7,095 research outputs found
Electronic and photonic switching in the atm era
Broadband networks require high-capacity switches in order to properly manage large amounts of traffic fluxes. Electronic and photonic technologies are being used to achieve this objective both allowing different multiplexing and switching techniques. Focusing on the asynchronous transfer mode (ATM), the inherent different characteristics of electronics and photonics makes different architectures feasible. In this paper, different switching structures are described, several ATM switching architectures which have been recently implemented are presented and the implementation characteristics discussed. Three diverse points of view are given from the electronic research, the photonic research and the commercial switches. Although all the architectures where successfully tested, they should also follow different market requirements in order to be commercialised. The characteristics are presented and the architectures projected over them to evaluate their commercial capabilities.Peer ReviewedPostprint (published version
OSHI - Open Source Hybrid IP/SDN networking (and its emulation on Mininet and on distributed SDN testbeds)
The introduction of SDN in IP backbones requires the coexistence of regular
IP forwarding and SDN based forwarding. The former is typically applied to best
effort Internet traffic, the latter can be used for different types of advanced
services (VPNs, Virtual Leased Lines, Traffic Engineering...). In this paper we
first introduce the architecture and the services of an "hybrid" IP/SDN
networking scenario. Then we describe the design and implementation of an Open
Source Hybrid IP/SDN (OSHI) node. It combines Quagga for OSPF routing and Open
vSwitch for OpenFlow based switching on Linux. The availability of tools for
experimental validation and performance evaluation of SDN solutions is
fundamental for the evolution of SDN. We provide a set of open source tools
that allow to facilitate the design of hybrid IP/SDN experimental networks,
their deployment on Mininet or on distributed SDN research testbeds and their
test. Finally, using the provided tools, we evaluate key performance aspects of
the proposed solutions. The OSHI development and test environment is available
in a VirtualBox VM image that can be downloaded.Comment: Final version (Last updated August, 2014
W-NINE: a two-stage emulation platform for mobile and wireless systems
More and more applications and protocols are now running on wireless networks. Testing the implementation of such applications and protocols is a real challenge as the position of the mobile terminals and environmental effects strongly affect the overall performance. Network emulation is often perceived as a good trade-off between experiments on operational wireless networks and discrete-event simulations on Opnet or ns-2. However, ensuring repeatability and realism in network emulation while taking into account mobility in a wireless environment is very difficult. This paper proposes a network emulation platform, called W-NINE, based on off-line computations preceding online pattern-based traffic shaping. The underlying concepts of repeatability, dynamicity, accuracy and realism are defined in the emulation context. Two different simple case studies illustrate the validity of our approach with respect to these concepts
Mesmerizer: A Effective Tool for a Complete Peer-to-Peer Software Development Life-cycle
In this paper we present what are, in our experience, the best
practices in Peer-To-Peer(P2P) application development and
how we combined them in a middleware platform called Mesmerizer. We explain how simulation is an integral part of
the development process and not just an assessment tool.
We then present our component-based event-driven framework for P2P application development, which can be used
to execute multiple instances of the same application in a
strictly controlled manner over an emulated network layer
for simulation/testing, or a single application in a concurrent
environment for deployment purpose. We highlight modeling aspects that are of critical importance for designing and
testing P2P applications, e.g. the emulation of Network Address Translation and bandwidth dynamics. We show how
our simulator scales when emulating low-level bandwidth
characteristics of thousands of concurrent peers while preserving a good degree of accuracy compared to a packet-level
simulator
When Should I Use Network Emulation?
The design and development of a complex system requires an adequate
methodology and efficient instrumental support in order to early detect and
correct anomalies in the functional and non-functional properties of the tested
protocols. Among the various tools used to provide experimental support for
such developments, network emulation relies on real-time production of
impairments on real traffic according to a communication model, either
realistically or not.
This paper aims at simply presenting to newcomers in network emulation
(students, engineers, ...) basic principles and practices illustrated with a
few commonly used tools. The motivation behind is to fill a gap in terms of
introductory and pragmatic papers in this domain.
The study particularly considers centralized approaches, allowing cheap and
easy implementation in the context of research labs or industrial developments.
In addition, an architectural model for emulation systems is proposed, defining
three complementary levels, namely hardware, impairment and model levels. With
the help of this architectural framework, various existing tools are situated
and described. Various approaches for modeling the emulation actions are
studied, such as impairment-based scenarios and virtual architectures,
real-time discrete simulation and trace-based systems. Those modeling
approaches are described and compared in terms of services and we study their
ability to respond to various designer needs to assess when emulation is
needed
When should I use network emulation ?
The design and development of a complex system requires an adequate methodology and efficient instrumental support in order to early detect and correct anomalies in the functional and non-functional properties of the tested protocols. Among the various tools used to provide experimental support for such developments, network emulation relies on real-time production of impairments on real traffic according to a communication model, either realistically or not. This paper aims at simply presenting to newcomers in network emulation (students, engineers, ...) basic principles and practices illustrated with a few commonly used tools. The motivation behind is to fill a gap in terms of introductory and pragmatic papers in this domain. The study particularly considers centralized approaches, allowing cheap and easy implementation in the context of research labs or industrial developments. In addition, an architectural model for emulation systems is proposed, defining three complementary levels, namely hardware, impairment and model levels. With the help of this architectural framework, various existing tools are situated and described. Various approaches for modeling the emulation actions are studied, such as impairment-based scenarios and virtual architectures, real-time discrete simulation and trace-based systems. Those modeling approaches are described and compared in terms of services and we study their ability to respond to various designer needs to assess when emulation is needed
IP-Level Satellite Link Emulation with KauNet
Distributed applications and transport protocols communicating over a satellite link may react very strongly to conditions specific to that kind of link. Providing a evaluation framework to allow tests of real implementations of such software in that context is quite a challenging task. In this paper we demonstrate how the use of the general-purpose KauNet IP-level emulator combined with satellite-specific packet loss patterns can help by reproducing losses and delays experienced on a satellite link with a simple Ethernet LAN setup. Such a platform is an essential tool for developers performing continuous testing as they provide new features for e.g. video codecs or transport-level software like DCCP and its congestion control components
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