Domaine de collision

Résumé

Un domaine de collision est une zone logique d'un réseau informatique où les paquets de données peuvent entrer en collision entre eux, en particulier avec le protocole de communication Ethernet. Un domaine de collision peut être un seul segment de câble Ethernet, un seul concentrateur ou même un réseau complet de concentrateurs et de répéteurs. Description Généralement, un concentrateur forme un seul domaine de collision alors qu'un commutateur ou un routeur en crée un par port, ce qui réduit les risques de collision. Lorsque l'Ethernet est utilisé en mode full-duplex, il n'y a plus de domaine de collision, car aucune collision n'est possible. Notes et références Articles connexes

Carrier Sense Multiple Access with Collision Detection (CSMA/CD)
Domaine de diffusion
Analyseur de paquets

Catégorie:Réseau informatique Catégorie:Ethernet

Source officielle

https://fr.wikipedia.org/wiki/Domaine_de_collision

À propos de ce résultat

Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.

Publications associées (4)

Publications associées

Chargement

Personnes associées

Chargement

Unités associées

Chargement

Concepts associés (12)

Concepts associés

Chargement

Cours associés (2)

Cours associés

Chargement

Séances de cours associées (3)

Séances de cours associées

Chargement

Cross-Layer Based Analysis of Multi-Hop Wireless Networks

Tarik Tabet

In this work, we revisit classical packet radio networks with a modern treatment of physical-layer (PHY) procedures, medium-access (MAC) and geographic channel-driven routing protocols. Our network model assumes that nodes are randomly distributed on the plane according to a homogeneous spatial Poisson process, using which we provide a novel representation of interference statistics resulting from packet collisions. Using this representation, we develop a cross-layer analysis methodology which allows multi-hop routing protocols to be treated using generic information-theoretic models for the underlying PHY/MAC procedures. These models inherently characterize modern procedures such as channel code rate adaptation, incremental redundancy and packet combining/capture. These models further allow for the assessment of the tradeoff between spatial throughput, measured in bit-meters per signal-space dimension, the range of each transmission and the average transmission delay. A generic formulation based on system parameters, such as system bandwidth, propagation models, etc., is given to analyze this tradeoff in an operational setting which can be used to build system simulators for such networks. Finally, from a purely PHY perspective, the results of this work show that coding and incremental retransmission provide a means for reliable communication coupled with a completely decentralized multiple-access strategy.

2010

Chargement

Destination buffer analysis for packets rejection obliteration in multi-channel networks

Georgia Fragkouli

In this paper we study a multi-channel network, each station of which is equipped with a network interface that has a receiver buffer of multiple packets. In this way, each station is able to receive multiple packets per time instant. We adopt a synchronous access protocol which is affected by the collisions over the multiple channels and the destination conflicts. The proposed protocol performance crucially depends on the size of the receiver buffer since it determines the packet rejection probability at destination. An analytical probabilistic model based on a Markovian process is adopted for the performance measures derivation by means of closed mathematical formulas. The proposed protocol is compared to relative ones that either totally ignore the receiver collisions or assume a receiver buffer of a single packet capacity. The numerical results show that the increase of the receiver buffer size improves the performance decisively, resulting in higher throughput and lower delay and rejection probability. Also, it is shown that the appropriate receiver buffer size per station in order for the rejections at destination to be effectively eliminated is not unlimited but is limited to three packets for 0.1% accepted maximum level of rejection probability. (C) 2019 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.

2019

Chargement

, ,

Recent theoretical results show that it is optimal to allow interfering sources to transmit simultaneously as long as they are outside a well-defined exclusion region around a destination and to adapt the rate to interference. In contrast, interference from inside the exclusion region needs to be controlled. Furthermore, when a source transmits, it should do so at maximum power. Based on these theoretical findings, we propose a cross-layer design of MAC and physical layer and present a fully distributed, rate adaptive MAC protocol for ultra-wide band (UWB) where sources constantly adapt their channel codes (and thus their rate) to the level of interference experienced at the destination. To mitigate the interference of sources inside the exclusion region, we propose a specific demodulation scheme that cancels most of the interfering energy. This scheme is entirely local to a destination and involves no protocol action. In contrast, existing MAC designs for UWB are either based on mutual exclusion, where no other communication is possible within the same collision domain, or based on power control. Through simulation we show that we achieve a significant increase in network throughput compared to traditional MAC proposals. Overall, we find that existing proposals do not fully take advantage of the specific nature of an ultra-wide band physical layer.

2004

Chargement