# 182.702 Distributed Algorithms This course is in all assigned curricula part of the STEOP.\$(function(){PrimeFaces.cw("Tooltip","widget_j_id_21",{id:"j_id_21",showEffect:"fade",hideEffect:"fade",target:"isAllSteop"});});This course is in at least 1 assigned curriculum part of the STEOP.\$(function(){PrimeFaces.cw("Tooltip","widget_j_id_23",{id:"j_id_23",showEffect:"fade",hideEffect:"fade",target:"isAnySteop"});}); 2024S 2023S 2022S 2021S 2020S 2019S 2018S 2017S 2016S 2015S 2014S 2013S 2012S

2023S, VU, 4.0h, 6.0EC

## Properties

• Semester hours: 4.0
• Credits: 6.0
• Type: VU Lecture and Exercise
• Format: Presence

## Learning outcomes

After successful completion of the course, students are able to...

• understand fundamental models, problems, algorithms, lower bound and impossibility results, and proof techniques in distributed computing,
• apply lower bounds and impossibility results learned to new situations where appropriate,
• design new distributed algorithms for new situations, using the algorithms and techniques learned as building blocks, and
• find new lower bounds and impossibility results.

## Subject of course

Fault-tolerant distributed algorithms are at the heart of any distributed system for critical applications and implement low-level services like clock synchronization, group membership and consensus. Suitable algorithms must work as specified in the presence of the inherent uncertainty in network- or shared-memory coupled distributed systems, which is caused by varying/unknown communication delays and computing speeds and, in particular, subsystem failures. Due to combinatorial explosion, it is often impossible to verify the correct operation of such algorithms by means of model checking (or exhaustive testing). Correctness proofs based on formal-mathematical modelling are the only feasible alternative here.

This theoretical graduate-level basic course provides an introduction to distributed algorithms and their formal-mathematical analysis and has the following content:

• Basics: Execution runs, safety and liveness properties, causality and time;
• Models: Message passing vs. shared memory, synchronous vs. asynchronous, failure models;
• Algorithms: Leader election, mutual exclusion, clock synchronization, consensus, distributed snapshots;
• Proof techniques: Impossibility proofs, lower bounds, simulation, indistinguishability, bivalence.

## Teaching methods

The course is organized in the "anglo-american style", which is based on continuous engagement during the whole semester: Several quizzes, student presentations and homework assignments ensure (1) that the topics taught in the lecture are efficiently acquired, and (2) that the individual formal-mathematical problem-solving skills are trained. The homework assignments are treated in "mini conferences" (LaTeX solutions, reviewing, presentation in class), such that (3) these scientific soft skills are trained "hands-on" as well.

## Mode of examination

Immanent

All who want to participate in the course in the next summer term: Please subscribe to the TISS LVA-Forum & News already before the semester holidays. [Enrolling (via myTI) is only possible when the course has already started (and the admission criteria are met).]

ECTS breakdown (6 ECTS = 150 hours):

30h             Lecture time
4.5h          6 Quizzes
12h             4 Homework presentations
18h             Preparation time for 6 Quizzes
85.5h          Preparation time for 4 Homework-Assignments  (3-5 exercises each): first and final version (in LaTeX); reviewing.

## Course dates

DayTimeDateLocationDescription
Thu11:00 - 13:0002.03.2023EI 10 Fritz Paschke HS - UIW Introduction
Fri09:00 - 11:0003.03.2023 - 30.06.2023EI 10 Fritz Paschke HS - UIW Lecture
Thu13:00 - 15:0009.03.2023 - 22.06.2023EI 10 Fritz Paschke HS - UIW Lecture
Fri13:00 - 15:0017.03.2023EI 10 Fritz Paschke HS - UIW Lecture
Thu14:00 - 15:0020.04.2023EI 10 Fritz Paschke HS - UIW Lecture
Thu14:00 - 15:0027.04.2023EI 10 Fritz Paschke HS - UIW Lecture
Fri13:00 - 15:0016.06.2023EI 10 Fritz Paschke HS - UIW Lecture
Distributed Algorithms - Single appointments
DayDateTimeLocationDescription
Thu02.03.202311:00 - 13:00EI 10 Fritz Paschke HS - UIW Introduction
Fri03.03.202309:00 - 11:00EI 10 Fritz Paschke HS - UIW Lecture
Thu09.03.202313:00 - 15:00EI 10 Fritz Paschke HS - UIW Lecture
Fri10.03.202309:00 - 11:00EI 10 Fritz Paschke HS - UIW Lecture
Thu16.03.202313:00 - 15:00EI 10 Fritz Paschke HS - UIW Lecture
Fri17.03.202313:00 - 15:00EI 10 Fritz Paschke HS - UIW Lecture
Thu23.03.202313:00 - 15:00EI 10 Fritz Paschke HS - UIW Lecture
Fri24.03.202309:00 - 11:00EI 10 Fritz Paschke HS - UIW Lecture
Thu30.03.202313:00 - 15:00EI 10 Fritz Paschke HS - UIW Lecture
Fri31.03.202309:00 - 11:00EI 10 Fritz Paschke HS - UIW Lecture
Thu20.04.202314:00 - 15:00EI 10 Fritz Paschke HS - UIW Lecture
Fri21.04.202309:00 - 11:00EI 10 Fritz Paschke HS - UIW Lecture
Thu27.04.202314:00 - 15:00EI 10 Fritz Paschke HS - UIW Lecture
Fri28.04.202309:00 - 11:00EI 10 Fritz Paschke HS - UIW Lecture
Thu04.05.202313:00 - 15:00EI 10 Fritz Paschke HS - UIW Lecture
Fri05.05.202309:00 - 11:00EI 10 Fritz Paschke HS - UIW Lecture
Thu11.05.202313:00 - 15:00EI 10 Fritz Paschke HS - UIW Lecture
Fri12.05.202309:00 - 11:00EI 10 Fritz Paschke HS - UIW Lecture
Thu25.05.202313:00 - 15:00EI 10 Fritz Paschke HS - UIW Lecture
Fri26.05.202309:00 - 11:00EI 10 Fritz Paschke HS - UIW Lecture

## Examination modalities

Solution and presentation of homework assignments + reviewing (upload .pdf via myTI) + written tests + written exam.

## Course registration

Begin End Deregistration end
02.03.2023 08:00 12.03.2023 23:59

## Curricula

Study CodeObligationSemesterPrecon.Info
066 504 Master programme Embedded Systems Not specified
066 931 Logic and Computation Mandatory elective
066 932 Visual Computing Mandatory elective
066 937 Software Engineering & Internet Computing Mandatory elective
066 938 Computer Engineering Mandatory elective
860 GW Optional Courses - Technical Mathematics Not specified

## Literature

Textbook: Hagit Attiya, Jennifer Welch. Distributed Computing: Fundamentals, Simulations and Advanced Topics (2nd ed.), John Wiley and Sons, 2004. ISBN 0-471-45324-2

## Previous knowledge

Familiarity with the analysis of sequential algorithms and elementary discrete mathematics; reasonable skills in devising mathematical proofs. Some background in distributed systems and fault-tolerant systems is helpful but not required. Familiarity with the basics of scientific working (LaTeX, reviewing).

English