Ing Ind - Inf (Mag.)(ord. 270) - MI (474) TELECOMMUNICATION ENGINEERING - INGEGNERIA DELLE TELECOMUNICAZIONI
051178 - OPTICAL AND TRANSPORT NETWORKS
Communications networks have to deal with the exponential growth of traffic demand, driven by multimedia services and mobile applications requiring higher and higher bandwidth. Traditionally, network traffic used to be based on circuit-switched connections between pairs of endpoints. Today, most network traffic is packet switched, generated by a multitude of services in bursty and time-varying patterns, thus imposing more complex requirements on data transport performance. Only optical technologies enable flexible and transparent transport of various data formats at the highest transmission capacity.
This course provides an ample overview of fundamental topics about transport networks based on optical systems. In the first part, a thorough primer of traditional digital multiplexing systems (PDH and SDH) is provided. Packet data transport over optical systems is treated. Architectures of optical Next-Generation Access Networks and Passive Optical Networks are illustrated with deployment considerations.
In the second part, the subject area of network synchronization is explored, providing a wide overview on fundamental topics including jitter, clock models, network synchronization architectures and requirements in a variety of network environments.
Finally, basic elements of traffic models and engineering are surveyed, for both circuit and packet traffic, up to covering advanced topics as self-similar fractal models to describe the behavior of packet network traffic.
All course topics are presented by providing the necessary theoretical background, yet always highlighting most relevant practical and application aspects.
Risultati di apprendimento attesi
1. Knowledge and understanding
After having attended the course and having fruitfully passed the exam, the student should know at least the main elements of:
digital multiplexing systems, from PDH to SDH;
SDH systems, from frame structures to equipment and systems;
architectures of optical access networks;
how packet traffic (namely, IP) is transported over transmission systems;
principles of network synchronization, as a fundamental requirement for fixed and mobile networks;
models of synchronization signals and clocks;
models of circuit and packet traffic in transport networks.
2. Applying knowledge and understanding
Owing to the various numerical exercises discussed in class, on which at least half of the exam tests is based, the students should not only acquire the capacity to apply the concepts learned from lessons to practical cases, but also improve their ability of numerical resolution and design in practical problems, which is an essential ability for an Engineer.
Moreover, the lessons always highlight the practical and application aspects that are most relevant to the subject, thus encouraging the students to learn to apply autonomously the concepts understood to new and different problems.
5. Lifelong learning skills
The learning skills of the students are developed by an interactive approach in teaching, which always strives to involve participation and interaction and to stimulate curiosity for new topics.
When available, complete texts, such as textbooks, chapters, white papers are recommended as study material rather than succinct slides, in order to stimulate the ability of students to learn concepts on a complete text and technical documentation, rather than limiting the scope to few essential sentences condensed to few words.
Likewise, exams avoid multiple-choice questions, to develop the skills of students in active problem solving.
1. BASICS OF DIGITAL MULTIPLEXING SYSTEMS. Time Division Multiplexing (TDM). Synchronous and asynchronous digital multiplexing. Plesiochronous Digital Hierarchy (PDH).
2. SYNCHRONOUS DIGITAL HIERARCHY (SDH) SYSTEMS. Hierarchical levels. Frame structures. Examples of mapping of PDH signals over SDH. Pointer justification. Overheads. Bit error rate estimation (BIP-n,m coding). SDH equipment and sytems. Scrambling. Frame alignment. Alarms. Physical interfaces.
3. TRANSPORT OF PACKET DATA. IP over SDH. Virtual Concatenation and Link Capacity Adjustment Scheme (LCAS). Ethernet over SDH.
4. OPTICAL ACCESS NETWORKS. Legacy copper access networks. Architectures of optical Next-Generation Access Networks (NGAN). Optical access systems for FTTx. Passive Optical Networks (PON).
5. NETWORK SYNCHRONIZATION. Principles of network synchronization. Timing signals. Jitter and wander. Packet jitter and synchronization. Frame synchronization. Evolution of network synchronization from circuit to packet networks. Synchronization over packet-switched networks. Synchronization of mobile wireless networks. Principles of Network Time Protocol (NTP) and IEEE1588 Precision Time Protocol (PTP). Synchronization networks. Models of clocks in telecommunications and characterization of their stability.
6. TRAFFIC MODELS AND ENGINEERING. Elements of queuing theory: Bernoulli and Poisson events, Markov chains, birth and death processes, basic queuing systems. Circuit traffic models and engineering. Packet traffic models in transport networks: self-similarity and long-range dependence. Estimation and measurement of traffic long-range dependence.
It is recommended to attend all classroom lessons for optimal understanding of all course topics.
Fundamentals of mathematics, probability and telecommunications networks.
Modalità di valutazione
The learning assessment consists first in a written exam, including various numerical exercises and questions on the subject matter. Both are structured in such a way, to verify the "expected learning outcomes" 1, 2, and 5 as described above, in particular not only the knowledge and understanding of course topics, but also the ability of students to solve numerical problems and to design solutions.
An oral examination is usually required after the written test, based on the first assessment result achieved with it. No intermediate evaluations are planned. All exams are all-inclusive over the whole course program.
The student, who is not satisfied of the assessment score received, is admitted to next exams to improve his/her evaluation until the end of the Academic Year. Handing over a written test cancels any valid mark previously achieved.
S. Bregni, Sistemi di trasmissione PDH e SDH - Multiplazione, Editore: McGraw-Hill Education Italy, Anno edizione: 2004, ISBN: 978-8-83-867340-5
S. Bregni, Synchronization of Digital Telecommunications Networks, Editore: J. Wiley and Sons, Anno edizione: 2002, ISBN: 0-471-61550-1
Fiber to the Home Council Europe, FTTH Handbook, Ed. 7, Anno edizione: 2016
Stefano Bregni, Lecture notes (slides and selected book chapters) on all course topics, Anno edizione: 2020
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Tipo Forma Didattica
Ore di attività svolte in aula
Ore di studio autonome
Laboratorio Di Progetto
Informazioni in lingua inglese a supporto dell'internazionalizzazione
Insegnamento erogato in lingua
Disponibilità di materiale didattico/slides in lingua inglese
Disponibilità di libri di testo/bibliografia in lingua inglese
Possibilità di sostenere l'esame in lingua inglese
Disponibilità di supporto didattico in lingua inglese