Learning outcomes of the course unit
Introduction to optical networking: principle and challenges.
Optical network hierarchies: core, metro and access
Introduction to the network design
Optical Transport Network (OTN)
Capacity and Flow assignment problems in communication networks
Optical switching, routers and Optical terminals
Transparent network evolution
Network survivability objectives and resiliency techniques
Automatic optical reconfiguration: from static to dynamic networks
Advantages of reconfigurable and multilayer networks
The future of optical networks: the 5G era
- Basic knowledge of programming (C, C++, Java)
- Basic knowledge of optical devices
Course contents summary
Learning outcomes of the course unit:
The objective of the course is to give to the students the basis of optical network structure, operation, and management. Students will understand which are the traffic requirements and operator choices behind a network design. In particular, the following concepts will be introduced:
- Definition of OTN networks
- Routing and grooming
- Optical reconfiguration
By applying the above-mentioned knowledge and the weekly practical work, the student will be able at the end of the course to:
- Design and plan optical communication networks
- Implement a planning tool
- Write a report with analysis of a network planning
Classes are divided into two parts: theoretical and practical lessons. During the week two classes (2 hours each) of theoretical and practical lessons alternate (hereafter odd lessons relate to theoretical classes, even to practical).
Lesson 1: Introduction to the optical networking: principle and challenges.
- Enabling technologies
- Telecom network overview
- Business models
- WDM evolution
Lesson 2: Class on network planning tools. Introduction to DIAMOND.
Lesson3: Optical Cross Connects (first part)
- Description of network topologies
- Evolution of WDM transmission devices
- Description of the basic optical elements
- Definition of optical cross connects
- Introduction to optoelectronic devices
- Concept of routing in an optical network
Lesson 4: use of DIAMOND: some simple exercise.
Lesson 5: Optical Cross Connects (second part)
- O-E-O optical cross connects
- O-O-O optical cross connects
- Optical bypass
- Definition of (R-)OADM and OXC
- Add/Drop blocks
- New generation OXC requirements
Lesson 6: Git or versioning tools for managing a project.
Lesson 7: Transparent network challenges (first part)
- Opaque vs transparent routing
- Routing definition
- Optical bypass and 3R regeneration
- Description of main optical impairments
- Coherent detection
- Transparent island and selective regeneration
- Impairment based routing
Lesson 8: Introduction to the connectivity graph
Lesson 9: Transparent network challenges (second part)
- Wavelength continuity constraints
- Routing wavelength assignment (RWA) problem
- Single step and multi-step RWA + physical impairments issues
- Connectivity graph
- RWA assignment, graph coloring and conflict graph
- Mixed line rate wavelength assignment
Lesson 10: Some study with the introduction of optical reach concept and transparent islands thanks to the connectivity graph
Lesson 11: Transparent network challenges (third part)
- Flex line rate paradigm
- Routing and spectrum assignment (RSA)
- Conflict graph for RSA problems
- Super-channel concept
- Elastic transponders
Lesson 12: Introduction to the connectivity graph, routing and wavelength assignment
Lesson 13: Grooming (first part)
- Traffic types and service capacity increase
- Sub-rate traffic management
- End-to-end multiplexing
- Aggregation rules
- Grooming definition
- Grooming vs aggregation
Lesson 14: Elastic optical network planning challenges.
Study of the impact of different function costs on the network planning
Lesson 15: Grooming (second part)
- Grooming switches
- OTN layer
- Grooming design rules
- Grooming and power consumption problem
Lesson 16: Traffic aggregation and grooming, different algorithms: connectivity graph vs routing and knapsack algorithms
Lesson 17: Optical recovery (first part)
- Introduction to survivability
- Failure terminology
- Service level agreement (SLA)
- Quality of Service (QoS)
- QoS and network optimization
- Service differentiation
- Resiliency definition: protection and restoration
- Multiple failure recovery
- Shared risk link group definition
- Routing constraints
Lesson 18: Network dimensioning with resiliency constraints. Introduction to failure scenarios.
Lesson 19: Optical recovery (second part)
- Optical and electrical protection scheme descriptions
- Client vs network resiliency
- Dedicated and shared protection
- Fauld dependent vs fault independent recovery
- Network protection at OTN layer
- Multiple concurrent failures
Lesson 20: Optical reconfiguration of a network; network failure and optical restoration.
Lesson 21: Dynamic optical networks
- Introduction to optical reconfigurations
- Evolution from static to dynamic networks
- Control plane and PCE definitions
- Where to place a control plane
- GMPLS-based operations
- Software defined networks
Lesson 22: Definition of the final project work; assisted code implementation on the work for the final project.
Lesson 23: Optical transport network (OTN) standard
- OTN objective
- OTN functionalities and ben
- Slides of the course will be available
- Material distributed by the lecturer
- Supporting books:
o B. Mukherjee, Optical Networks, Springer 2006
o J. Simmons, Optical Network design and planning, Springer 2014
Theoretical lectures will use video-projection of slides. Some exercises will be solved during the lectures. Interaction with students is welcome and will be stimulated by open questions.
Some lectures describing the software used for the planning project (Net2Plan and Git) will be given in the computer lab.
Homeworks are assigned weekly.
Assessment methods and criteria
The exam consists of an individual project which has to be presented and discussed with the instructor.
The student will design an optical network by means of a numerical simulator partially developed by the student in Java language. The student can choose between two types of project: the first concerns the planning of a static network (easier project, allowing a maximum grade of 25/30), the second the planning of a dynamic network (more complex project, allowing a maximum grade of 30/30). After having chosen the type of project, each student receives a specific planning problem to solve, whose investigation will be reported in the final project report. The project is evaluated in terms of correctness, completeness, clarity of exposition. The project is graded 1-30.
To pass the exam, a minimum score of 18 is needed.