Kommunikationsnetze I Communication Networks I - uni-bremen.de · Kommunikationsnetze und Verkehrstheorie I + II Dienste und Protokolle, Lehrstuhl Kommunikationsnetze, Vorlesungsskript

www.comnets.uni-bremen.de INTRO - 1

Kommunikationsnetze : Systeme Communication Networks : Systems

Prof. Dr. Carmelita Görg Dr.-Ing Umar Toseef

Dr.-Ing. Koojana Kuladinithi Dr.-Ing Andreas Könsgen

Kommunikationsnetze

Communication Networks (ComNets) FB1/ITH/tzi – Universität Bremen

Raum S2260 0421 218 62365 -- Tel

0421 218 98 62365 -- Fax {cg|umr|koo|ajk}@comnets.uni-bremen.de


Contents (Inhaltsverzeichnis)

Distributed Systems (Verteilte Systeme) ISO/OSI Reference Model for Open System Interconnection

(Referenzmodell für offene Kommunikation) 7 Layer OSI Model (7 Schichten OSI-Modell) Formal Specification Methods for Protocols (Formale Spezifikationsverfahren für Protokolle) (SDL)


Contents (Inhaltsverzeichnis) (cont.)

(1) Physical Layer (Bitübertragungsschicht, Physikalische Schicht)

(2) Data Link Layer, Medium Access Control (Sicherungsschicht)

(3) Network Layer (Vermittlungsschicht) (4) Transport Layer (Transportschicht)

(5-7) Application Layers (Anwendungsorientierte Schichten) Local Area Networks (Lokale Netze)

Wide Area Networks (Weitverkehrsnetze) Network Control (Netzsteuerung):

(virtual) connections ((virtuelle) Verbindungen) Routing (Wegewahl)

Addressing (Adressierung)

Flow Control (Fluss-Steuerung)

System Examples (Systembeispiele):

ISDN/B-ISDN/ATM,TCP/IP


References

Martin Bossert, Markus Breitbach: Digitale Netze — Funktionsgruppen digitaler Netze und

Systembeispiele, B.G. Teubner 1999, ISBN 3-519-06191-0 Bernhard Walke: Kommunikationsnetze und Verkehrstheorie I + II Dienste und Protokolle, Lehrstuhl Kommunikationsnetze,

Vorlesungsskript RWTH Aachen

Jean Walrand: Communication Networks, A first course, WCB/McGraw-Hill 1998, ISBN 0-256-17404-0

Andrew S. Tanenbaum: Computer Networks, Prentice Hall 1996, ISBN 0-13 349945-6

Ross/Kurose, Computer Networking: A Top Down Approach, 4th ed., Addison-Wesley, July 2007 (slides available)

Internet: many references, some are given on our web pages

www.comnets.uni-bremen.de 5

Introductory remarks

PSTN (Public Switched Telephone Network) provides connectivity for more than a billion telephone sets

Phone network has changed: 1890: manual to automatic switching

After 1950: electro-mechanic to electronic switching

End 1980’s: analog to digital techniques

Beginning of the 1990’s: Digital Mobile

…

www.comnets.uni-bremen.de

6


Manual switching Cross bar switching



Last two decades: Computer communication is increasing very rapidly,

in the local and wide area Mobile communication is becoming

more popular, for both voice and data Today:

transition to VoIP, All – IP

Tomorrow ??? Future Internet Non-IP, Information Centric Networks Internet of Things Network Virtualization Cloud Computing (IaaS, PaaS, SaaS)


Subscribers….

Europe Germany US World

Inhabitants (2012)

739 Million 82 Million 314 Million 7 Billion

Fixed Telephones

Mobile Phones

Internet Users

INTRO - 8

Source: https://www.cia.gov/library/publications/the-world-factbook


Subscribers….

Europe Germany US World

Inhabitants (2012)


Fixed Telephones (2011)

226 Million 51.8 Million 146 Million 1.2 Billion

Mobile Phones (2011)


Internet Users (2009/10)

340 Million 65.1 Million 245 Million 2.1 Billion

Internet Hosts (2008)

- 22 Million 315 Million -

INTRO - 9

Source: https://www.cia.gov/library/publications/the-world-factbook


Research Communication Networks

Future Communication Networks

for mobile and dynamic systems

Heterogeneous Networks

Self-organizing Ad-hoc and Sensor Networks

Mobile Networks

Future Internet

INTRO - 10


Research

Fundamental Research

Industry Relevant Research

Application of Advanced Communication Technology

INTRO - 11


APPLICATIONS

INTRO - 12


SFB 637 – Transfer Project Intelligent Container

Food Transport Logistics

Surveillance during transport o Wireless Sensor Network

o Communication Service Module

1

3

2004 - 2013


MAN

User-Centered Network Planning and Optimization

Quality of Experience

Quality of Service

QoS

Experience Layer

Technical Layer QoS

QoS

QoE

QoE

QoE

QoS

LAN

QoE QoE

Objective: User-centered development of broadband communication networks including Quality of Experience

2012 - 2014


General Network Scenario

Eg: xDSL

Eg: 2G/3G/WLAN

Eg: Cable/

Optical Network

Eg: LTE/WiMAX

NuPEx

Capacity Demand

(Access Network)

Non 3GPP IP Access

INT

ER

NE

T

Ba

ck

bo

ne


xMOTION IST 5FP Project (June 2002 – January 2004)

lead by T-Systems, Germany (14 partners/6 countries)

three scenarios – thematically different – but similar in technical requirements and therefore architecture: • Emergency Management

• Teleambulance

• Transport Surveillance

Demonstrating: Usability of networks and the benefit for involved end-users;

Evaluating UMTS Testbed in Bremen from May 2003 on, extensive QoS measurements

ikom’s role:

Trial Leader Teleambulance

Communication Gateway

Expert Group Leader: Communication Networks, Mobile IP, Security

Technical Evaluation


Technologies and Applications in CoCar

Applications

- Hazard warning

- Floating car data

- Emergency brake light

- …

Cellular communication system

- UMTS, HSPA, LTE

- Multimedia Broadcast Multicast Service (MBMS)

- IP Multimedia Subsystem (IMS)

- XML Web Service Interfaces

Example use case


What is wearable computing?


Wearable Computing – „PDA in a Vest“

http://images.google.it/imgres?imgurl=http://www.ingineo.net/images/corporate/photofille1.jpg&imgrefurl=http://www.ingineo.net/cindex.php&h=454&w=359&sz=102&tbnid=mg7x0AeyhE8J:&tbnh=123&tbnw=97&start=4&prev=/images?q=wearable+computing&hl=it&lr=&sa=N


1. Firefighter (Paris Fire Brigade)

Increase the safety of the firefighters

Effective coordination and communication

Augmentation of human senses


2. Wearable Computing in Maintenance (EADS)

Inspection, Service and Repair

Smart Wearable Manuals

context sensitive, adaptive

Authoring, gather information during maintenance


3. The Clinical Pathway (Gespag)

Coordinate the medical staff on a ward

Access the controls of a medical device during examination

Present process related data to the physician

tzi show room


Universität Tübingen

Lehrstuhl für Rechnernetze und Internet

Selected Partners

24

http://www.alcatel-lucent.com/wps/portal/!ut/p/kcxml/04_Sj9SPykssy0xPLMnMz0vM0Y_QjzKLd4w3cjUDSUGYpvqRKGIG8Y4IEV-P_NxU_SB9b_0A_YLc0IhyR0dFAMzGbgw!/delta/base64xml/L3dJdyEvd0ZNQUFzQUMvNElVRS82X0FfMkU2


THE BEGINNING…


Distributed Systems (Verteilte Systeme)

Distributed System: Several independent computers

with in principle different operating systems

Connected through a network

Supporting one or more applications

Point-to-point connection between A and B.

A dedicated link can be used to connect two computers.

A B


Computer Engineering Objects

Thematic classification: Computer engineering can be divided in three categories, which are of the same relevance for distributed systems: 1. Computer Architecture

2. Data Comm. Systems Architecture

3. Application and Operating Software

Computer Architecture Structure

of comm. paths

Data Communication Systems Architecture

Operating Software, Compilers, Databases

Standard User Software

Operating System Kernel

Distributed Systems Apps &

Transport Protocols


Types of Distributed Systems Load sharing (Lastverbund ): uniform utilization of resources

by distributing the work load to different computers

Performance sharing (Leistungsverbund ): lower response times by distributing one task as subtasks to different computers

Communication sharing (Kommunikationsverbund ): transfer of data (messages) to different locations by installing, e.g., a mail service

Data sharing (Datenverbund): better utilization of disks, increased availability, increased safety

Maintenance sharing (Wartungsverbund ): faster and cheaper maintenance of different computers

Function sharing (Funktionsverbund ): making different functions available at different locations by allowing access to specialized servers (supercomputers, transputers, vector computers)


Communication Network (Kommunikationsnetz)

Definition: Technical infrastructure for information and communication systems with the following elements:

End devices, e.g., PC, work station, telephone, printer

Server for general tasks, e.g., data base server

Physical transmission media, e.g., cables

Network control (Netzsteuerung) and switching units (Vermittlungseinrichtungen), e.g., PABX Private Automated Branch Exchange (Nebenstellenanlage), Routers

Operating System Software, e.g., UNIX

Networking Protocol Software, e.g., TCP/IP

Application Software, e.g., ftp: file transfer protocol


Type of Networks

Private networks, internal networks (private Netze) Within one company or organization

Geographically confined, one location of a company

Global companywide networks (unternehmensweite Netze), corporate networks

Private branch exchange (Nebenstellenanlagen)

LAN: Local Area Networks (lokale Netze)

Public networks, external networks (öffentliche Netze) Public telephone network (Telefonnetz)

ISDN: Integrated Services Digital Network (Digitales Netz Integrierter Dienste)

Internet


Media (Medien)

Voice (Sprache)

Audio (Audio)

Text (Text)

Graphics (Graphik)

Data (Daten)

Video (Bewegtbilder)


Network Topologies (Netztopologien)


Network Topologies (Netztopologien)

Star (Stern) Ring Tree (Baum) Complete mesh, (vollständig vernetzt)

Bus

Satellite, Radio Cell

(Satellit, Funkzelle)


mailbag is unloaded from truck

empty mailbag

letter sorting machine

deliver and open letter

read letter

Translate from English to German

Presentation Layer

ideas for a description

Session Layer

write letter

Physical Layer

mailbag is transferred to plane

Data Link Layer

letter is put in mailbag

Transport Layer

put letter in envelope, address it and take it

to the post office

Network Layer

letter sorting

machine

Physical Layer

mailbag is unloaded from plane

Data Link Layer

empty mailbag

Anwendungsschicht

German engineer understands

patent

Präsentationsschicht

Sitzungsschicht

Physikalische Schicht

Sicherungsschicht

Transportschicht

Netzschicht


mailbag is transferred to truck

Sicherungsschicht

letter is put in mailbag

Network Layer

letter sorting machine

plane truck

Functionality of the OSI Layers

(Aufgaben der OSI-Schichten)

OSI: Open System Interconnection

ISO-Standard

Application Layer

American inventor has a patent


Postsack aus LKW ausladen

Postsack ausleeren

Briefsortieranlage

Brief zustellen

und öffnen

Lesen des

Briefes

Übersetzen vom Englischen ins

Deutsche

Presentation Layer

Überlegung einer

Beschreibung

Session Layer

Schreiben eines

Briefes

Physical Layer

Postsack in Flugzeug

verladen

Datalink Layer

Verpacken des Briefes in Postsack

Transport Layer

Brief verpacken, adressieren und

beim Postamt abg.

Network Layer

Briefsortier-

anlage

Physical Layer

Postsack aus Flugzeug

ausladen

Datalink Layer

Postsack ausleeren

Anwendungsschicht

Deutscher Ingenieur versteht

das Patent

Präsentationsschicht

Sitzungsschicht


Sicherungsschicht

Transportschicht

Netzschicht


Postsack in LKW verladen

Sicherungsschicht

Verpacken des Briefes in Postsack

Network Layer

Briefsortieranlage

Flugzeug LKW

Functionality of the OSI Layers

(Aufgaben der OSI-Schichten)

OSI: Open System Interconnection

ISO-Standard

Application Layer

Amerikanischer Erfinder hat

Patent


Functionality of OSI Layers

7 Application Layer (Anwendungsschicht)

6 Presentation Layer (Präsentationsschicht, Darstellungsschicht)

5 Session Layer (Sitzungsschicht)

4 Transport Layer (Transportschicht)

3 Network Layer (Vermittlungsschicht, Netzschicht)

2 Data Link Layer (Übermittlungsschicht, Sicherungsschicht)

1 Physical Layer (Bitübertragungsschicht, physikalische Schicht)


Services Primitives and Communication of Peer-to-Peer Entities (Dienstprimitive und Kommunikation von Peer-Entity zu Peer-Entity)

Entity Entity

Request Confirm Indication Response

Peer-to-Peer-

Communication Layer N

(Schicht N)

Layers 1 to (N-1)

(Schichten 1 bis (N-1))


Service Primitives Primitive Meaning

Request An entity wants the service to do some work

Indication An entity is informed about an event

Response An entity responds to an event

Confirm The response to an earlier request has come back


Example of a simple connection-oriented service with corresponding service primitives

1. CONNECT.request – Request a connection to be established

2. CONNECT.indication – Signal the called party

3. CONNECT.response – Used by the called party to accept/reject the call

4. CONNECT.confirm – Tell the caller whether the call was accepted

5. DATA.request – Request to send data

6. DATA.indication – Signal the arrival of data

7. DISCONNECT.request – Request that a connection be released

8. DISCONNECT.indication – signal the peer about the request


Analogy with the telephone system

1. CONNECT.request Dial Aunt Millie‘s phone number

2. CONNECT.indication Her phone rings

3. CONNECT.response She picks up the phone

4. CONNECT.confirm You hear the ringing stop

5. DATA.request You invite her for tea.

6. DATA.indication She hears your invitation

7. DATA.request She says she would be delighted to come …

8. DISCONNECT.request You hang up the phone

9. DISCONNECT.indication She hears it and hangs up too.


What are protocols ?

Networking software is organized as protocols Eg: Human protocol vs network protocol:

Hi

Hi

When are you ready ?

2:00

TCP connection req.

TCP connection reply.

Get http://www.rpi.edu/index.htm

<file>

time

http://www.ecse.rpi.edu/Homepages/shivkuma/teaching/video_index.html#ccn_foils


Protocol (Protokoll) Protocol (Protokoll) a formal description of i) message formats (PDU: Protocol Data Units, Protokoll-

Dateneinheiten) ii) and the rules

which two or more machines must follow to exchange those messages

e.g.: TCP: Transport Control Protocol, IP: Internet Protocol Protocols usually exist in two forms:

1. In a textual form for humans to understand. E.g. the majority of Internet protocols are distributed as RFCs

(Request for Comments), which can (and should) be read to understand the protocols' design and operation.

2. As formal descriptions or programming code for computers to understand.

Both forms should ultimately specify the precise interpretation of every bit of every message exchanged across a network.


Protocol Description

Protocols can be described by extended finite state machines (erweiterte endliche Automaten)

with state changes depending on variables, e.g., time dependent. Every state (Zustand) can be described by a set of variables.

by a formal specification language, e.g., SDL (Specification and Description Language)

Protocol description contains Syntax: defines syntactical units, e.g., sequence of characters Semantics (Semantik): describes the meaning and usage of

syntactically correct constructs Pragmatics (Pragmatik): information and knowledge about the

effects of actions Timing requirements (Zeitvorgaben): e.g., timeouts,

are a main part of protocols to guarantee the synchronization of the communicating protocol state machines, e.g., after transmission errors



Protocol Implementations Protocol objects are building blocks of a network architecture

Each protocol object has two different interfaces

service interface: defines operations on this protocol

peer-to-peer interface: defines messages exchanged with peer

service interface

peer interface

Li+1 Li+1

Li Li

service interface


Interface (Schnittstelle)

Interface (Schnittstelle)

describes signals (Signale), signal combinations (Signalkombinationen), and timing requirements (Zeitgesetze) that enter and leave a protocol executing entity.

Examples: V.24, serial interface (serielle Schnittstelle),

MMI: Man Machine Interface (Mensch-Maschine-Schnittstelle)

Protocols and interfaces always exist together.


Standardization

(Standardisierung)

WRC World

Radiocommunication

Conference

ITU-R

CCIR Comitée Consultatif

International

Radio

ITU-T

CCITT Comitée Consultatif

International des

Télegrafes et Télephones

IRFB International

Frequency

Registration Board

CISPR Comitée International

Special Perturbance

Radio

ISO International

Standardisation

Organisation

IEC International

Electrotechnical

Commission

ITU International

Telecommunications

Union (1866)

UN United Nations


Standardization in Europe

(Standardisierung in Europa)

CEC Commission of the

European Communities

ITSTC Information Technology

Steering Committee

CEPT Conference of European

Postal and Telecommun.

Administrations

CEN Comitée Européen

de Normalisation

CENELEC Comitée Européen de

Normalisation

Electrotechnique

ETSI European Telecommun.

Standards Institute

GSM DECT M2M UMTS


Internet Standards

IAB Internet Architecture

Board

IETF Internet Engineering

Task Force

IRTF Internet Research

Task Force

APP Routing Transport Security

HTTP .. MPTCP ..

ICNRG ..


Image Source: http://6lowpan.net/the-book/

IPSO: IP for Smart Object

OGC: Open Geospatial Consortium

ETSI: European Telecommunications Standards Institute

ISA: Industrial Standardisation for Automation

IETF: Internet Engineering Task Force

CORE: Constrained RESTful Environments

ROLL: Routing Over Low power Lossy networks

6LOWPAN: IPv6 over Lower power Wireless PAN

Standards for Internet of Things

Documents

Kommunikationsnetze I Communication Networks I - uni-bremen.de · Kommunikationsnetze und Verkehrstheorie I + II Dienste und Protokolle, Lehrstuhl Kommunikationsnetze, Vorlesungsskript