Telecommunication Networks and Laboratory

(Undergraduate Course)

Objectives

This course aims at providing in a clear and cutting-edge manner the basic notions on telecommunication networks, with a special emphasis on computer networks and the TCP/IP protocol suite. The course also provides the very first analytical tools for performance evaluation.

Prerequisites

A course covering the basics of communication theory and a probability theory course are strongly recommended.

Course syllabus

Terminology, basic concepts and tools for the analysis (2 CFU)
- Classification of telecommunication networks
- Switching techniques: circuit and packet switching, datagram and virtual circuit networks
- Performance metrics: throughput, delay, jitter, packet loss
- Layered architectures
- The ISO/OSI model, the concept of protocol and of connectionless/connection-oriented protocols
- TCP/IP protocol stack, an overview
- Packet delivery time and the adoption of the ping and tracert commands to experimentally determine the Round Trip Time (RTT) and the path undertaken by packets in an IP network
(14 hours)

First modeling tools for network performance evaluation
- Poisson process, exponential distribution and the memoryless property
- Main properties of Poisson processes (homogeneity, superposition and decomposition)
- Exercises about the exponential random variable
(6 hours)

Physical and data-link layers (3 CFU):
- RS-232 and USB system
- Copper and fiber access networks
- ADSL modem functionalities
(5 hours)
- Point-to-point links and the Automatic Repeat Request (ARQ) procedures stop-and-wait, go-back-N and selective-repeat
- Throughput evaluations for such procedures
- Point-to-Point Protocol (PPP)
(6 hours)
- Access techniques to a shared communication channel: static, random, on demand
- Time Division Multiple Access (TDMA) and Frequency Division Multiple Access (FDMA)
- Relation between throughput and average packet delay for TDMA and FDMA
- Pure and slotted Aloha, access strategies of the Carrier Sense Multiple Access (CSMA) family
- Traffic-throughput relation for pure Aloha, slotted Aloha and non-persistent CSMA
(10 hours)
- IEEE 802 project: Ethernet LAN 802.3, Fast Ethernet/802.3u and Gigabit Ethernet
- Address Resolution Protocol (ARP), ARP cache and ARP packet format
- Hub and bridge functionalities
(6 hours)

Network and transport layer (2 CFU)
- Internet: the standardization process and the Requests for Comments (RFCs)
- Internet Protocol version 4 (IPv4), datagram format and addressing scheme
- Subnetting and supernetting. Examples of host routing tables
- Examples and exercises on IPv4 addressing
(11 hours)
- Transmission Control Protocol (TCP). TCP segment format and associated functionalities. Port numbers and end-points.
- Opening and closing phase of a TCP connection. TCP algorithms: slow start, congestion avoidance, fast recovery and fast retransmit
- User Datagram Protocol (UDP)
- Domain Name System (DNS)
(7 hours)

Laboratory experiences centered on the following topics (2 CFU)
- Employing Wireshark, the network protocol analyzer, to capture and inspect traffic in a broadcast wired LAN
- Relying on the Dynamic Host Configuration Protocol (DHCP) to automatically assign IP addresses
- Linux operating system: basic operating tools
- How to configure a network interface card. Creating a default route and adding static routes in the routing table of hosts and routers
- Capture and analysis of ARP traffic
(18 hours)

The splitting of the hours and credits among the different topics is indicative and may be subject to modest variations.
 

Teaching methods

The adopted teaching methods include:
- classroom lessons, where interaction is sought between the instructors and the students;
- practical experimentations, that students will perform in small groups.

Students are warmly encouraged to attend the class, although the attendance is not mandatory.

Reference texts

M.L. Merani, M. Casoni, W. Cerroni, "Hands on Networking - from Theory to Practice", ed. Cambridge University Press.

In concomitanza dell’inizio delle lezioni, sul portale Moodle vengono inoltre rese disponibili:
i. le slide in formato pdf utilizzate per le lezioni frontali e le esercitazioni in laboratorio
ii. il modello predefinito per la stesura delle relazioni di laboratorio.
 

Verification of learning

The exam consists of a written test and some laboratory reports, to hand in by January 15.
During the first decade of November, a first intermediate test is offered, covering the first part of the program. If the student scores at least 18 out of 30, she/he is allowed to access the second intermediate test, positioned before the Christmas holidays and covering the second part of the program. Given this second test is also attributed a score at least equal to 18, then the average between the two determines the score of the written test.
As an alternative, the student can take the complete written test during the year.
Laboratory reports contribute to the final grade for an additional 1, 2 or 3 points, depending on their accuracy and correctness.
Should the student estimate her/his final grade unsatisfactory, she/he can ask for an oral exam.
Structure of the intermediate written tests: three to four open questions, covering the theoretical topics and also requiring the solution of problems similar to those discussed during the class, for a total of 25 points; ten closed questions (e.g., multiple choice quizzes), for a total of 5 points. For the multiple choice questions, every answer scores 0.5 points if correct, 0 if it is not given, -0.5 if it is wrong.
Structure of the complete written test: same as for the intermediate test, with different points attributed to the open and multiple choice questions, 27 and 3, respectively.
Duration of the written test: two hours, closed books.
Do bring your calculator.

Expected results

The class provides the students with the necessary competences to critically face the analysis of telecommunication networks and to perform simple projects of IP networks.
In greater detail, at the end of the class the students will:
- know the RS-232 standard and the USB system
- know the ARQ procedures to be employed on point-to-point links
- know the standards and the devices to make cabled LANs
- know the principles underlying communications over the Internet and the main Internet protocols
- be able to estimate the throughput of the main ARQ procedures
- be able to determine the achievable throughput and the delay exhibited by several access strategies to a common communication channel
- be able to capture and analyze traffic through Wireshark
- be able to perform addressing plans in IPv4 networks
- be able to configure hosts and routers in simple networks.