292,377 research outputs found
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
PhyNetLab: An IoT-Based Warehouse Testbed
Future warehouses will be made of modular embedded entities with
communication ability and energy aware operation attached to the traditional
materials handling and warehousing objects. This advancement is mainly to
fulfill the flexibility and scalability needs of the emerging warehouses.
However, it leads to a new layer of complexity during development and
evaluation of such systems due to the multidisciplinarity in logistics,
embedded systems, and wireless communications. Although each discipline
provides theoretical approaches and simulations for these tasks, many issues
are often discovered in a real deployment of the full system. In this paper we
introduce PhyNetLab as a real scale warehouse testbed made of cyber physical
objects (PhyNodes) developed for this type of application. The presented
platform provides a possibility to check the industrial requirement of an
IoT-based warehouse in addition to the typical wireless sensor networks tests.
We describe the hardware and software components of the nodes in addition to
the overall structure of the testbed. Finally, we will demonstrate the
advantages of the testbed by evaluating the performance of the ETSI compliant
radio channel access procedure for an IoT warehouse
A QoS-configurable failure detection service for internet applications
International audienceUnreliable failure detectors are a basic building block of reliable distributed systems. Failure detectors are used to monitor processes of any application and provide process state information. This work presents an Internet Failure Detector Service (IFDS) for processes running in the Internet on multiple autonomous systems. The failure detection service is adaptive, and can be easily integrated into applications that require configurable QoS guarantees. The service is based on monitors which are capable of providing global process state information through a SNMP MIB. Monitors at different networks communicate across the Internet using Web Services. The system was implemented and evaluated for monitored processes running both on single LAN and on PlanetLab. Experimental results are presented, showing the performance of the detector, in particular the advantages of using the self-tuning strategies to address the requirements of multiple concurrent applications running on a dynamic environment
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