1995.Includes bibliographical references (p. 88-90).by Kazuhiro Hara.M.S

Modelling and Simulation of SIP and IAX Sessions

Import 03/11/2016My thesis is focused on simulating a functioning model of SIP and IAX and compare these two VoIP protocols. This is done by implementing an Asterisk server onto two virtual machines with Ubuntu operating system where I build a trunking system for each protocol, tested it by calling the peers in both directions, captured the traffic passing through and analysed it with Wireshark. The acquired data is then implemented and presented on a chart form for a better view and comparison of the two parallel protocols.Moje práce je zaměřena na simulaci funkčnosti modelu SIP a IAX a porovnání těchto dvou VoIP protokolů. To je provedeno zavedením Asteriskem serveru na dva virtuální počítaček s operačním systémem Ubuntu, kde je vybudován trunking systém pro každý protokol a to tak, že spojuje volající v obou směrech, zachycuje průchod, a analyzuje pomocí Wireshark. Získaná data jsou pak použita a prezentována ve formě grafů pro lepší přehlednost a srovnání obou paralelních protokolů.440 - Katedra telekomunikační technikydobř