A Study of Cross Layer Design compare with Layer Design for MANET

Mobile Ad – hoc networks (MANET) are becoming increasingly popular in wireless technology, especially for providing services in disaster area. Mobile users are looking forward to new technologies that allow them to communicate anytime, anywhere, and using any communication device. Mobile ad – hoc networks suffer from several performance limitations, especially related to excessive burden deriving from the layering approach for the TCP / IP protocol stack design. In fact, TCP / IP protocol stack originally designed for wired networks and it is not suitable for wireless and mobile ad hoc networks. In this paper, it focuses on cross layer network design which is especially for wireless and mobile ad hoc networks. The main objective is to how cross layer differ from layered design, cross layer design approaches, challenges of cross layer design and implementation of cross layer design based MANET. And also this article brief the readers an overview of cross layer concept while discussing different cross layer proposals given by researchers

A Study of Cross Layer Design compare with Layer Design for MANET

Mobile Ad – hoc networks (MANET) are becoming increasingly popular in wireless technology, especially for providing services in disaster area. Mobile users are looking forward to new technologies that allow them to communicate anytime, anywhere, and using any communication device. Mobile ad – hoc networks suffer from several performance limitations, especially related to excessive burden deriving from the layering approach for the TCP / IP protocol stack design. In fact, TCP / IP protocol stack originally designed for wired networks and it is not suitable for wireless and mobile ad hoc networks. In this paper, it focuses on cross layer network design which is especially for wireless and mobile ad hoc networks. The main objective is to how cross layer differ from layered design, cross layer design approaches, challenges of cross layer design and implementation of cross layer design based MANET. And also this article brief the readers an overview of cross layer concept while discussing different cross layer proposals given by researchers

TCP in Wireless Networks: Challenges, Optimizations and Evaluations TCP in Wireless Networks: Challenges, Optimizations and Evaluations

Abstract This thesis presents research on transport layer behavior in wireless networks. As the Internet is expanding its reach to include mobile devices, it has become apparent that some of the original design assumptions for the dominant transport protocol, TCP, are approaching their limits. A key feature of TCP is the congestion control algorithm, constructed with the assumption that packet loss is normally very low, and that packet loss therefore is a sign of network congestion. This holds true for wired networks, but for mobile wireless networks non-congestion related packet loss may appear. The varying signal power inherent with mobility and handover between base-stations are two example causes of such packet loss. This thesis provides an overview of the challenges for TCP in wireless networks together with a compilation of a number of suggested TCP optimizations for these environments. A TCP modification called TCP-L is proposed. It allows an application to increase its performance, in environments where residual bit errors normally give a degraded throughput, by making a reliability tradeoff. The performance of TCP-L is experimentally evaluated with an implementation in the Linux kernel. The transport layer performance in a 4G scenario is also experimentally investigated, focusing on the impact of the link layer design and its parameterization. Further, for emulation-based protocol evaluations, controlled packet loss and bit error generation is shown to be an important aspect

Optimization of transmission control protocol and feedback control mechanisms for wireless internet

University of Technology, Sydney. Dept. of Computer Systems.All current versions of reliable Transmission Control Protocol (TCP) react to packet losses differently and adjust the TCP congestion window in various ways. These protocols assume congestion in the network to be the primary cause for packet losses and unusual delays. TCP performs well over wired networks by adapting to end-to-end delays and packet losses caused by congestion. The TCP sender uses the cumulative acknowledgements it receives to determine which packets have reached the receiver, and provides reliability by retransmitting lost packets. The sender identifies the loss of a packet either by the arrival of several duplicate cumulative acknowledgements (say, three ACKs) or the absence of an acknowledgement for the packet within a timeout. TCP reacts to packet losses by reducing its transmission (congestion) window size before retransmitting packets, initiating congestion window or avoidance mechanisms and backing off its retransmission timer. These measures result in a reduction in the load on the intermediate links, thereby controlling the congestion in the network. Unfortunately, when packets are lost in the networks for reasons other than congestion, these measures result in an unnecessary reduction in end-to-end throughput and sub-optimal performance. Wireless links typically have much higher bit error rates. This implies that packet loss would occur frequently. If no error correction is attempted at lower layer, TCP will exercise its congestion control procedure unnecessarily and the throughput will be reduced significantly. If the link layer performs error control by performing the retransmission itself, packet transmission time will vary greatly, sometime even exceeding TCP retransmission time out and again TCP slow start will occur. In wireless networks, “packet loss ’’ problem is also encountered during handover when a mobile device moves from the coverage of one cell to that of another. During the handover, if the mobile station decides to make a handover before the segments are transmitted over the air interface, it is likely that some TCP segments buffered in a base station may be forwarded to another base station. This results in excessive segment delay or loss. Thus, there is a clear demand for methods that can suppress the problems caused by the wireless environment. Recently, several techniques have been developed to improve end-to-end TCP performance over wireless links. They can be classified into three categories: end-to-end TCP, split TCP and link layer TCP. However, they have not addressed these problems successfully. In this thesis, we propose, design and implement several algorithms that are applicable to the wireless networks in order to solve outstanding problems. Firstly, the research investigates the relationship between packet loss and network congestion and introduces a feedback based end-to-end congestion control algorithm to the wireless network. This algorithm is a modification of a Fair Intelligent Congestion Control (FICC) proposed in [19]. The innovation of the algorithm is to modify the original FICC in such a way that the queue lengths can be effectively controlled when it is jointly employed with TCP in the wireless network. The next algorithm is the new design of Explicit Loss Notification (ELN) at base station in Wired-Cum-Wireless networks. With the combination of new ELN algorithm and Wireless FICC algorithm, the end-to-end performance and fairness are greatly improved by eliminating the misinterpretation of error related lost packets from congestion. Finally, the research investigates the effects of network congestion, which often happens over low bandwidth wireless link, and QoS performance (e.g. fairness, delay variation) of multiple sessions of TCP traffic in a hybrid network. We propose a framework, which consists of two main algorithms, feedback based congestion control and Explicit Window Adaptation (EWA)

Performance Modeling, Design and Analysis of Transport Mechanisms in Integrated Heterogeneous Wireless Networks

Recently, wireless access to Internet applications and services has attracted a lot of attention. However, there is no single wireless network that can meet all mobile users’ requirements. Con-sequently, integrated heterogeneous wireless networks are introduced to meet diverse wireless Internet applications and services requirements. On the other hand, integrated heterogeneous wireless networks pose new challenges to the design and development of reliable transport mechanisms. Wireless Application Protocol version 2 (WAP 2.0) is one of the promising trans-port mechanisms. It uses wireless profiled TCP (WP-TCP), which is fully compatible with TCP, as one of the reliable transport protocols to cope with the wireless link impairments. For WAP 2.0 to continue providing reliable and efficient transport services in the future, one of the key is-sues is to thoroughly study, understand, and improve its performance in integrated heterogeneous wireless networks. In this thesis, we develop analytical frameworks and propose a solution to respectively study and improve the performance of WP-TCP in integrated heterogeneous wireless networks. Spe-cifically, we consider WP-TCP short- and long-lived flows over integrated wireless local area network (WLAN) and wireless wide area network (WWAN), where WLAN can be static or mo-bile. In order to facilitate the analysis of WP-TCP performance in integrated WLAN and WWAN, we first construct a novel WLAN link model, which captures the impact of both uncor-related and correlated transmission errors, and derive mathematical expressions that describe packet loss probability and packet loss burst length over WWAN-WLAN link. Then, we develop analytical frameworks for studying the performance of WP-TCP short- and long-lived flows. Differently from those reported in the literature, our analytical framework for WP-TCP short-lived flows takes into account both correlated and uncorrelated packet losses. Furthermore, our analytical framework for long-lived flow can be used to study the short-term (during vertical handover) and long-term performances of WP-TCP and it captures the effects of vertical handover, such as excessive packet losses and sudden change in network characteristics, which are commonly experienced in integrated static WLAN and WWAN. By using the devel-oped analytical frameworks, we extensively analyze the performance of WP-TCP flows and in-vestigate the optimal protocol design parameters over a wide range of network conditions. Finally, based on our analytical studies, we propose a receiver-centric loosely coupled cross-layer design along with two proactive schemes, which significantly improve the vertical hand-over performance. The proposed solution is easy to implement and deploy, compatible with tra-ditional TCP, and robust in the absence of cross-layer information. Extensive simulations have been conducted to confirm the effectiveness and practicability of our schemes

A survey of performance enhancement of transmission control protocol (TCP) in wireless ad hoc networks

This Article is provided by the Brunel Open Access Publishing Fund - Copyright @ 2011 Springer OpenTransmission control protocol (TCP), which provides reliable end-to-end data delivery, performs well in traditional wired network environments, while in wireless ad hoc networks, it does not perform well. Compared to wired networks, wireless ad hoc networks have some specific characteristics such as node mobility and a shared medium. Owing to these specific characteristics of wireless ad hoc networks, TCP faces particular problems with, for example, route failure, channel contention and high bit error rates. These factors are responsible for the performance degradation of TCP in wireless ad hoc networks. The research community has produced a wide range of proposals to improve the performance of TCP in wireless ad hoc networks. This article presents a survey of these proposals (approaches). A classification of TCP improvement proposals for wireless ad hoc networks is presented, which makes it easy to compare the proposals falling under the same category. Tables which summarize the approaches for quick overview are provided. Possible directions for further improvements in this area are suggested in the conclusions. The aim of the article is to enable the reader to quickly acquire an overview of the state of TCP in wireless ad hoc networks.This study is partly funded by Kohat University of Science & Technology (KUST), Pakistan, and the Higher Education Commission, Pakistan

milliProxy: a TCP Proxy Architecture for 5G mmWave Cellular Systems

TCP is the most widely used transport protocol in the internet. However, it offers suboptimal performance when operating over high bandwidth mmWave links. The main issues introduced by communications at such high frequencies are (i) the sensitivity to blockage and (ii) the high bandwidth fluctuations due to Line of Sight (LOS) to Non Line of Sight (NLOS) transitions and vice versa. In particular, TCP has an abstract view of the end-to-end connection, which does not properly capture the dynamics of the wireless mmWave link. The consequence is a suboptimal utilization of the available resources. In this paper we propose a TCP proxy architecture that improves the performance of TCP flows without any modification at the remote sender side. The proxy is installed in the Radio Access Network, and exploits information available at the gNB in order to maximize throughput and minimize latency.Comment: 7 pages, 6 figures, 2 tables, presented at the 2017 51st Asilomar Conference on Signals, Systems and Computers, Pacific Grove, CA, 201

MANETs: Internet Connectivity and Transport Protocols

A Mobile Ad hoc Network (MANET) is a collection of mobile nodes connected together over a wireless medium, which self-organize into an autonomous multi-hop wireless network. This kind of networks allows people and devices to seamlessly internetwork in areas with no pre-existing communication infrastructure, e.g., disaster recovery environments. Ad hoc networking is not a new concept, having been around in various forms for over 20 years. However, in the past only tactical networks followed the ad hoc networking paradigm. Recently, the introduction of new technologies such as IEEE 802.11, are moved the application field of MANETs to a more commercial field. These evolutions have been generating a renewed and growing interest in the research and development of MANETs. It is widely recognized that a prerequisite for the commercial penetration of the ad hoc networking technologies is the integration with existing wired/wireless infrastructure-based networks to provide an easy and transparent access to the Internet and its services. However, most of the existing solutions for enabling the interconnection between MANETs and the Internet are based on complex and inefficient mechanisms, as Mobile-IP and IP tunnelling. This thesis describes an alternative approach to build multi-hop and heterogeneous proactive ad hoc networks, which can be used as flexible and low-cost extensions of traditional wired LANs. The proposed architecture provides transparent global Internet connectivity and address autocofiguration capabilities to mobile nodes without requiring configuration changes in the pre-existing wired LAN, and relying on basic layer-2 functionalities. This thesis also includes an experimental evaluation of the proposed architecture and a comparison between this architecture with a well-known alternative NAT-based solution. The experimental outcomes confirm that the proposed technique ensures higher per-connection throughputs than the NAT-based solution. This thesis also examines the problems encountered by TCP over multi-hop ad hoc networks. Research on efficient transport protocols for ad hoc networks is one of the most active topics in the MANET community. Such a great interest is basically motivated by numerous observations showing that, in general, TCP is not able to efficiently deal with the unstable and very dynamic environment provided by multi-hop ad hoc networks. This is because some assumptions, in TCP design, are clearly inspired by the characteristics of wired networks dominant at the time when it was conceived. More specifically, TCP implicitly assumes that packet loss is almost always due to congestion phenomena causing buffer overflows at intermediate routers. Furthermore, it also assumes that nodes are static (i.e., they do not change their position over time). Unfortunately, these assumptions do not hold in MANETs, since in this kind of networks packet losses due to interference and link-layer contentions are largely predominant, and nodes may be mobile. The typical approach to solve these problems is patching TCP to fix its inefficiencies while preserving compatibility with the original protocol. This thesis explores a different approach. Specifically, this thesis presents a new transport protocol (TPA) designed from scratch, and address TCP interoperability at a late design stage. In this way, TPA can include all desired features in a neat and coherent way. This thesis also includes an experimental, as well as, a simulative evaluation of TPA, and a comparison between TCP and TPA performance (in terms of throughput, number of unnecessary transmissions and fairness). The presented analysis considers several of possible configurations of the protocols parameters, different routing protocols, and various networking scenarios. In all the cases taken into consideration TPA significantly outperforms TCP