Delay-centric handover in SCTP

The introduction of the Stream Control Transmission Protocol (SCTP) has opened the possibility of a mobile aware transport protocol. The multihoming feature of SCTP negates the need for a solution such as Mobile IP and, as SCTP is a transport layer protocol, it adds no complexity to the network. Utilizing the handover procedure of SCTP, the large bandwidth of WLAN can be exploited whilst in the coverage of a hotspot, and still retain the 3G connection for when the user roams out of the hotspot’s range. All this functionality is provided at the transport layer and is transparent to the end user, something that is still important in non-mobile-aware legacy applications. However, there is one drawback to this scenario - the current handover scheme implemented in SCTP is failure-centric in nature. Handover is only performed in the presence of primary destination address failure. This dissertation proposes a new scheme for performing handover using SCTP. The handover scheme being proposed employs an aggressive polling of all destination addresses within an individual SCTP association in order to determine the round trip delay to each of these addresses. It then performs handover based on these measured path delays. This delay-centric approach does not incur the penalty associated with the current failover-based scheme, namely a number of timeouts before handover is performed. In some cases the proposed scheme can actually preempt the path failure, and perform handover before it occurs. The proposed scheme has been evaluated through simulation, emulation, and within the context of a wireless environment

VOIP adoption and bussiness prospective in Bangladeh

This thesis report is submitted in partial fulfillment of the requirements for the degree of Bachelor of Science in Computer Science and Engineering, 2007.Cataloged from PDF version of thesis report.Includes bibliographical references (page 30).Voice over Internet protocol - VoIP, or IP telephony is a technology by which the routing of voice communications are done through Internet or any other Internet Protocol (IP) based networks. Here the voice data is transmitted over a general purpose packet-switched network instead of dedicated traditional circuit-switched voice transmission lines. Voice Over Internet Protocol (VoIP) is a telephony technology used to transmit ordinary telephone calls over the Internet. VoIP takes analogue audio signals and turns them into digital signals (packets) that are transmitted using Internet Protocol (IP) networks. VoIP’s advantages include low cost, flexibility, and mobility. Conversely, VoIP’s disadvantages include sound quality such as latency (delay), jitter, and packet loss. VoIP has a number of cultural, social, and regulatory impacts that solution providers must consider when marketing their services.Our target is to learn the basics of VoIP, to focus on the current problems of VoIP, to find out the solutions, to Setup a VoIP business.Md. RuhanuzzamanNahid MahmudB. Computer Science and Engineerin

Satellite system performance assessment for in-flight entertainment and air traffic control

Concurrent satellite systems have been proposed for IFE (In-Flight Entertainment) communications, thus demonstrating the capability of satellites to provide multimedia access to users in aircraft cabin. At the same time, an increasing interest in the use of satellite communications for ATC (Air Traffic Control) has been motivated by the increasing load of traditional radio links mainly in the VHF band, and uses the extended capacities the satellite may provide. However, the development of a dedicated satellite system for ATS (Air Traffic Services) and AOC (Airline Operational Communications) seems to be a long-term perspective. The objective of the presented system design is to provide both passenger application traffic access (Internet, GSM) and a high-reliability channel for aeronautical applications using the same satellite links. Due to the constraints in capacity and radio bandwidth allocation, very high frequencies (above 20 GHz) are considered here. The corresponding design implications for the air interface are taken into account and access performances are derived using a dedicated simulation model. Some preliminary results are shown in this paper to demonstrate the technical feasibility of such system design with increased capacity. More details and the open issues will be studied in the future of this research work

Unified communications: The search for ROI through tomorrow’s business communication solutions

The traditional workplace is evolving; the way in which businesses communicate today is different than it was in the past and yet is likely to change again in the future. The current state of the economy and globalization has forced every organization to review its future business plans and cut costs everywhere including communications. Organizations are seeking out technology in hopes of finding new ways to reduce their bottom-line communication costs. Today, many enterprise business infrastructures are comprised of separate networks - voice, data, and mobile - yet most of the time these networks never interact. The ability to link business applications from various networks with communications proves to be valuable and is known as convergence. Convergence is defined as the combining of one or more elements into one. Unified Communications is a concept that looks to build on convergence, although it is not a new technology. Unified Communications is the term coined by the communications industry that signifies the comprehensive integration of various communication networks for reasons of increased revenue and reduced costs. Unified Communications will fundamentally transform the way in which people work - from decreased carrier costs to increased response times, the benefits of Unified Communications greatly outweigh the investment. This thesis will analyze the adoption of the Unified Communications paradigm by examining the Unified Communications solutions of tomorrow and prove that establishing a cohesive Unified Communications strategy will indisputably have a return on investment. In doing so, solutions from four Unified Communications vendors (Microsoft, Cisco, IBM, and RIM) will be examined to expose the potential benefits available to any enterprise business. The end result will show the rate of return for reducing costs and increasing revenue to yield a positive ROI for each vendors\u27 UC solution