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Infokommunikációs rendszerekInfocom Systems

5. Nyilvános távbeszélő (PSTN) hálózatok,

gerinchálózatokTelephone networks(PSTN), backbone networks

Takács György

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The 3 lessons in network studies

• Public Switched Telephone Networks (PSTN), Integrated Service Digital Networks (ISDN), backbone networks

• Mobile Networks -- Public Land Mobile Networks (PLMN) GSM, UMTS, DECT, TETRA, Bluetooth, Globalstar, Iridium

• Private networks, Broadcasting networks, Cable TV networks (CaTV)

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Gyorsjelentés 2013. augusztus

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Special features of networks

• Only services can be sold on the real market!

• There are not electronic communication services without networks.

• You could not buy networks. You have to plan, to construct, to operate, to develope according to the actual demands and to eliminate at the and of service provision.

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Basics of network components

• Backbone networks: long distances, high traffic, interconnection of nodes, transport bits of any services, high relability.

• Access networks: local distances, interconnection of terminals and local nodes

• Network planning: selecting topology, optimal selection of positions of nodes, dimensioning of node traffic handling capacities, dimensioning of link capacities, selecting technologies.

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AOL USA BACKBONE

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Public Switched Telephone Networks (PSTN)

• Brief history

• Basics

• Network structures

• Network implementation

• Network development trends

• Missing topics

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Brief history I.• 1876 A. G. Bell Patent of telephone (50.000 phone within

3 years)• 1877 T. A. Edison patent of carbon microphone (covering

long distances)• 1878 Puskás Tivadar the first telephone exchange in

Connecticut• 1881 Puskás Ferenc the first telephone exchange in

Budapest• 1890 The first Wien-Budapest international telephone

connection• 1892 The first automatic telephone exchange in Indiana• 1928 The first automatic telephone exchange in Budapest• 1997 The last manual exchange moved to museum in

Hungary

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Brief history II.

• The technical level of Hungarian PSTN networks are very high due to the fast development from 1992-2002

• From 1 million subscriber to 10 million one

• From 1000 manual exchange to almost fully digital network

• COCOM list restriction not from our side!!!

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Basics of telephony• 2/4 wire for voice

• Feeding of circuit

• Access solutions

• Backbone

• Signalling basics for a telephone call

• Source of revenues

• ADSL principles

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2/4 wire for voice

2 wire simplex

2 wire duplex4 wire simplex

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Electronic hybrid circuit

ZT

Zg r r

Twisted pair cable

Z0 characteristic impedance

ZT ~Z0

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Powering of telephone sets

Feeding bridge

Subscriber line Local exchange

Traditional feeding bridge circuit

DC line current: 20….60 mA

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Access solutions

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Connections to the local exchange

Distribution cables

Drop cables,Indoor cables

Main cables

Distribution cabinets

Distribution boxes

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Access network implementation

Exchange

Main Distribution Frame (MDF)

DPPrimary Cross Connexion

Point (PCP)

Secondary Cross Connexion

Point (SCP)

DPDistribution Point (DP)

Cable

Overhead

DP

DPMain Cable

Distribution Cables

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Cable duct system implementation

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Cable distribution cabinet (street version) implementation

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Signalling basics for a telephone call

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Channel-associated signalling for a trunk call

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Common-channel signalling for a trunk call

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Backbone issues in a small country with dense population

• Fully optical – only spare radio connections• Covered distance between nodes max 100 km• In Hungary the telecom traffic concentrated in

Budapest and towards Budapest (like the road traffic)

• Concentration of switching capacities in higher level nodes

• Fault tolerant topology is required for reliable services

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Network structures

• Basics

• MATÁV structures

• PANTEL structures

• Interconnection issues

• Structure and numbering

• Intelligent Network Concept

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Basic structures in PSTN/ISDN networks

• Star topology

• Multipolar topology

• Meshed topology

• Ring topology

• Bus topology

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STAR BUS

RING

MESHED

MULTIPOLAR

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MATÁV NETWORK STRUCTURE

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Telephone network structure of MATAV

Secondary exchange

Primary exchange

Backbone network

Localexchange

Subscriber

Accessnetwork

Interexchangenetwork

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Felső sík csomópontja

Alsó sík csomópontja

622 Mbps

2.4 Gbps

P KI T ávközlésfe jlesztés iIn téze t

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DIGITÁ LIS GERIN CHÁLÓZATSDH hálózati struktúra 2000.

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P KI T ávközlésfe jlesztés iIn téze t

H á lóza tfe jlesztés i ágaza t

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622 M bps

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G yűrű azonosítóR 1

B UD APESTI Á TK ÉR ŐH ÁLÓZATH álózati struktúra 2000.

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1. Layer

Physical layer

Optical cable

2. Layer

Data link layer

IP link

3. Layer

Network layer

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PANTEL optical backbone structures

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PANTEL logical SDH rings

Ring #4(18 nodes)

Ring #2(5 nodes)

Not closed!!

Ring #5(8 nodes)

Simplified structure of PanTelSDH backbone network

Ring #1 (19 nodes)

Ring #3(12 nodes)

MAN (11 nodes)

(Bp. total: 18 nodes)

Ring #4/b(2 nodes)

Total numberof nodes : 75

2*STM-1to PTA

2*STM-1 toSlovakia

STM-4 toUTA

August 2000

Sopron

HhalomCsorna

(Issue: 18. August 2000, Laszlo Zorkoczy)

These STM's includeleased lines to Frankfurt,

Amsterdam and Praha

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Interconnection principles

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Interconnection principles

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Interconnection implementation

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Network structure and numbering

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Network implementation

• Access issues: Rural, City, Down-town, areas, In-door cabling, Underground copper cables, Overhead cables, ADSL, Fibre To the Curb (FTC), distribution frames

• Core issues: Underground fibres, overhead fibres,

• Switching and multiplexing position of nodes• Traffic issues: dimensioning of switches and

links

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Access network implementation

Exchange

Main Distribution Frame (MDF)

DPPrimary Cross Connexion

Point (PCP)

Secondary Cross Connexion

Point (SCP)

DPDistribution Point (DP)

Cable

Overhead

DP

DPMain Cable

Distribution Cables

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Costs and revenuesThe revenues are monthly fees and traffic

based fees

Traffic density (Erlang/km2

Network costs

Wireline networks

Cellular networks

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Telephone bill balance

balance

timePre-paid

balance

time

balancetime

Post-paid

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ADSL principles

• ADSL =Asymmetric Digital Subscriber Line• Download max 8Mbit/s (usually 1,5 Mbit/s)• Uplink 64-256 kbps• Max covered distance 3,6 km• ITU-T G.992.x standards• The frequency band separated in 3 parts: PSTN/ISDN,

uplink, downlink• Data links 4,3125 kHz channels• Discrete Multi Tone (DMT) coding, 256 channels• 1-5 channels for PSTN/ISDN• 32 channels for uplink• 218 channels for downlink

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ADSL principles

PSTN/ISDN UPLINK DOWNLINK

Carrier frequencies

Time frames: one octett in each frequency

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ADSL principles

To ISPs

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Missing topics

• Telephone sets, terminal equipment (Lecture in Nov )

• Services (Lecture in Nov )• Regulation issues (Lecture in November )• Details of ADSL• NGN (Next Generation Networks in December)• Network planning (optional subject in semester

7.)

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Traditional Solutions in

Services

Access Transport & Switching Networks

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Services/Applications

Connectivity

Future Solutions

Network development trends

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