Networks

The aim of this subject is to present the basic principles of the architecture of networks. The different alternatives of interconnection of networks, the layer models and the basic protocols inside every layer are studied, considering the programming of the networks in the transport and IP levels. Also, different mechanisms for the congestion control and the main routing protocols in wide area networks. The subject finishes with the study of the local area networks and the networks adaptors in the link layer level. Finally, we will complement the theoretical studies with basic implementations of some of the studied algorithms and protocols.

This is the first subject on networks that is taught in the degree so its focus is on the principles and functioning of the basic protocols. Other subjects of the degree also deal about networks, but they are focused on other aspects, such as commercial models of networks, design, management, distributed programming, etc. This first subject contributes to the basic knowledge of networks that will be in use later in the degree.

1. Introduction. In this chapter a general vision of everything that will be treated throughout the course will be given.
- Programming of sockets (TCP and UDP)
- The Internet elements (hosts, routers, connections, providers...)
- Types of protocols (connection-oriented and connectionless)
- Types of networks (diffusion, switching)
- Access to the Internet. Transmission media.
- Delays on the Internet.
- Architecture. Layer model. TCP/IP

2. Application layer. In this chapter the transmission of messages among applications are dealt: web, mail, etc, that are those which justify the requirements and the way of working of the networks.
- Servers and clients
- Services required by applications
- The web and HTTP. FTP protocol
- The e-mail. SMTP, POP3, IMAP
- Name service. DNS
- Content distribution

3. Transport layer. This chapter deals about the basic layers of the TCP/IP architecture, essential to the transmission of packages.
- General characteristics and classification
- Connectionless service. UDP
- Foundations of the reliable transfer
- Flow control: adaptive retransmission, sliding window
- Connection-oriented service. TCP
- Congestion control

4. Network layer. This is another basic layer of the TCP/IP architecture, essential in order to the packages could be directed to its destination.
- Switching techniques: datagrams, virtual circuits
- Link state and distance vector algorithms
- Routing strategies. RIP, OSPF, BGP
- Internet protocol (IP and IPv6)
- Internet Control Message Protocol (ICMP)
- Dynamic Host Configuration Protocol (DHCP)
- Network Address Translation (NAT)

5. Link layer. In this chapter it will be basically seen the functioning of the network adaptors.
- Function of the link layer
- Media access protocols. Ethernet
- Hubs, bridges and switches
- Wireless networks
- Asynchronous Transfer Mode (ATM)

Practices: TCP/IP programming in C. In the practices it will be made the programming of some of the concepts and protocols seen theoretically using the functions and structures available in C libraries (addresses, ports, name service, sockets, etc.)

Slides used in class are available on the virtual campus of USC.

Basic Bibliography:
- Kurose, James F. and Ross, Keith W. Redes de Computadores. Un enfoque descendente. 7ª edición: Pearson Educación S. A., 2017. ISBN: 978-849035-528-2. This is a self-contained book and covers all aspects of the subject. Everything necessary for understanding the subject is included, besides additional contents. It is a book about networks for computer engineers.
- Peterson, Larry L. and Davie, Bruce S. Computer networks: a systems approach. 5ª edición: Morgan Kaufmann, 2012. ISBN: 978-0-12-385059-1. This is a comprehensive book and it represents a good reference material for this subject.

Complementary Bibliography:
- Comer, D. E, Stevens, D. L., and Evangelista, M. Internetworking with TCP/IP, Vol. III: Client-Server Programming and Applications, Linux/Posix Sockets Version. Prentice-Hall. 2001. ISBN: 0130320714. One of the books which explain the socket library, used in practices, though a lot of tutorials are available on the Internet.
- Stallings, W. Comunicaciones y redes de computadores. 7ª edición: Pearson Prentice-Hall, 2013.
- Comer, D. E. and Stevens, D. L. Internetworking with TCP/IP Vol. III Client-Server Programming and Applications-Windows Sockets Version. Prentice-Hall.
- Donahoo, M. and Calvert, K. TCP/IP Sockets in C: Practical Guide for Programmers (The Practical Guides Series). 2ª edición: Morgan Kaufmann, 2009.
- Magaña, E., Izme Mendi, E., Prieto Mínguez, M., and Villadangos Alonso, J. Comunicación y Redes de Computadores. Problemas y Ejercicios Resueltos. Pearson Prentice Hall, 2003. ISBN: 8420539201.
- Barcia Vázquez, N. et. al. Redes de computadores y arquitecturas de comunicaciones: supuestos prácticos. Pearson 2005. ISBN 8420546070.

It contributes to develop the competences CG8, CG9, CG10, TR1, TR3, FB5, RI11, TI2 and TI4, contained in the memory of Degree in Computer Engineering.

More specifically, to the specific competences of this subject, it will be acquired the basic concepts of the operation of the local area networks and of the Internet and their programming with TCP/IP, that represent an important part of the competence RI11 and contribute to the competences FB5, TI2 and TI4 and to the global ones CG8, CG9 and CG10.

In addition, the following generic competences will be developed: aptitude to solve problems, capacity of analysis and synthesis, capacity of organization and planning, capacity of information management (grasp and analysis of information), taking decisions, aptitude to apply the knowledge to the practice, skill to work on an autonomous way, written expression, as part of the generic skills TR1 and TR3.

In the theoretical classes the blackboard and multimedia systems and slides will be used. The didactic methodology will be centred specially on the individual work of students.

The practices will be done in the computer science class at ETSE. It will be intended that students work individually in their accomplishment.

Furthermore it will be used, as far as possible, the facilities of the USC-Virtual. In the web page of the subject the student will be able to obtain a copy in digital format of the material used in the theoretical and practical classes, as well as supplementary material and links to web pages related to the contents of the subject.

In the lectures the competencies to work will be CG8 (through knowledge of basic topics and technologies), FB5 (by understanding the computer systems interconnection), RI11 (through the knowledge and application of the features and functionality of computer networks and the Internet), TI2 (by means of the knowledge of network technologies), and TI4 (through the knowledge of basic network and Internet protocols).

In the interactive classes competencies to work will be CG8 (through knowledge of basic materials and the use of basic technologies), CG9 (by solving practical problems), CG10 (through reporting and calculations), FB5 (by the implementation of programs to apply that studied in the lectures), RI11 (by implementing knowledge-based networking and Internet applications), TR1 (by delivery of written reports, exercises and classroom expositions), TR3 (by doing programs and exercises requiring solutions autonomously).

The assessment of learning is based on the actual implementation of continuous assessment and final examination of theory. This evaluation will be based on the interactive class attendance, on the effective achievement by students of the proposed practices throughout the semester for these classes and in conducting a final exam of all content of the subject. To pass the subject it is essential to approve both practical and the final exam.

ASSESSMENT OF COMPETENCIES

In the practical part of the subject (35% of grade) the mark of the works, reports and expositions made in the interactive classes will take into account the degree of achievement of competences CG8, CG9, CG10, FB5, RI11, TR1, and TR3.

In the theoretical part of the subject (65% of grade) competencies CG8, FB5, RI11, TI2, and TI4 will be evaluated by various questions in the theory test.


ATTENDANCE TO THE INTERACTIVE CLASSES

Given the practical nature of the matter, the interactive class attendance is mandatory to pass the subject in both opportunity Ordinary (end of the semester) and the extraordinary (July.)

The number of hours the student can skip the interactive classes without justification should not exceed 6 hours. If the student misses more than six hours without adequate justification for these faults, you will have suspended the practice. If failures occur for cause (as stated in the rules of attendance in the lessons adapted to the European Higher Education Area, adopted in CG March 25, 2010) accredited, students can choose either attempting their own practices that could not perform in the classroom or to recover those hours shifts in other practices. Monitoring of attendance at the interactive classes will be by roll-in class and attendance reflecting on a sheet of signatures.


CONTINUOUS EVALUATION OF PRACTICES

Each of the proposed practices will have a specific deadline. After that date, the practice will be considered as not done.

Based on the evaluation of practices and the submissions, there will be a mark of 0-10 on the practice. To overcome practices, you must obtain a grade of 5 or higher. In the case of obtaining a grade below 5, the student will have suspended the practice.

The practice mark will weigh 35% in the final mark of the subject.


ORDINARY OPPORTUNITY

At the end of term there will be an exam of all theoretical content of the subject. Passing this exam is a prerequisite to pass the subject. The grade obtained on this test will count 65% towards the final score.

Students who have missed more than six hours of interactive classes without adequate justification or who are suspended practice will have suspended the subject.


JULY SPECIAL OPPORTUNITY

Students who have failed the practical part may recover this part in the extraordinary opportunity of July, delivering the compulsory practices proposed during the course and also taking a practice exam.

In July there will be an exam of all theoretical content of the subject. Passing this exam is a prerequisite to pass the subject. The grade obtained on this test will count 65% towards the final score.


STATUS OF APPROVED

To pass the subject is required to fulfill all of the following conditions:

a. Attending interactive classes, under the conditions stated above.
b. Having passed the practices.
c. Have passed the theoretical exam.


STATUS OF NO ATTENDANCE

It has the status of no attendance when not attending the theory exam.


REPEATER STUDENTS

In general, repeater students must follow the same system as regular students and must attend interactive classes under the conditions stated above. In cases where the mark of the practices is higher than 7, you can save the practices of a course to another.

In the case of fraudulent performance of exercises or tests, the regulations of the Normativa de avaliación do rendemento académico dos estudantes e de revisión de cualificacións will be applied. In the application of the Normativa da ETSE sobre plaxio (approved by the ETSE Council on 12/19/2019), the total or partial copy of any practical or theory exercise will mean failure on both opportunities of the course, with a grade of 0.0 in both cases.

The convenient distribution of the hours that should be taken are:

15 hours of lectures
10 hours of learning based on problems in reduced groups.
25 hours of practices

A total of 50 hours of on-site work. The autonomous estimated work of the student is 100 hours, that include the autonomous study, writing of exercises and works, preparation of practices, assessment of works, etc.
The total of hours is 150 .

To be constant in the study and the attendance to the practices is one of the keys to study this subject. It is very important so that the subject works out to be up to date , in this way the explanations received at class will be made profitable. In addition, a serious attitude in the practices is going to allow that the concepts should be consolidated and that it could be approached exercises increasingly complicated without too much effort.

It is necessary to have previously acquired a basic knowledge of programming in language C.

Classes are taught in Spanish. Virtual Campus of USC is used. In interactive classes Linux operating system and gcc C compiler are used.