126,486 research outputs found
High-speed, in-band performance measurement instrumentation for next generation IP networks
Facilitating always-on instrumentation of Internet traffic for the purposes of performance measurement is crucial in order to enable accountability of resource usage and automated network control, management and optimisation. This has proven infeasible to date due to the lack of native measurement mechanisms that can form an integral part of the network‟s main forwarding operation. However, Internet Protocol version 6 (IPv6) specification enables the efficient encoding and processing of optional per-packet information as a native part of the network layer, and this constitutes a strong reason for IPv6 to be adopted as the ubiquitous next generation Internet transport.
In this paper we present a very high-speed hardware implementation of in-line measurement, a truly native traffic instrumentation mechanism for the next generation Internet, which facilitates performance measurement of the actual data-carrying traffic at small timescales between two points in the network. This system is designed to operate as part of the routers' fast path and to incur an absolutely minimal impact on the network operation even while instrumenting traffic between the edges of very high capacity links. Our results show that the implementation can be easily accommodated by current FPGA technology, and real Internet traffic traces verify that the overhead incurred by instrumenting every packet over a 10 Gb/s operational backbone link carrying a typical workload is indeed negligible
A Web-Based Distributed Virtual Educational Laboratory
Evolution and cost of measurement equipment, continuous training, and distance learning make it difficult to provide a complete set of updated workbenches to every student. For a preliminary familiarization and experimentation with instrumentation and measurement procedures, the use of virtual equipment is often considered more than sufficient from the didactic point of view, while the hands-on approach with real instrumentation and measurement systems still remains necessary to complete and refine the student's practical expertise. Creation and distribution of workbenches in networked computer laboratories therefore becomes attractive and convenient. This paper describes specification and design of a geographically distributed system based on commercially standard components
Leveraging Program Analysis to Reduce User-Perceived Latency in Mobile Applications
Reducing network latency in mobile applications is an effective way of
improving the mobile user experience and has tangible economic benefits. This
paper presents PALOMA, a novel client-centric technique for reducing the
network latency by prefetching HTTP requests in Android apps. Our work
leverages string analysis and callback control-flow analysis to automatically
instrument apps using PALOMA's rigorous formulation of scenarios that address
"what" and "when" to prefetch. PALOMA has been shown to incur significant
runtime savings (several hundred milliseconds per prefetchable HTTP request),
both when applied on a reusable evaluation benchmark we have developed and on
real applicationsComment: ICSE 201
Development of a scalable generic platform for adaptive optics real time control
The main objective of the present project is to explore the viability of an
adaptive optics control system based exclusively on Field Programmable Gate
Arrays (FPGAs), making strong use of their parallel processing capability. In
an Adaptive Optics (AO) system, the generation of the Deformable Mirror (DM)
control voltages from the Wavefront Sensor (WFS) measurements is usually
through the multiplication of the wavefront slopes with a predetermined
reconstructor matrix. The ability to access several hundred hard multipliers
and memories concurrently in an FPGA allows performance far beyond that of a
modern CPU or GPU for tasks with a well defined structure such as Adaptive
Optics control. The target of the current project is to generate a signal for a
real time wavefront correction, from the signals coming from a Wavefront
Sensor, wherein the system would be flexible to accommodate all the current
Wavefront Sensing techniques and also the different methods which are used for
wavefront compensation. The system should also accommodate for different data
transmission protocols (like Ethernet, USB, IEEE 1394 etc.) for transmitting
data to and from the FPGA device, thus providing a more flexible platform for
Adaptive Optics control. Preliminary simulation results for the formulation of
the platform, and a design of a fully scalable slope computer is presented.Comment: Paper presented as part of SPIE ICOP 2015 Conference Proceeding
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