Computer Networks

Welcome to ELEC S332 Computer Networks.

This is a ten-credit, higher-level course. It focuses on the concepts and technologies in computer networks. By studying this course, you will be able to understand the functions of the 5-layer Internet model and how applications trigger activities in the various layers of a computer network. ELEC S332 is delivered using a custom textbook, supplemented by a Study Guide, HKMU's Online Learning Environment (OLE) and face-to-face sessions. The study units, readings, activities and assignments in this course will help you master the topics over a period of 32 weeks.

Course organization

The overall aims of ELEC S332 Computer Networks are to:

• Teach you the basic principles, technologies and practices of computer networks using the 5-layer Internet model.
• Enable you to describe the functions and design issues of individual protocol layers of the 5-layer Internet model.
• Equip you with a basic understanding of network security issues and threats, and the means to overcome them.
• Illustrate how computer networks are used for supporting some typical business applications.

Course learning outcomes

Upon completion of ELEC S332 Computer Networks, you should be able to:

• Define computer networking concepts, basic terminology, and applications.
• Explain application-layer concepts, protocol principles, and network applications such as the WEB, HTTP and FTP.
• Elaborate on transport-layer concepts and their relationship to network- and application-layer services such as the principles of Reliable Data Transfer.
• Explain the network-layer concepts related to data forwarding, operation of routers, network control, routing principles, algorithms, and SDN.
• Analyse and illustrate link-layer concepts, protocols, and services such as error-detection and correction, addressing, and multiple-access techniques.
• Develop an awareness of the main issues involved in network security and differentiate between the characteristics of various Internet multimedia applications.

Course overview

The following chart gives a general overview of the course structure.

In this custom textbook approach, different learning modules have been carefully selected by the course team from an up-to-date commercially published textbook on computer networking and organized into a specially designed textbook for ELEC S332 students. The textbook introduces basic principles of computer networks and its applications in everyday life.

In addition to the customized textbook, you will be working through the course using HKMU-produced Study Guide in eight units. The Study Guide leads you through your study pathway unit by unit, providing commentary on each textbook chapter and supplementary self-assessment opportunities.

The third main place you will refer to for learning resources during the course is HKMU's Online Learning Environment (OLE). As well as accessing electronic versions of the study units, you will also be able to discuss topics with other students and your tutor on the course discussion board and submit your assignments online.

This course is further supported by regular face-to-face meetings.

The custom textbook

The custom textbook is based on selected chapters from the following textbook published by Pearson.

The Study Guide will indicate at which point you should read each chapter of the custom textbook.

The Study Guide

The Study Guide sets out your study pathway through the customized textbook and other course learning resources, and provides supplementary material and additional self-assessment opportunities. You'll therefore need to keep this document by your side as you work through the course.

The Study Guide is divided into eight units. The titles of the units and the textbook chapters they will cover are set out in the following table.

Don't panic if you don't receive all eight units at the same time. It is usual to receive study units in three, or even four, separate batches.

Each unit in ELEC S332 consists of three to four weeks' work. Please remember that you have to plan your own study schedule. It is essential that you complete your assignments on time, as they will prepare you for the examination.

The study units:

• present key issues and explain these with relevant concepts and examples;
• set and then comment on readings;
• present activities that guide your learning and reinforce your understanding of the key issues and skills;
• contain a summary of key points; and
• provide feedback and answers to activities.

The course is structured so that each unit builds upon previous knowledge. Each unit contains various ways to help you study. To get the most out of the course, you should:

1. read each study unit and the readings that accompany it;
2. test your comprehension and analytical skills by working through the activities that appear throughout the units;
3. browse the recommended websites and complete additional readings or activities, such as the Wireshark Labs on the textbook companion website (you will be given a code to access this website); and
4. complete the assignments.

If you encounter any problems, please make notes and raise these problems with your tutor as soon as possible.

A brief summary of the eight study units in ELEC S332 follows.

Unit 1 Computer networks and the Internet

In this unit, the basic terminology and concepts of computer networks are introduced. The hardware and software components that make up a network are examined. After that, the delay, loss and throughput of data in a computer network will be explored and some security issues will be discussed. Students will have a general picture of the computer networks and be able to relate the network devices in daily life to the terminology of the networks.

Unit 2 The application layer

This unit will first introduce the concepts and implementation of network applications. Some key concepts, including network services required by applications, clients and servers, processes, and transport-layer interfaces will be explained. Several network applications, including the Web, email, domain name services, and peer-to-peer (P2P) file distribution, will be examined in detail. This unit will start to explore the details of protocols. Different protocols will appear frequently in the rest of the course.

Unit 3 The transport layer

This unit examines the role of the transport layer. Two important protocols in the transport layer, TCP and UDP, will be elaborated on in detail. Two sets of principles, the principle of reliable data transfer and the principle of congestion control, will be introduced. Also, the implementation of these two principles in TCP will be illustrated.

Unit 4 The network layer: the data plane

The network layer will be divided into two parts in Units 4 and 5. The router, the most important network device, will be introduced. This unit will address how a packet is processed in the router and sent out. IPv4 and IPv6 protocols are illustrated in detail. This unit also covers generalized data forwarding and software-defined networking (SDN).

Unit 5 The network layer: the control plane

This unit will mainly cover the control plane of the network layer, how a packet is forwarded among routers and how network devices are configured and managed. Two routing protocols, OSPF and BGP, will be illustrated in detail. Software-defined networking controllers will be introduced. Two network management protocols, ICMP and SNMP, will be discussed.

Unit 6 The link layer and LANs

This unit will introduce the function and the protocols of the link layer and examine error-detection and error-correction techniques. The protocol and techniques of the link layer in switched local area networks will also be discussed in detail. Ethernet, a dominant local area network technology, will be examined. Besides that, virtual local area networks (VLANs) and multiprotocol label switching (MPLS) are two advanced techniques that are introduced.

Unit 7 Security in computer networks

This unit will introduce the fundamental cryptography techniques and explain how the fundamental cryptography principles work to build secure networking protocols in email transmission, TCP connections and wireless networks. This unit will also explore the security issues of networks in an organization, e.g. how to prevent attacks, and where to set up firewalls and intrusion detection systems.

Unit 8 Multimedia networking

This unit will mainly introduce the terminology of multimedia applications and classify the multimedia applications into three categories: streaming stored audio/video, conversional voice/ video-over-IP, and streaming live audio/video. This unit will also explain the characteristics and principles of these three categories. Skype, a popular voice/video-over IP application, will be discussed in detail in a case study.

The OLE

ELEC S332 will maintain an OLE presence comprising course notices and a discussion board, and other resources to facilitate the online dimension.

Other online resources

You may be referred to relevant websites and online videos to supplement your understanding of the materials.

Equipment needed (IT resources)

You will need to have access to a computer with an Internet connection.

Assignments

Assignments for this course can be found in the OLE. The nature of these assignments is described in the 'Assignments' section of this Course Guide. You are required to complete your assignments and send them on the OLE to your tutor in accordance with the timetable provided in the Presentation Schedule.

Presentation Schedule

The Presentation Schedule for this course can be found on the course OLE. In this schedule, you will see the approximate time for your tutor's receipt of your assignments.

Formal assessment for ELEC S332 consists of two components:

• assignments, which contribute 50% to your final mark; and
• an end-of-course examination, which contributes 50% to your final mark.

Assignments

Assignments serve three purposes:

1. To provide a mechanism for you to check your progress and make sure that you can meet the objectives of each unit.
2. To provide you with the chance to demonstrate your understanding of the course materials.
3. To provide an opportunity for you to apply what you have learned.

The assignments will be designed to let you demonstrate your proficiency throughout the course.

There are four assignments in ELEC S332. The marks of the four assignments will count toward your overall assessment score. The combined score of your four assignment marks contributes 50% to the total course mark.

After your tutor marks your assignments, he or she will return them to you so that you can check your learning and clarify any misunderstandings. You should carefully read through the feedback that your tutor gives on your assignments.

How to do your assignments

For each assignment, please carefully read through the question and the instructions. Please make sure you understand what is required before attempting an assignment. If you do not understand an assignment or the instructions, please contact your tutor.

Once you have completed each assignment, you may submit it through the OLE. Please make sure that each assignment reaches your tutor on or before the deadline. However, if you cannot finish your assignment on time, you must contact your tutor before the deadline to discuss the possibility of an extension. Your tutor may grant you an extension of up to seven days. If more time is needed, you must obtain approval from the Course Coordinator through the course webpage or the Dean of the School of Science and Technology. Please use the online (Web) assignment extension application. No marks will be awarded for any late assignments without prior approval obtained from the Course Coordinator or the Dean.

Assignment schedule

Final examination and grading

The final (closed book) examination for this course will be of three hours' duration and will count for 50% of the total course grade. You should use the time between finishing the last unit and the examination to review the entire course. You might find it useful to review your unit activities, assignments and your tutor's comments on them before sitting for the examination. You will be advised of the examination arrangements after you send in your examination registration card.

The final examination covers information from all parts of the course and will be in a form you have already experienced in activities and assignments. Do not worry that the examination will contain tricky questions. That would not be consistent with the clear, open approach HKMU takes to helping its learners succeed in their studies.

To earn a pass grade for the course, an overall mark of 40% or better is required, but you must attain an average mark of 40% or better on the assignments and a mark of 40% or better on the final examination. You are therefore required to submit all assignments and to sit for the examination. If, for some good reason, you are not able to complete all assignments or sit for the examination, contact your Course Coordinator to see if alternative arrangements can be made.

The table below summarizes the assessment requirements for ELEC S332.

Many kinds of support are available to you during the course. They include:

• direct personal support; and
• electronic support.

Direct personal support

The course supports you through telephone tutoring, tutorials and surgeries.

Tutors

Each student is assigned a personal tutor. Your assignments will be marked and commented on by your tutor, who will keep an eye on your progress and assist you if you encounter problems during the course. Marked assignments will be returned to you as soon as possible.

It is a good practice to keep a copy of each assignment submitted for marking, so that you can always refer any queries to the tutor during telephone conversation. Hence, please contact your tutor should the following arise:

1. You do not understand any part of the study units or the assigned readings.
2. You have any difficulty with self-tests.
3. You have a question or problem with the assignments, or with your tutor's comments or grading on an assignment.

Telephone tutoring

When you have any difficulties in your studies, you may consult your tutor by telephone in the assigned time slots. The total number of hours that you can receive telephone-tutoring services is up to four hours per week. During the telephone tutoring, you can seek advice on the study topics, guidance in assignments, and help in preparing for the examination.

Tutorials

The course includes ten tutorial meetings of two hours each — 20 contact hours in total. The tutorials are conducted to provide an opportunity for you to receive some course progress guidance from the tutors. In addition, you have an opportunity to share your study experiences and difficulties in your peer-to-peer group discussions. Although the tutorials are not compulsory, you are encouraged to attend the tutorial meetings as far as possible.

Details of the dates, times and location of the tutorials as well as the name and phone number of your tutor will be sent to you in due course.

Surgeries

As a supplement to the telephone tutoring, the course also supplies ten surgery sessions. An on-duty tutor chairs each surgery. Each surgery aims to provide face-to-face consultation on individual students' study problem areas. You may bring along to the surgeries any queries on the study units, assignments and specimen examination paper.

Electronic support

Electronic mail

You may also submit your study problems to your assigned tutor through email.

Email provides flexibility to both tutors and students in overcoming the limitations of telephone tutoring for solving more technical issues.

OLE

As mentioned earlier, a course webpage will be established through the OLE for disseminating the latest information on the course, course announcements, course scheduling, and assignment distribution.

ELEC S332 Computer Networks is intended to provide you with an understanding of the protocols and activities in the various layers of a computer network. It is a custom textbook based course supported by eight study units as well as face-to-face sessions and the course OLE. In order to understand the contents of this course, you must analyse the course materials and apply the concepts learned. We hope that you achieve great success and satisfaction from this course.

The Study Guide for this course has been prepared by two developers:

Dr Alan Yeung is an associate professor at City University of Hong Kong. He received his PhD    in Information Engineering from The Chinese University of Hong Kong in 1995. Yeung has spent over 30 years in teaching, managing, designing and research on different areas of computer networks. As an educator, Yeung has taught various subjects related to computer networks and has successfully supervised six PhD graduates. As an active researcher, he has published over 100 papers in refereed journals and conference proceedings. As an industrial consultant, he frequently provides consultancy services to the networking industry. Yeung has professional qualifications including Chartered IT Professional (CITP), Cisco Certified Network Professional (CCNP), and Cisco Certified Academy Instructor (CCAI). He is also a Certified Ethical Hacker (CEH), a EC- Council Certified Security Analyst (ECSA), a Certified Pentest Laboratory Tester (CPLT), and the co-author of the book Network Infrastructure Security.

Dr Fan Yan has both research and teaching experience in computer network-related areas. She received her PhD in Electronic Engineering from City University of Hong Kong in 2014. Yan has published academic papers in international journals and presented her findings in conferences. She has worked at the University of California, Riverside as a researcher. She has also been a module leader for a course about computing and IT management at the Hong Kong Technology Institute. At the same time, Yan has been involved in local IT startup companies using her innovative ideas to boost a robust and creative community.