Computer and Control Engineering

FRANCESCA CUOMO
TIZIANA CATTAI

GENERAL

The course provides an overview of the organization and main functions of a telecommunications system, dealing with both aspects of digital representation of information, signals (in continuous and discrete time) and operations on signals, as well as aspects of networks and related protocols. At the end of the course the student will have fundamental knowledge on the functioning of a telecommunications system, networks and the Internet.

SPECIFIC
• Knowledge and understanding: Know the concepts underlying digital signal processing, their transmission in current telecommunications networks, access and error control protocols and network and transport protocols based on the TPC/IP suite.

• Ability to apply knowledge and understanding: being able to understand how operations on continuous and discrete time signals work, how a protocol works, which are its characterizing functions and how performance can be evaluated. Know how to carry out simple dimensioning of protocols at the various levels of a telecommunication architecture.

• Making judgements: knowing how to analyze the benefits and limitations of signal processing and operations and dimensioning of protocols or TPC/IP network configurations.

• Communication skills: knowing how to present the functionality of signal processing (correlation, sampling, analysis in the time or frequency domain) and how a network protocol works and discuss its performance.

• Learning skills: In addition to the classic learning skills provided by the theoretical study of the teaching material, the way of teaching the course, in particular the exercises (also carried out on simulators and with processing software), stimulate the student towards procedural analysis and quantitative understanding of the functioning of a network and its protocols, facilitating the concrete application of the notions and techniques learned during the course.

KNOWLEDGE AND UNDERSTANDING
Students will acquire the fundamental knowledge related to the organization and operation of telecommunications systems. In particular, they will learn the principles of digital information representation, the characteristics of continuous-time and discrete-time signals, and the main signal processing operations. They will also acquire basic knowledge of network architectures, communication protocols, and mechanisms for error control and medium access, with particular reference to the network and transport protocols of the TCP/IP suite.

APPLYING KNOWLEDGE AND UNDERSTANDING
Students will be able to apply the acquired knowledge to analyze and understand the functioning of the main signal operations, both in the time domain and in the frequency domain. They will be able to interpret how communication protocols work, identify their main functionalities, and evaluate their performance. They will also be able to address simple problems related to the dimensioning and configuration of protocols and components at different levels of a telecommunications architecture.

MAKING JUDGEMENTS
Students will develop the ability to critically analyze the solutions adopted in telecommunications systems, evaluating the benefits and limitations of different signal processing operations as well as design choices related to protocols and network configurations based on TCP/IP architectures.

COMMUNICATION SKILLS
Students will be able to clearly describe and present the principles of signal processing, such as correlation, sampling, and analysis in the time and frequency domains, as well as the operation of network protocols. They will also be able to discuss the performance of protocols and communication systems using appropriate technical terminology.

LEARNING SKILLS
Students will develop the ability to independently deepen their understanding of topics related to telecommunications systems and communication networks. Practical activities and exercises, including the use of simulators and software tools for signal processing and network analysis, will foster a procedural and quantitative approach to studying the operation of protocols and networks, facilitating the practical application of the knowledge and techniques acquired during the course.

Basic Algebra
Logic operations and basic programming skills

1. Introduction to Communication Networks and the Internet

Evolution of network architectures and telecommunication services

Technology, Market, Standards, Regulation

Model and functions of a telecommunication network

Network services

Performance parameters

Multiplexing and resource allocation techniques

Circuit switching

Packet switching

Performance analysis models

2. Protocol Layers and Their Service Models

OSI Reference Model

TCP/IP Architecture

3. Fundamentals of Digital Representations and Communications (3 ECTS)

Introduction. Digital representation of information, concept of deterministic signal

Signal classification. Signal properties

Definition of energy and power

Operations on signals

Frequency representation of signals: Fourier Transform (continuous-time and discrete-time signals) and its properties

Convolution and correlation between signals. Energy and power spectral density

Signal transmission through systems. Properties. Impulse response

Sampling: sampling theorem, Nyquist condition. Analog-to-digital conversion. Quantization and Encoding

Baseband transmission, multilevel transmission. Noise characterization.

Shannon's capacity limit

Digital modulation: amplitude, frequency, and phase modulation. Demodulation. Quadrature Amplitude Modulation

4.1 Python Laboratory for Signal Processing

Signal definition, signal operations, correlations

Signal transmission through filters

Signal processing in the frequency domain

Digital modulations

5. Data Link Layer and Local Area Networks

Error detection and correction techniques

Parity check

Checksum

Cyclic Redundancy Check (CRC)

Multiple Access Protocols (Medium Access Control – MAC)

Wired and Wireless shared media

Multiple access techniques

Perfect access model

Random and controlled access protocols

Access protocols in wireless environments

Local Area Networks (LANs)

IEEE 802.3 Standard (Ethernet)

6. Network Layer: Data Plane

The IP protocol

Internet addressing

Classful and classless addressing

CIDR

Address resolution in the Internet

DHCP

NAT

6. Network Layer: Control Plane

Routing functions

Routing in the Internet

Routing algorithms

IGP and EGP routing protocols

Routing tables

The material is available on moodle at: https://elearning.uniroma1.it/course/view.php?id=12001

J. Kurose, K. Ross: “Reti di Calcolatori e Internet” (4° Edizione o 6° Edizione). Pearson Addison Wesley, Maggio 2008 Capitoli: 1, 3, 4, 5 e 6

A. Leon-Garcia & I. Widjaja “Communication Networks: Fundamental Concepts and Key Architecture”, McGraw-Hill Capitolo: 3

Francesca Cuomo: Esercizi di reti di telecomunicazione; Ed. Ingegneria 2000, 2005

The material is available on moodle at: https://elearning.uniroma1.it/course/view.php?id=12001

J. Kurose, K. Ross: “Reti di Calcolatori e Internet” (4° Edizione o 6° Edizione). Pearson Addison Wesley, Maggio 2008 Capitoli: 1, 3, 4, 5 e 6

A. Leon-Garcia & I. Widjaja “Communication Networks: Fundamental Concepts and Key Architecture”, McGraw-Hill Capitolo: 3

Face by face lectures on slides and other material schared during the lectures.

The attendance to the lectures is encouraged.

Examination Method (January–February session)

During the course, two midterm quizzes will be administered on Moodle (quizzes whose score can provide up to 2 + 2 bonus points, which can be used exclusively in the January or February exam session).
1. Two homework assignments will be given during the course to assess learning outcomes related to:
o digital representation and communications, and
o network configuration using the Kathará network emulation software.
(Worth 5 + 5 points)
2. A written exam in January or February, consisting of:
2.1) A section with 15 multiple-choice questions covering the theoretical part of the entire syllabus (15 points)
2.2) One numerical exercise testing the student on practical topics related to the whole syllabus (5 points)

Examination Method (from March onwards)
3. A written exam, consisting of:
3.1) A section with 15 multiple-choice questions on the theoretical part of the entire syllabus (15 points)
3.2) One numerical exercise testing the student on practical topics related to the whole syllabus (5 points)
3.3) An oral examination, following the correction of the written parts, aimed at assessing the student’s communication skills and understanding of the theoretical topics covered in the course.

To pass the exam, students must obtain a minimum grade of 18/30.
Students must demonstrate sufficient knowledge of the topics covered in the entire syllabus, assessed through the 15 multiple-choice questions, and must also be able to solve a numerical exercise, as well as process real digital signals and configure networks and protocols using network emulation software.
To obtain the maximum grade of 30/30 with honors (cum laude), students must demonstrate an excellent knowledge of all the topics covered during the course, showing the ability to connect them in a logical and coherent way.

An exercise on network configurations, routing, data fragmentation, transfer delay (worth 5 points)

15 multiple-choice questions. Each is worth 1 point:
Example multiple-choice questions:

1. Indicate which statement is false. In packet switching, if a data flow is divided into multiple packets:
a) Packets belonging to the same flow may follow different paths in the network
b) Packets belonging to the same flow may be treated differently
c) Packets belonging to the same flow are all treated in the same way

2. Suppose that after sampling an analog music track of 3 minutes with a bandwidth of 30 kHz, a file of size 16,200 kB is obtained. How many bits per sample were used in the analog-to-digital conversion?
a) 12
b) 24
c) 3

3. In an ARQ GO-BACK-N error correction protocol, a transmitting entity A with a transmission window
Ws=7
W
s
​

=7 has already sent the frames with sequence numbers 4, 5, 6, 7, and receives an acknowledgment with
Rnext=7
R
next
​

=7. Which frames will be sent next, assuming A has them available and that no timer of previous frames has expired?
a) Frames with sequence numbers 8–9–10
b) Frames with sequence numbers 4–5–6–7–8–9–10
c) Frames with sequence numbers 7–8–9–10

4. Consider the following Class C address: 192.168.0.0/24. Suppose the network is divided into 32 subnets. Which subnet does the address 192.168.0.140 belong to?
a) Subnet 192.168.0.136
b) Subnet 192.168.0.139
c) Subnet 192.168.0.128

5. Consider an IP fragment with a header of 20 bytes, total length of 600 bytes, MF (More Fragments) bit = 0, and Fragment Offset = 18. What was the total length of the original packet from which this fragment was generated (recall that the Fragment Offset is expressed in units of 8 bytes)?
a) 5952 bytes
b) 764 bytes
c) 744 bytes

6. In a LAN operating with the CSMA/CD MAC protocol, determine the maximum transfer capacity such that a minimum-length MAC frame of 10 bytes allows the correct functioning of the protocol, ensuring “collision detection.” Assume a segment length of 0.4 km with a propagation speed of 200,000 km/s.
a) 40 Mbit/s
b) 20 Mbit/s
c) 2.5 Mbit/s

7. In a private network there is a NAT with public IP address 151.100.122.3. A host with private address 192.168.0.10 accesses a web server on TCP destination port 80 with source TCP port 1025. What will be the “destination IP” and “port number” fields of the TCP segments that the web server sends back to the host in the private network?
a) Destination IP: 151.100.122.3, Destination port necessarily TCP 1025
b) Destination IP: 151.100.122.3, Destination port: the one assigned by the NAT, possibly different from TCP 1025
c) Destination IP: 192.168.0.10, Destination port necessarily TCP 1025