8,697 research outputs found
Frameworks for Protocol Implementation
This paper reports on the development of a catalogue of frameworks for protocol implementation. Frameworks are software structures developed for a specific application domain, which can be re-used in the implementation of various different concrete systems in this domain. By using frameworks we aim at increasing the effectiveness of the protocol implementation process. We assume that whenever protocols are directly implemented from their specifications one may be able to increase the correctness and the speed of the implementation process, and the maintainability of the resulting system. We argue that frameworks should match the concepts underlying the techniques used for specifying protocols. Consequently, we couple the development of frameworks for protocol implementation to the investigation of the different alternative design models for protocol specification. This paper presents the approach we have been using to develop frameworks, and illustrates this approach with an example of framework
Quality of Service over Specific Link Layers: state of the art report
The Integrated Services concept is proposed as an enhancement to the current Internet architecture, to provide a better Quality of Service (QoS) than that provided by the traditional Best-Effort service. The features of the Integrated Services are explained in this report. To support Integrated Services, certain requirements are posed on the underlying link layer. These requirements are studied by the Integrated Services over Specific Link Layers (ISSLL) IETF working group. The status of this ongoing research is reported in this document. To be more specific, the solutions to provide Integrated Services over ATM, IEEE 802 LAN technologies and low-bitrate links are evaluated in detail. The ISSLL working group has not yet studied the requirements, that are posed on the underlying link layer, when this link layer is wireless. Therefore, this state of the art report is extended with an identification of the requirements that are posed on the underlying wireless link, to provide differentiated Quality of Service
Recursive SDN for Carrier Networks
Control planes for global carrier networks should be programmable (so that
new functionality can be easily introduced) and scalable (so they can handle
the numerical scale and geographic scope of these networks). Neither
traditional control planes nor new SDN-based control planes meet both of these
goals. In this paper, we propose a framework for recursive routing computations
that combines the best of SDN (programmability) and traditional networks
(scalability through hierarchy) to achieve these two desired properties.
Through simulation on graphs of up to 10,000 nodes, we evaluate our design's
ability to support a variety of routing and traffic engineering solutions,
while incorporating a fast failure recovery mechanism
Mobility through Heterogeneous Networks in a 4G Environment
Serving and Managing users in a heterogeneous environment. 17th WWRF Meeting in Heidelberg, Germany, 15 - 17 November 2006. [Proceeding presented at WG3 - Co-operative and Ad-hoc Networks]The increase will of ubiquitous access of the users to the requested services points towards the integration of heterogeneous networks. In this sense, a user shall be able to access its services through different access technologies, such as WLAN, Wimax, UMTS and DVB technologies, from the same or different network operators, and to seamless move between different networks with active communications. In this paper we propose a mobility architecture able to support this users’ ubiquitous access and seamless movement, while simultaneously bringing a large flexibility to access network operators
Analysis domain model for shared virtual environments
The field of shared virtual environments, which also
encompasses online games and social 3D environments, has a
system landscape consisting of multiple solutions that share great functional overlap. However, there is little system interoperability between the different solutions. A shared virtual environment has an associated problem domain that is highly complex raising difficult challenges to the development process, starting with the architectural design of the underlying system. This paper has two main contributions. The first contribution is a broad domain analysis of shared virtual environments, which enables developers to have a better understanding of the whole rather than the part(s). The second contribution is a reference domain model for discussing and describing solutions - the Analysis Domain Model
Multicast Multigroup Beamforming under Per-antenna Power Constraints
Linear precoding exploits the spatial degrees of freedom offered by
multi-antenna transmitters to serve multiple users over the same frequency
resources. The present work focuses on simultaneously serving multiple groups
of users, each with its own channel, by transmitting a stream of common symbols
to each group. This scenario is known as physical layer multicasting to
multiple co-channel groups. Extending the current state of the art in
multigroup multicasting, the practical constraint of a maximum permitted power
level radiated by each antenna is tackled herein. The considered per antenna
power constrained system is optimized in a maximum fairness sense. In other
words, the optimization aims at favoring the worst user by maximizing the
minimum rate. This Max-Min Fair criterion is imperative in multicast systems,
where the performance of all the receivers listening to the same multicast is
dictated by the worst rate in the group. An analytic framework to tackle the
Max-Min Fair multigroup multicasting scenario under per antenna power
constraints is therefore derived. Numerical results display the accuracy of the
proposed solution and provide insights to the performance of a per antenna
power constrained system.Comment: Presented in IEEE ICC 2014, Sydney, AUS. arXiv admin note:
substantial text overlap with arXiv:1406.755
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