37,305 research outputs found
Performance Analysis of the Ethernet under Conditions of Bursty Traffic
In this paper we present a simulation study of the Ethernet performance under conditions of bursty traffic. This study is motivated by two observations: Ethernet will continue to be a widely used Local Area Network (LAN), especially as an access LAN for future high speed internet (or Broadband ISDN); and future high speed applications can best be modeled as bursty sources. Bursty traffic in this study is specified using three parameters: peak bandwidth, average bandwidth, and burst factor. The simulation study shows that the inherent behavior of the Ethernet does not change with bursty traffic. That is, as long as the utilization is less than a threshold value, packet delay, is almost equal to transmission time, queue lengths are minimal, and packet delay, queue lengths, and packet loss rate increase very quickly. Although the basic trend of the Ethernet performance is the same, performance metrics deteriorate faster with bursty traffic. For example, packet loss due to collision, packet delay, and buffer sizes increase with burstiness of traffic sources. The ratio of peak to average bandwidth of traffic sources has an unexpected effect on the packet loss rate and queue lengths. At high utilization, packet loss and queue lengths are less for higher peak-to-average ratio of bursty sources
Web Conferencing Traffic - An Analysis using DimDim as Example
In this paper, we present an evaluation of the Ethernet traffic for host and
attendees of the popular opensource web conferencing system DimDim. While
traditional Internet-centric approaches such as the MBONE have been used over
the past decades, current trends for web-based conference systems make
exclusive use of application-layer multicast. To allow for network dimensioning
and QoS provisioning, an understanding of the underlying traffic
characteristics is required. We find in our exemplary evaluations that the host
of a web conference session produces a large amount of Ethernet traffic,
largely due to the required control of the conference session, that is
heavily-tailed distributed and exhibits additionally long-range dependence. For
different groups of activities within a web conference session, we find
distinctive characteristics of the generated traffic
Software-Defined Networks Supporting Time-Sensitive In-Vehicular Communication
Future in-vehicular networks will be based on Ethernet. The IEEE
Time-Sensitive Networking (TSN) is a promising candidate to satisfy real-time
requirements in future car communication. Software-Defined Networking (SDN)
extends the Ethernet control plane with a programming option that can add much
value to the resilience, security, and adaptivity of the automotive
environment. In this work, we derive a first concept for combining
Software-Defined Networking with Time-Sensitive Networking along with an
initial evaluation. Our measurements are performed via a simulation that
investigates whether an SDN architecture is suitable for time-critical
applications in the car. Our findings indicate that the control overhead of SDN
can be added without a delay penalty for the TSN traffic when protocols are
mapped properly.Comment: To be published at IEEE VTC2019-Sprin
Performance Measurements of Supercomputing and Cloud Storage Solutions
Increasing amounts of data from varied sources, particularly in the fields of
machine learning and graph analytics, are causing storage requirements to grow
rapidly. A variety of technologies exist for storing and sharing these data,
ranging from parallel file systems used by supercomputers to distributed block
storage systems found in clouds. Relatively few comparative measurements exist
to inform decisions about which storage systems are best suited for particular
tasks. This work provides these measurements for two of the most popular
storage technologies: Lustre and Amazon S3. Lustre is an open-source, high
performance, parallel file system used by many of the largest supercomputers in
the world. Amazon's Simple Storage Service, or S3, is part of the Amazon Web
Services offering, and offers a scalable, distributed option to store and
retrieve data from anywhere on the Internet. Parallel processing is essential
for achieving high performance on modern storage systems. The performance tests
used span the gamut of parallel I/O scenarios, ranging from single-client,
single-node Amazon S3 and Lustre performance to a large-scale, multi-client
test designed to demonstrate the capabilities of a modern storage appliance
under heavy load. These results show that, when parallel I/O is used correctly
(i.e., many simultaneous read or write processes), full network bandwidth
performance is achievable and ranged from 10 gigabits/s over a 10 GigE S3
connection to 0.35 terabits/s using Lustre on a 1200 port 10 GigE switch. These
results demonstrate that S3 is well-suited to sharing vast quantities of data
over the Internet, while Lustre is well-suited to processing large quantities
of data locally.Comment: 5 pages, 4 figures, to appear in IEEE HPEC 201
Beyond Power over Ethernet : the development of Digital Energy Networks for buildings
Alternating current power distribution using analogue control and safety devices has been the dominant process of power distribution within our buildings since the electricity industry began in the late 19th century. However, with advances in digital technology, the seeds of change have been growing over the last decade. Now, with the simultaneous dramatic fall in power requirements of digital devices and corresponding rise in capability of Power over Ethernet, an entire desktop environment can be powered by a single direct current (dc) Ethernet cable. Going beyond this, it will soon be possible to power entire office buildings using dc networks. This means the logic of âone-size fits allâ from the existing ac system is no longer relevant and instead there is an opportunity to redesign the power topology to be appropriate for different applications, devices and end-users throughout the building. This paper proposes a 3-tier classification system for the topology of direct current microgrids in commercial buildings â called a Digital Energy Network or DEN. The first tier is power distribution at a full building level (otherwise known as the microgrid); the second tier is power distribution at a room level (the nanogrid); and the third tier is power distribution at a desktop or appliance level (the picogrid). An important aspect of this classification system is how the design focus changes for each grid. For example; a key driver of the picogrid is the usability of the network â high data rates, and low power requirements; however, in the microgrid, the main driver is high power and efficiency at low cost
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