Cross-layer Loss Differentiation Algorithm to Improve TCP Performances in WLANs

International audienceLoss Differentiation Algorithms (LDA) are currently used to determine the cause of packet losses with an aim of improving TCP performance over wireless networks. In this work, we propose a cross-layer solution based on two LDA in order to classify the loss origin on an 802.11 link and then to react consequently. The first LDA scheme, acting at the MAC layer, allows differentiating losses due to signal failure caused by displacement or by noise from other loss types. Moreover, in case of signal failure, it adapts the behavior of the MAC layer to avoid a costly end-to-end TCP resolution. The objective of the second LDA scheme, which acts at the TCP layer, is to distinguish a loss due to interferences from those due to congestions and to adapt consequently the TCP behavior. The efficiency of each LDA scheme and of the whole cross-layer solution are then demonstrated through simulations

New adaptation method based on cross layer and TCP over protocols to improve QoS in mobile ad hoc network

Due to rapid growth of multimedia traffic used over the mobile ad-hoc networks (MANETs), to keep up with the progress of this constraints MANETs protocols becoming increasingly concerned with the quality of service. In view of the random mobility nodes in MANET, TCP becomes more unreliability in case of higher energy consumption and packet loss. In this paper we proposed a new optimization approach to enhance decision making of TCP based on some changes of IEEE 802.11 MAC uses cross layer approach. The aim is to minimize the impact of retransmissions of packet lost and energy consumption in order to analysed and chose the appropriate routing protocol for TCP that can be enhance QoS MANET. Our simulation results based QoS study using NS3 show that, our proposed achieves better performance of TCP in MANETs significantly, and also improved the throughput, energy consumption and facilitates the traffic transmission over routing protocol

A cross-layer architecture to improve mobile host rate performance and to solve unfairness problem in WLANs

The evolution of the Internet has been mainly promoted in recent years by the emergence and pro- liferation of wireless access networks towards a global ambient and pervasive network accessed from mobile devices. These new access networks have introduced new MAC layers independently of the legacy "wire- oriented" protocols that are still at the heart of the pro- tocol stacks of the end systems. This principle of isola- tion and independence between layers advocated by the OSI model has its drawbacks of maladjustment between new access methods and higher-level protocols built on the assumption of a wired Internet. In this paper, we introduce and deliver solutions for several pathologi- cal communication behaviors resulting from the malad- justment between WLAN MAC and higher layer stan- dard protocols such as TCP/IP and UDP/IP. Specially, based on an efficient analytical model for WLANs band- width estimation, we address in this paper the two fol- lowing issues: 1) Performance degradation due to the lack of flow control between the MAC and upper layer resulting in potential MAC buffer overflow; 2) Unfair bandwidth share issues between various type of flows. We show how these syndromes can be efficiently solved from neutral "cross layer" interactions which entail no changes in the considered protocols and standards

Cross-Layer Loss Differentiation Algorithms to improve TCP Performance in WLANs

Abstract. Loss Differentiation Algorithms (LDA) are currently used to determine the cause of packet losses with an aim of improving TCP performance over wireless networks. In this work, we propose a cross-layer solution based on two LDA in order to classify the loss origin on an 802.11 link and then to react consequently. The first LDA scheme, acting at the MAC layer, allows differentiating losses due to signal failure caused by displacement or by noise from other loss types. Moreover, in case of signal failure, it adapts the behavior of the MAC layer to avoid a costly end-to-end TCP resolution. The objective of the second LDA scheme, which acts at the TCP layer, is to distinguish a loss due to interferences from those due to congestions and to adapt consequently the TCP behavior. The efficiency of each LDA scheme and of the whole cross-layer solution are then demonstrated through simulations.

Optimisation inter-couches du protocole SCTP en réseaux ad hoc

Les protocoles de transport fiables ont été conçus pour s'adapter aux problèmes de congestion dans les réseaux filaires. Dans les réseaux ad hoc, leur fonctionnement conduit à une dégradation de performances que nous nous proposons de traiter par une adaptation à la mobilité en utilisant une méthode de communication inter-couches. Plus précisément, nous étudions l’amélioration des performances du protocole SCTP; très semblable au protocole TCP il définit un fonctionnement multihoming qui en environnement filaire améliore les performances du transfert. Nous montrons que cette option est également intéressante en réseaux ad hoc. Dans ce travail nous définissons deux modes d'adaptation: un mode local et un mode réparti. Dans un premier temps nous proposons une adaptation locale du transport selon l'état du réseau perçu par le protocole de routage. Dans un second temps, nous proposons une optimisation inverse, répartie sur les nœuds, où il s'agit d'adapter le routage au fonctionnement du protocole transport, de façon à pouvoir bénéficier du traitement multihoming de SCTP. Nous évaluons nos propositions par simulation et déterminons leur domaine de validité. Ce travail se conclut par la proposition d'une architecture d'adaptation permettant d'utiliser selon leurs domaines de validité les optimisations proposées. ABSTRACT : The utilization of reliable transport protocol over ad hoc networks leads to degraded performances due to the incapacity to react to non congestion errors. We propose to treat this problem by introducing mobility adaptation with a cross layer design. More precisely, we study the performance improvement of the SCTP transport protocol. Very similar to TCP, SCTP includes a multihoming option that improves its performance in the wired networks; we show that this option is also interesting in ad hoc networks. In this thesis, two methods of adaptation are proposed: a local method and a distributed one. First, we propose a local adaptation of the transport according to the network state obtained from the routing protocol. Second, we propose a reverse optimisation, distributed on the nodes, where the routing is adapted from the transport process in such a way that it can take benefit from SCTP multihoming process. We evaluate our propositions through simulations and precise their limitations. Finally, an adaptation architecture using our propositions in function of their limitation domain is proposed to conclude our work