S-72.1130 Telecommunication Systems Overview. HUT Comms. Lab, Timo O. Korhonen 2 Practicalities...

S-72.1130 Telecommunication Systems

Overview

HUT Comms. Lab, Timo O. Korhonen

2

Practicalities Lecturers: Timo Korhonen (09 451 2351), Michael Hall (09 451

2322) Tutorials: Mika Nupponen (09 451 5416), Naser Tarhuni (09 451

2362) Exam: Monday, 17.12.2007, 9 - 12 No need to buy any books, however, following references can be

useful: James F. Kurose, Keith W. Ross: Computer Networking, 2nd ed. A. Leon-Garcia, I. Widjaja: Communication Networks, 2nd ed. M. Duck, R. Read: Data Communications and Computer

Networks, 2nd ed. W. Stallings: Data and Computer Communications, 7th ed. (Ericsson, Telia: Understanding Telecommunications, Part I &

Part II) Grading: Closed book exam and voluntary tutorials:

Round[ e (5 p) +t (5p) *0.15] Lecture handouts:

http://www.comlab.hut.fi/studies/1130/lectures2007.htm

Homepage: http://www.comlab.hut.fi/studies/1130 Course feedback: http://palaute.ee.hut.fi/


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Lectures and tutorials

Lectures: 21.11 Overview to Telecommunication Systems 28.11 Public Switched Telephone Network 29.11 Transport and Signaling in the PSTN 5.12 Intelligent Network and Mobile Networks 12.12 Wireless Local Area Networks 13.12 Internet

Tutorials: First tutorial session will be on 29.11.2007, 12-14,

S1 A self-study tutorial to be returned 17.12.2007 Check all tutorial info at:

http://www.comlab.hut.fi/studies/1130/Exercises/


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Course Topics

Public Switched Telephone Network (PSTN) Integrate Services Digital Network (ISDN) and SS7 Wireless Local Area Networks (WLANs) The Internet, for instance…

TCP/IP (Transmission Control Protocol/internet protocol) Suite

UDP (User Datagram Protocol in transport layer)

SIP (Session Initiation Protocol in application layer)

QoS: MPLS (Multiprotocol Label Switching), Differentiated Services

Services Telecommunications market


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Networking Subtopics User services as

IN services: call last dialed, alternate billing services (as calling card, collect call)

Internet: web, email, ftp … Terminals modems and PSTN/ISDN phones, user interfaces… Routing and switching unicast - multicast, devices &

protocols (RSVP) Transmission and links (fibre, coax-cable..) Access and transport techniques (flow control, error control) Signaling (SS7, X.25, Frame relay ...) Network management (as OMAP of SS7...) Interworking (gateways, bridges ...) Network planning Standards and

recommendations: ITU-T, ITU-R, IETF, IEEE,...

IN: Intelligent NetworkIETF: Internet Engineering Task ForceIEEE: the Institute of Electrical and Electronics Engineers, IncRSVP: Resource ReSerVation ProtocolITU: International Telecommunications UnionSS7: Signaling System 7 (in ISDN)OMAP: Operation and Maintenance Application Part

IN: Intelligent NetworkIETF: Internet Engineering Task ForceIEEE: the Institute of Electrical and Electronics Engineers, IncRSVP: Resource ReSerVation ProtocolITU: International Telecommunications UnionSS7: Signaling System 7 (in ISDN)OMAP: Operation and Maintenance Application Part


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Course Objectives

Course discusses structure and properties of telecommunications networks

Network topologies Protocols Interfaces Physical realizations

Role of abbreviations – understanding concepts Abbreviations refer (define) concepts Abbreviations describe standardized protocols &

parts of telecommunication systems More important to understand the meaning of

concept than to remember the words building up abbreviations


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History

18001850

1850

1900

1900

1950

1950

2000

Volta:batteries; Fourier, Laplace, Cauchy: MathematicsAmpere, Faraday, Henry: Basic electronics

1826 Ohm’s law

Morse, Kelvin:Early telegraphy

1844 Steinheil’s commercial telegraphy

Bell, Edison: TelephonyHeaviside, Pupin, Campbell: Theory of T.

1887 Strowger’s automated switch1864 Maxwell’s electrodynamics

1897 Marconi’s wireless telegraphy

Lee De Forrest: Triode-tube;Transcontinental telephone.Communication’s electronic

1918 Armstrong’s heterodyne radio

1998 Digital TVlaunched in USA

Internet,Wide spread digital signal processing

1969 ARPANET

Commercial dataservices: DSP, channel coding

1972 Motorola’s cellular system

1950 TDMA telephony1937 Alec Reeves’ PCM

trans-Pacific,trans-Atlanticoptical cables


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Information Society

“Information and Communication Anytime, Anywhere, and in Any Form”

Key development fieldsforming the business case:

To understand how networks/terminals/services evolve consider especially services because all network costs are paid by service users:

Services shape telecommunications’ evolution and effect greatly on which technology is chosen!

Services shape telecommunications’ evolution and effect greatly on which technology is chosen!

Services GlobalMarket

Technology

Legislation/Regulation/Standardization


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Paradigm ShiftOld view

(circuit switched PSTN)

Current view (packet switched Internet)

Speech Low-rate data modems (V.90)

+ Other computers &agent-programs (M2M) SMS MMS

VoIPDVB-H

smtpftphttp


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Components of Telecommunication Networks

Core and access sub-network Access part terminated by terminals Network nodes and links are optimized for certain assumed traffic

(source statistics) and transmission channels (transfer function and noise)

This model of telecommunication networks applies both to data and voice networks (packet and circuit switching)

Node 1 Node 2

Node 3

Access

Core Network

TerminalsTerminals

Access

Internal structure can follow differenttopologies: mesh/star/bus/ring (see also supplementary material)


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Network Topology Different topologies in

different networks BUS - Ethernet Ring - FDDI Mesh - Internet;

Number of connections required:

N: number of nodes Selection of topology

effects for instance applicable MAC scheme & network reliability

Optical networks

2( 1)

2 2

N N N

Optical star-coupler

Example: FDDI: Token ring, Ethernet: CSMA/CD (an IEEE 802 technology)


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Tasks of a Telecommunication System

Initialization and release of link/across network Synchronization RX & TX - carriers, start and end of

frames/packets Information exchange protocols determine protocols for

communication in entities: CSMA, CDMA, … TCP/IP Error control - corrective measures Addressing and routing Message formatting, source coding Therefore, networks realized by following a layered structure

(as Open System Interconnections (OSI) or TCP/IP stack ) NOTE: “Entities” refer to network elements as routers and

bridges or different OSI-layers

Entity 3Entity 3

Entity 2Entity 2

Entity 1Entity 1

Entity 3Entity 3

Entity 2Entity 2

Entity 1Entity 1interface

Physical connection

Input Output


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Example: Routers, hubs and bridges

Router is a device that extracts the destination of a packet it receives, selects the best path to that destination, and forwards data packets to the next device along this path.They connect networks together; a LAN to a WAN for example (link layer).

Hub (for instance Ethernet hub, USB hub) A device that allows many USB devices to be

connected to a single USB port Ethernet hub = multi-port repeater

(concentrator) Works in physical level

Network bridge connects multiple network segments at the data link layer

Ref: Wikipedia


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Nodes, links & layers with well-defined (standardized) interfaces Network is optimized for certain, assumed traffic Earlier Voice and data services in PSTN or data in dedicated

networks (X.25/Frame Relay) Nowadays Internet carries both data and voice - QoS important!

Development of Data and Voice Networks

Frame Relay:- applies virtual circuits- example to connect LANs- for high quality (links have modest error correction & flow control)- rates: 2-50 Mb/sFrame Flow Control:(HDLC*) - service for a pair of communicating entities- reassures non-over- whelming communications (packets could suffocate receiver )

Voice/modems in PSTN

Leased lines

Earl

ier

Sce

nari

os

*High-Level Data Link Control


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CurrentScenario

Modified from W. Stallings: Data and Computer Communications, 7th ed(home site lecture slides)

MPLS

WLANRouter

BluetoothDevice

ISDN, V.90,Cable modem,ADSL etc.

FireWireDevice

*Synchronous Optical Networking

*


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Telecommunications Market

Telecommunication network content and technology producers, operators and consumers form an interoperable hierarchy

End-Users

Content and Service Providers

Service operators/Telecommunications Networking Solutions

Physical Telecommunication Network


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Telecomm Market Players End-users (individuals , companies, machine-to-

machine communications) Information service providers (Telephone catalog

services designed by a company, giving telephone numbers when you give a name or an address… Eniro)

Service brokers sell dedicated service packages (...MySAP)

Network operators (...Elisa, Telia, or Radiolinja) Content providers (...Paramount Pictures)


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Evolving Telecommunication Services

PSTN-originated services

2G Services 2.5G-3G Services

Voice Mail

Call Holding/Call Waiting

Call Barring/Call Forwarding

Basic VoiceBW ~ 4 kHz

Pre-paid Services

InternationalRoaming

Data: 9.6 Kb/s … 380 kb/s

WAP

13 Kb/s Voice

Catalog EnquiryInternet Access

Mobile Commerce

Instant Messaging/Chat

Push-adds

Streaming: Video, Audio

Data up to 2 Mb

Interactive Games

Rich Call: “See what I see!”

MMS

Location Identification - Presence

All-IP: Location, mobility management, presence,personalization, security

Circuit/Packet Switching: Mobility, Data communication

Circuit Switching:Voice services,IN-services, limited data

SMS

Data: 56 kb/s (V.90)

Push-toTalk

III Play*

10 Mb/s (HSDPA)

*III Play=VoIP+DVB-H+Internet


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Speech and Data Communications

Teletraffic can be forced to fixed rate or bandwidth as speech in PSTN or in ATM traffic

Waste of network resources follows if network resources can not be reallocated on request (=statistical multiplexing)

SpeechSpeech DataData

DelaysDelays

ErrorsErrors

Limited to ~200 ms Depends on service

High tolerance Very limited tolerance

StreamStreamContinuous: Circuit

switching Bursty: Packet

switching


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Different Services Require Different Transmission Rates

10k 1M 100M

Streaming with MPEG, MP3Streaming with MPEG, MP3FaxFax

Inter-LAN/PBX communicationsInter-LAN/PBX communications

VideoVideo

TV/HDTVTV/HDTVVideo conferencingVideo conferencing

BroadcastingBroadcasting

TelephonyTelephony

Data

Vid

eo

Voic

e

Bit rate (b/s)

Maximum Rates of someTransmission Technologies

GSM 14.4 kb/sHSCSD 56 kb/sPOTS 56 kb/sGPRS 114 kb/sEDGE 384 kb/sFrame Relay 1.54 Mb/sT-1 1.54 Mb/sADSL 8 Mb/sCable modems 52 Mb/sEthernet 10 M, 100 M, 1GFDDI 100 Mb/s OC-256 13.3 Gb/s

Maximum Rates of someTransmission Technologies

GSM 14.4 kb/sHSCSD 56 kb/sPOTS 56 kb/sGPRS 114 kb/sEDGE 384 kb/sFrame Relay 1.54 Mb/sT-1 1.54 Mb/sADSL 8 Mb/sCable modems 52 Mb/sEthernet 10 M, 100 M, 1GFDDI 100 Mb/s OC-256 13.3 Gb/s


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1 Physical LayerElectrical signals and cabling

3 Network LayerRoutes data to differentLANs and WANs based onnetwork address

4 Transport LayerEnsures delivery of entire fileor message

5 Session LayerStarts, stops sessionmaintains order

6 Presentation LayerEncryption, data conversion:ASCII to EBCDIC, BCD to binary ...

BCD: Binary Coded Decimal(four bits present each decimal digit)EBCDIC - Extended Binary Coded Decimal Interchange Code (256 characters by 8 bits)

7 Application LayerType of communications:E-mail, file transfer, client/server

TCP/IP Suite works with 5 layers only

RTP: Real-time Transport Protocol (for internet telephony applications)ICMP: Internet Control Message Protocol (errors/IP package processing)ARP: Address Resolution Protocol (data link address determination)RARP: Reverse ARP (for instance DHCP host can ask its IP address)

2 Data Link (MAC) LayerTransmits packets form node to nodebased on station address

OSI La

yers


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Each OSI-layer has its Standardized Services

IEEE 802.X, HDLC, ANSI X3T9.5, SMT,...

V.24, V.35, V.90, 10Base5, 10Base2, 10BaseT, FDDI, SDH, G.703...

ACSE, ROSE, RTSE, ...

NCP, FTP, Telnet, SMTP, SNMP, LAT, AFP, SMB...7. Application

6. Presentation

5. Session

4. Transport

3. Network

2. Data Link

1. Physical

NetBIOS, NetBEUI, DNS, ...

SPX, PEP, TCP, UDP, NSP...

IPX, RIP, SAP, IDP, IP, ARP, RSVP, ICMP, X.25, RIP...

Understanding abbreviations: Wikipedia or Mpirical (http://www.mpirical.com/companion/mpirical_companion.html)


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The user clicks on a link to indicate which document is to be retrieved. The browser must determine the Internet address of the machine that contains the document. To do so, the browser sends a query to its local name server. DNS, UDP, HTTP, FTP, HTMLOnce the address is known, the browser establishes a connection to the server process in the specified machine, usually a TCP connection. For the connection to be successful, the specified machine must be ready to accept TCP connections. TCP/IP

The browser runs a client version of HTTP, which issues a request specifying both the name of the document and the possible document formats it can handle.

The machine that contains the requested document runs a server version of HTTP. It reacts to the HTTP request by sending an HTTP response which contains the desired document in the appropriate format. Document sent to the receiver.

The user may start to view the document. The TCP connection is closed after a certain timeout period.

1.

2.

3.

4. – 6.

7. – 8.

Step:

Protocols in Practice: Retrieving a Document from the Web

From Leon-Garzia, Widjaja: Communication Networks, 2th ed., Instructor’s Slide Set

Addressing

TCP/IP connection

Document specifications

Document response

Viewing the document,closing TCP/IP


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ITU-T Standards (www.itu.int)

G - Transmission Systems and media, digital systems and networks

H - Audiovisual and multimedia systems I - ISDN Q - Switching and signalling V - Data communications over PSTN X- Data networks and open system

communicationsOther important standardization organizations:- IEEE (Institute of Electrical and Electronics Engineers)- IETF (The Internet Engineering Task Force)- ISO (International Organization for Standardization)- ETSI (European Telecommunications Standards Institute)

Note that ITU-T standards nowadays available free-of-charge at ITU-T site


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Future Perspectives - PLMN

Modest-rate Internet

Portable, global virtual reality

1995 2010

19921992

2G: Fax/data/SMS9.6 kb/s

19981998

2G: Data compr.2.5x9.6 kb/s

20002000

2.5G:HSCSD28.8 kb/s

20012001

2.5G:GPRS92 kb/s

20032003

2.5G:EDGE384 kb/s

20042004

3G:UMTS2 Mb/s

2005-2005-

3G:HSDPA10 Mb/s

Single system support

Multi-system support TerminalsTerminals

GSM, DECTUMTS/4GWLANsWiMAX

Radiointerfaces

Radiointerfaces

PSTN, ISDN TCP-IP/UDP ATM, ISDN,B-ISDN

Trunk/Core

Trunk/Core

Voice, low rate data ServicesServices

Softwareradio

Multimedia,Virtual reality

Push-to-talk, VoIP

GPRS, EDGE, HSCSD, HSDPA


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Future Perspectives PLMNs and especially wireless LANs develop very

fast in home & office networks Increasing data rates QoS very important Traffic gets more symmetrical (P2P) PSTN:

Used to transfer more and more data traffic Voice services of PSTN use IP (VoIP) and move

to Internet Need of seamless communication of NGN means

that different networks must link efficiently -> Inter(net)working between different kind of networks important (example: Bluetooth-WLAN-UMTS)

PLMN: Public Land Mobile Network, IP:Internet Protocol SLIP: Serial line IP


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Future Perspectives – Special Topics Sensor networking

Autonomous, self-organizing Low power consumption Flexible topology High number of intelligent nodes Complex MAC-protocols

Usage of sensor networks Monitoring Body area networks (BANs)

Cross-layer design Wire-replacement technologies

Bluetooth Zigbee FireWire


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Web Resources Tutorials, links, abbreviations :

http://searchnetworking.techtarget.com/ Mpirical bank of abbreviations: http://www.mpirical.com/

companion/mpirical_companion.html Wikipedia: http://en.wikipedia.org Note: Many standards available online in the Library (as

for instance ITU-standards ) Have a look on course reference books homepages! 3:rd generation PLMN: www.w3.org, www.3gpp.org Finish Spectral Regulation: www.ficora.fi IEEE standards: www.ieee.org ITU standards: www.iti.org xDSL development: www.adsl.com


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Review Questions

What does the concept of information society means? Describe implications to technology/service development.

What are the basic components and tasks of generalized telecommunication network?

Give an example how telecommunication services have evolved? What were the enabling changes in technology?

What are the OSI layers? Give examples of their tasks.

Summarize the expected development of mobile telecommunication networks in terminals, radio interface core network and in services

S-72.1130 Telecommunication Systems - Annex

What is …(Some important concepts)


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What is Ethernet?

Ethernet is the most widely-installed local area network (LAN) technology. Specified in a standard, IEEE 802.3, Ethernet was originally developed by Xerox and then developed further by Xerox, DEC, and Intel. An Ethernet LAN typically uses coaxial cable or special grades of twisted pair wires. Ethernet is also used in wireless LANs. The most commonly installed Ethernet systems are called 10BASE-T (100 m / CAT 3 cables) and provide transmission speeds up to 10 Mbps. Devices are connected to the cable and compete for access using a Carrier Sense Multiple Access with Collision Detection (CSMA/CD) protocol.

Fast Ethernet or 100BASE-T provides transmission speeds up to 100 megabits per second and is typically used for LAN backbone systems, supporting workstations with 10BASE-T cards. Gigabit Ethernet provides an even higher level of backbone support at 1000 megabits per second (1 gigabit or 1 billion bits per second). 10-Gigabit Ethernet provides up to 10 billion bits per second.

Source: Searchnetworking.com


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What is FDDI?FDDI (Fiber Distributed Data Interface) is a set of ANSI and ISO standards for data transmission on fiber optic lines in a local area network (LAN) that can extend in range up to 200 km (124 miles). The FDDI protocol is based on the token ring protocol. In addition to being large geographically, an FDDI local area network can support thousands of users. FDDI is frequently used on the backbone for a wide area network (WAN).

An FDDI network contains two token rings, one for possible backup in case the primary ring fails. The primary ring offers up to 100 Mbps capacity. If the secondary ring is not needed for backup, it can also carry data, extending capacity to 200 Mbps. The single ring can extend the maximum distance; a dual ring can extend 100 km (62 miles).

FDDI is a product of American National Standards Committee X3-T9 and conforms to the Open Systems Interconnection (OSI) model of functional layering. It can be used to interconnect LANs using other protocols. FDDI-II is a version of FDDI that adds the capability to add circuit-switched service to the network so that voice signals can also be handled. Work is underway to connect FDDI networks to the developing Synchronous Optical Network (SONET).



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Multiprotocol Label Switching (MPLS)

Multiprotocol Label Switching is a standards-approved technology (IETF: RFC 3031) for speeding up network traffic flow and making it easier to manage. MPLS involves setting up a specific path for a given sequence of packets, identified by a label put in each packet, thus saving the time needed for a router to look up the address to the next node to forward the packet to. MPLS is called multi-protocol because it works with the Internet Protocol (IP), Asynchronous Transport Mode (ATM), and frame relay network protocols. With reference to the standard model for a network (the Open Systems Interconnection, or OSI model), MPLS allows most packets to be forwarded at the layer 2(switching) level rather than at the layer 3(routing) level. In addition to moving traffic faster overall, MPLS makes it easy to manage a network for quality of service (QoS). Note: ATM header overhead always at least 10 %, for MPLS it is order of magnitude smaller.



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Streaming Technologies

Major streaming video and streaming media technologies include RealSystem G2 from RealNetwork, Microsoft Windows Media Technologies (including its NetShow Services and Theater Server), and VDO. Microsoft's approach uses the standard MPEG compression algorithm for video. The other approaches use proprietary algorithms. (The program that does the compression and decompression is sometimes called the codec.) Microsoft's technology offers streaming audio at up to 96 Kbps and streaming video at up to 8 Mbps (for the NetShow Theater Server). However, for most Web users, the streaming video will be limited to the data rates of the connection (for example, up to 128 Kbps with an ISDN connection). Microsoft's streaming media files follow Advanced Streaming Format (ASF).



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Security and Secrecy* Services require security & secrecy, e. g. reliable,

shielded transfer (Example WEP of Wi-Fi). Especially important for

NGN-services that are ‘near to users’ Vulnerable services:

medical/health as tele-surgery rescue, police, defense

Networks can provide this in several network levels (problem: overheads);

fixed lines (PSTN, frame relay) flexible routing (SS7) scrambling or encryption (PLMNs) coding or ciphering (in all modern telecom links &

nets) Often used concept: AAA: Authentication, Authorization,

Accounting• Message goes to the right receiver • Others can’t do eavesdropping *


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What is AAA?Short for authentication, authorization and accounting, a system in IP-based networking to control what computer resources users have access to and to keep track of the activity of users over a network.

Authentication is the process of identifying an individual, usually based on a username and password. Authentication is based on the idea that each individual user will have unique information that sets him or her apart from other users.

Authorization is the process of granting or denying a user access to network resources once the user has been authenticated through the username and password. The amount of information and the amount of services the user has access to depend on the user's authorization level.

Accounting is the process of keeping track of a user's activity while accessing the network resources, including the amount of time spent in the network, the services accessed while there and the amount of data transferred during the session. Accounting data is used for trend analysis, capacity planning, billing, auditing and cost allocation.

AAA services often require a server that is dedicated to providing the three services. RADIUS is an example of an AAA service.

Source: www.webopedia.com


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What is Bluetooth?

Bluetooth is an industrial specification for wireless personal area networks (PANs).

Bluetooth provides a way to connect and exchange information between devices like personal digital assistants (PDAs), mobile phones, laptops, PCs, printers and digital cameras via a secure, low-cost, globally available ISM short range radio frequency.

Bluetooth lets these devices talk to each other when they come in range, even if they are not in the same room, as long as they are within up to 100 metres (328 feet) of each other, dependent on the power class of the product. Products are available in one of three power classes:

Class 3 (1 mW) is the rarest and allows transmission of 10 centimetres (3.9 inches), with a maximum of 1 metre (3.2 feet)

Class 2 (2.5 mW) is most common and allows a quoted transmission distance of 10 metres (32 ft)

Class 1 (100 mW) has the longest range at up to 100 metres.

The specification was first developed by Ericsson, and was later formalized by the Bluetooth Special Interest Group (SIG). SIG was established by Sony Ericsson, IBM, Intel, Toshiba and Nokia, and later joined by many other companies as Associate or Adopter members. Bluetooth is also IEEE 802.15.1 that specifies its radio interface by using frequency hopping.

http://en.wikipedia.org/wiki/Bluetooth


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Quality of Service (QoS)

ATM, MPLS and UMTS support wide range of services that posses different quality of service (QoS) requirements.

Transportation system differentiated into constant rate, real-time and higher-latency services by Multi-Protocol Label Switching (MPLS) or Differentiated Services (DiffServ)

User services can be divided to different groups, depending on QoS requirements. Four traffic classes can been identified for ATM:

Conversational class (very delay-sensitive traffic) Streaming class Interactive class Background class (the most delay insensitive)

Hence TCP (Connection-oriented transport-layer) is not a good choice if errors can be tolerated

UDP (Connectionless transport-layer protocol) appropriate for many streaming applications (error control in upper layers)


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Example from mpirical - database

http://www.mpirical.com/companion/mpirical_companion.html

S-72.1130 Telecommunication Systems Overview. HUT Comms. Lab, Timo O. Korhonen 2 Practicalities...

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