Tcp

LTE (Long Term Evolution) networks have been introduced in 3GPP (Third Generation Partnership Project) release 8 specifications, with an objective of high-data-rate, low latency
and packet-optimized radio access technology. This paper analyses the possibilities, capabilities and features of EstiNet Network Simulator and Emulator that can be used for modelling and analysing the behaviour of LTE networks. It also illustrates a simple scenario where one or several LTE User Equipment (UEs) are connected to Internet, and evaluates the throughput performance for TCP and UDP traffic in downlink direction. Some important LTE network parameters are also specified for this performance evaluation. Finally it will be concluded that EstiNet is a suitable simulation and emulation tool for modelling and analysing the behaviour of LTE networks.

Titanium and its alloys are widely used as implant materials. Their integration in the bone is in general very good without fibrous interface layer. However, titanium and its alloys have certain limitations. Metal ions are released from the implant alloy and have been detected in tissues close to titanium implants. The release of these elements, even in small amounts, may cause local irritation of the tissues surrounding the implant. Cell and tissue responses are affected not only by the chemical properties of the implant surface, but also by the surface topography or roughness of the implants. To overcome the problem of ion release and to improve the biological, chemical, and mechanical properties, many surface treatment techniques are used. Any surface treatment that would elicit favorable response from tissues can be applied to enhance the usefulness of the implants. In view of this, the current review describes surface modification of titanium and titanium alloys by ion beam implantation.

Current wireless sensor devices are facing a lot of issues to integrate with the global internet communication networks due to incompatible Application messaging protocols. Currently various heterogeneous application messaging protocols are available like HTTP, MQTT, COAP, DDS, AMQP. Each of this application messaging protocols are designed and implemented as per different application requirements considering the computational resources and available communication bandwidth. These protocols are not suitable for constrained sensor devices due to limitation of computational power and bandwidth. MQTT protocol is designed and implemented for Machine to Machine communication, but still not suitable for low power sensor devices due to complex TCP transport protocol used. More Efficient MQTT-SN protocol is (Message Queue Telemetry Transport-Sensor Network) proposed for sensor devices considering the wireless sensor network characteristics, power constraint and bandwidth limitations. MQTT-SN messages are transported using less over head UDP Transport Protocol. In this paper we are provided the procedure how the MQTT-SN Gateway Integration with Industry standard AWS MQTT-Server and End to End Sensor Data Transmission from Sensor Device to the IOT Application through MQTT-SN Gateway and AWS(Amazon Web Services) MQTT Server.

Abstract: Audio/Video Streaming services enable us to watch videos or listen to music from anywhere and from any web enabled multimedia device like our personal computers or smart phones. All that the user requires other than a personal computer or a smart device are Internet connection and a user account on the service’s website. This will allow users to enjoy music anytime-while driving a car, taking an evening walk etc.. The need for Multimedia streaming arises from the following factors: First, storage capacities of our devices are limited .It is not possible to store all our favourite music/video files in them. Also new songs/videos are being added to the already existing list of millions of songs/videos on a weekly or monthly basis. Therefore, it is more convenient to stream from a service to our personal computers or smart devices connected to the Internet by logging into our account. Also, the need to frequently update the songs/videos on each device independently is eliminated. This saves time and money. Secondly, we are moving towards high quality audio/video. Streaming enables us to consume high quality audio/video without the need of high end hardware on the consumer side. Thus, it leads to reduced reduce hardware cost. We will discuss in this paper, how streaming works and the protocols and codecs associated with audio/video streaming. An improvement over the currently used model is suggested. Finally, we will discuss the challenges and legal issues related with multimedia streaming.
Keywords: Streaming, protocol, codec, cloud, service, copyright, TCP, UDP, RTSP, RTP, RTCP, P2P.
Title: Multimedia Streaming and Related Issues
Author: Sober Lourembam, Venkatata Rajesh M, Meina Singh
International Journal of Computer Science and Information Technology Research
ISSN 2348-120X (online), ISSN 2348-1196 (print)
Research Publish Journals

Providing reliable data communications over wireless channels is a challenging task because time-varying wireless channel characteristics often lead to bit errors. These errors result in loss of IP packets and, consequently, TCP segments encapsulated into these packets. Since TCP cannot distinguish packet losses due to bit corruption from those due to network congestion, any packet loss caused by wireless channel impairments leads to unnecessary execution of the TCP congestion control algorithms and, hence, sub-optimal performance. Automatic Repeat reQuest (ARQ) and Forward Error Correction (FEC) try to improve communication reliability and reduce packet losses by detecting and recovering corrupted bits. Most analytical models that studied the effect of ARQ and FEC on TCP performance assumed that the ARQ scheme is perfectly persistent (i.e., completely reliable), thus a frame is always successfully transmitted irrespective of the number of transmission attempts it takes. In this paper, we develop an analytical cross-layer model for a TCP connection running over a wireless channel with a semi-reliable ARQ scheme, where the amount of transmission attempts is limited by some number. The model allows to evaluate the joint effect of stochastic properties of the wireless channel characteristics and various implementation-specific parameters on TCP performance, which makes it suitable for performance optimization studies. The input parameters include the bit error rate, the value of the normalized autocorrelation function of bit error observations at lag 1, the strength of the FEC code, the persistency of ARQ, the size of protocol data units at different layers, the raw data rate of the wireless channel, and the bottleneck link buffer size.

The performance of a distributed system is affected by the various functions of its components. The interaction between components such as network nodes, computer systems and system programs is examined with special interest accorded to its effect on system reliability. At affordable time and space costs, the analytic hierarchy process (AHP) is used to determine how the reliability of a distributed system may be controlled by appropriately assigning weights to its components. Illustrative case studies, that display the system structure, the assignment of weights and the AHP handling are presented.

In this paper an effort has been made to study various Congestion control techniques used for reducing/easing the level of congestion and subsequently avoiding the congestion of the wired communication networks in general and High Speed Networks in particular. Many authors have suggested several congestion control techniques [2], [3], [4], [8], [12], [14], [15], [23], [29], [32] & [33] and studied their behavior under various network conditions, for a range of parameters also under heterogeneous networking environments. A special effort has been made to study the problems associated with the TCP congestion control mechanisms and the several solutions that have been proposed to improve its performance. This analysis tries to study the limitations of the suggested solutions, based on various parameters and propose algorithms to overcome these limitations for the High Speed Networks.

This paper presents a novel mathematical model for the TCP Tragedy of the Commons, using Game Theory concepts. This tragedy may appear in a TCP/IP-based network when hosts do not respect the protocol rules and try to monopolize the shared network resources by using a selfish strategy. Our model quantifies the effects of this evil behavior in a simple and standard network topology and allows to obtain some interesting results which we prove formally. Finally, we validate the model results by comparing its predictions with a set of ...

The current congestion control mechanism used in TCP has difficulty reaching full utilization on high speed links, particularly on wide-area connections. For example, the packet drop rate needed to fill a Gigabit pipe using the present TCP protocol is below the currently achievable fiber optic error rates. HighSpeed TCP was recently proposed as a modification of TCP’s congestion control mechanism to allow it to achieve reasonable performance in high speed wide-area links. In this research, simulation results showing the performance of HighSpeed TCP and the impact of its use on the present implementation of TCP are presented. Network conditions including different degrees of congestion, different levels of loss rate, different degrees of bursty traffic and two distinct router queue management policies were simulated. The performance and fairness of HighSpeed TCP were compared to the existing TCP and solutions for bulk-data transfer using parallel streams.