Comparative Study Of The VMTP, XTP, and TP4 Protocols And Their Functionalities From The Perspective Of The OSI Reference Model: Investigation Of OSI Protocols For Distributed Interactive Simulation

Report presents a comparative study of three communication protocols at the transport layer of the communication protocol stack, focusing on the similarities and differences of these three protocols in terms of transport layer functions

Significant factors in the adoption of electronic mail applications by foreign language educators

Computer-based technology with its many applications is being regularly used by our society, and is gradually becoming integrated into schools. Computer use in foreign language education, although shown to support second language acquisition, does not, however, appear to be keeping up with that of many other disciplines;This study is comprised of three papers. The first paper, Technology in Foreign Language Education: Potential Challenges and Possible Solutions, presents a description foreign language educators\u27 use of computer technologies and advantages of their use of electronic mail. The second paper, Factors that Affect the Adoption and Use of Electronic Mail by K-12 Foreign Language Educators, compares questionnaire responses on electronic mail use by K-12 foreign language teachers instructed to use electronic mail during summer workshops and foreign language teachers who did not participate in the workshops. The third paper, Post-Institute Connections: Implementation and Outcomes of a Diffusion-Based Electronic Mail Instructional Model describes the diffusion-based instructional model and triangulates an evaluation of 759 participant electronic mail messages, a final evaluation report of the 1994 institutes, and data from the second paper;Results from this study suggest that diffusion-based electronic mail instruction presented during four summer foreign language workshops promoted electronic mail adoption by participants. The study describes a diffusion-based electronic mail instructional model that integrates the use of technology directly into the general curriculum of the workshop. Electronic mail was introduced to workshop participants to provide them with an efficient means to communicate with group members as they completed a post-institute collaborative project;Participants\u27 motivation to establish an efficient means of communication assisted them in overcoming obstacles involved in setting up and learning to use an electronic mail account. Workshop electronic mail instruction and participants\u27 desire to continue communication following the workshop were found to be a significant factor in their adoption. Other significant factors included their interest to use technology, electronic mail\u27s efficiency as a communication medium, and the potential use of electronic mail with students. In-service education factors that participants considered significant included curriculum-oriented instruction

A Survey on Internet Protocol version 4 (IPv4)

Internet Protocol version 4 (IPv4) is an internetwork protocol that is active at the internet layer according to the TCP/IP model, it was developed in 1981 within a project managed by Defense Advanced Research Projects Agency. In the following years, the use of IPv4 grew to dominate data networks around the world, becoming the backbone of the modern Internet. In this survey, we highlight the operation of the protocol, explain its header structure, and show how it provides the following functions: Quality of service control, host addressing, data packet fragmentation and reassembly, connection multiplexing, and source routing. Furthermore, we handle both address-related and fragmentation-related implementation problems, focusing on the IPv4 address space exhaustion and explaining the short and long terms proposed solutions. Finally, this survey highlights several auxiliary protocols that provide solutions to IPV, namely address resolution, error reporting, multicast management, and security

DVCL:A Distributed Virtual Computer Lab for Security and Network Education

Teaching networking and IT security in higher education requires a safeplayground for students, where they can safely carry out hands-on exercises.This safe playground is known as a computer lab. Universities have todesign and to provide such a lab with respect to certain criteria, e.g.technical opportunities, educational requirements and demands of thelearners. Since there is no one-size-fits-all lab, the labs will be designed tofit into a certain context and thus have own strengths and weaknesses.In this thesis, we investigate and work with two established labs, whichwere designed for hands-on experiences in networking and it security courses.These labs are predominantly different but have an essential overlap ineducational requirements.One lab is developed by the Open University. It is dedicated for distancelearning. It is based on virtualization and every student is able to startthis lab on his own computer. Students can work out exercises wheneverand wherever they want. A shortcoming however is that students have towork alone, (distant) group work is not possible due to the isolated labarchitecture. This lab is the technical base for our research.The other lab is developed by the Cologne University. It is a physicallab, dedicated for on-campus courses and thus it is not portable. Butstudents can meet in the lab, work in groups and are able to get supportfrom a course advisor, who is also able to verify exercises. A shortcominghowever is that students must be present (they have to travel to theuniversity) and they are dependent on the opening hours of the laboratoryand the availability of the course advisers.In two research parts, we show how such two different lab approachescan be combined and what can be achieved.The first research part is about design issues.Initially, we enable group work in our lab for distance education, sincegroup work is an essential part in on-campus classes. Also remote studentsshould be able to work together. Since the lab is designed as an isolatedsystem, the challenge is to connect two of them on the network level butwithout creating a potential bridge between the isolated and the outsideworld. We achieved this by adding a communication interface to the labarchitecture. This communication interface consists of a ghost host toextract and inject network packets, and a remote bridge endpoint, totransport these packets between remote ghost hosts across an intermediateconnection, e.g. the internet. The developed prototype is called DistributedVirtual Computer Lab (DVCL) and enables to connect two or more distantlabs while preserving the isolated character.The DVCL is then extended and improved by a central authority (CA).While the point-to-point connection of the communication interface canconnect two remote networks in a handy way, more connections requirecareful planning by the students. We show that a CA simplifies the usageof our DVCL for the students (and also for academic staff) and in additionto it avoids administrative configuration errors while connecting remotelabs, e.g. a circular flow which leads to an unusable lab.The first part is completed by two applicability enhancements. Thefirst enhancement covers and resolves security issues in order to pushour prototypical implementation of the DVCL and the CA closer to aproductive learning environment. The second enhancement introduces aGraphical User Interface to increase the usability of the DVCL.The second research part is about educational aspects.In the first part, we assume that working independent from a physicalon-campus lab as well as group work is essential for our students. Ourevaluation of more than 200 students participating in an on-campus networkingcourse shows, that nearly half of the students actually say, thatthey would like to work independently from the university at least partiallyand they would welcome the introduction of an e-learning system. Inaddition, a predominant majority think of working in groups as well asreceiving guidance and feedback as crucial to their learning success. Thisresult justifies and confirms our research and also reveals an additional requirement.The challenge is to provide feedback and guidance to a student, who isworking on an exercise and a human course advisor is not available. Thisis e.g. when students use the DVCL at home in the evening hours. Weshow, that captured network traffic of a lab can give some indication ofwhat a student has already configured according to a certain exercise. Weuse this insight to develop an Electronic Exercise Assistant. This softwareprogram is able to recognize the progress of an exercise and can provideappropriate feedback and support, based on preloaded rules and conditions.This significantly improves the learning situation for students workingremotely in lab. Besides this automatic support, the exercise assistant canverify intermediate and complete solutions of an exercise.The second part is completed by an educational enhancement. Ourevaluation and also own observations show, that a lab is more than aroom with computer and network facilities. Rather it is a social placewhere students e.g. meet, form learning groups, talk and discuss. Weuse these insights and enhance the DVCL to support social interactions.Based on our on-campus lab as source, we model a set of communicational,organizational as well as educational activities and implement them in ourDVCL. The result shows, that our DVCL prototype is no longer a technicalplatform but a virtual place, where students can meet, communicate,arrange learning groups, exchange experiences and work on exercises.This thesis shows that aspects of our two different lab environments canbe combined. Our resulting Distributed Virtual Computer Lab incorporatesstrengths of each source lab. It is a gain for distance teaching as well as foron-campus classes. Remote students are now able to utilize the lab being avirtual classroom, where they can learn in groups, assisted by an electronicadvisor and without the need for a face-to-face meeting. On-campus classescan offer students a new learning environment, where they can learn in aclassroom character without the need to travel to the university

Large-Scale Client/Server Migration Methodology

The purpose of this dissertation is to explain how to migrate a medium-sized or large company to client/server computing. It draws heavily on the recent IBM Boca Raton migration experience. The client/server computing model is introduced and related, by a Business Reengineering Model, to the major trends that are affecting most businesses today, including business process reengineering, empowered teams, and quality management. A recommended information technology strategy is presented. A business case development approach, necessary to justify the large expenditures required for a client/server migration, is discussed. A five-phase migration management methodology is presented to explain how a business can be transformed from mid-range or mainframe-centric computing to client/server computing. Requirements definition, selection methodology, and development alternatives for client/server applications are presented. Applications are broadly categorized for use by individuals (personal applications) or teams. Client systems, server systems, and network infrastructures are described along with discussions of requirements definition, selection, installation, and support. The issues of user communication, education, and support with respect to a large client/server infrastructure are explored. Measurements for evaluation of a client/server computing environment are discussed with actual results achieved at the IBM Boca Raton site during the 1994 migration. The dissertation concludes with critical success factors for client/server computing investments and perspectives regarding future technology in each major area