Overview of Pstn Spstove002[1]
description
Transcript of Overview of Pstn Spstove002[1]
-
CETTM MTNL
1Overview of PSTN
OVERVIEW OF PSTN
MODULE ID: SPSTOVE002
-
CETTM MTNL
2Overview of PSTN
Topics
Public Switched Network
Hierarchy of Switches
PSTN N/W and Components
Long Distance (Toll) Network
-
CETTM MTNL
3Overview of PSTN
Public Switched Telephone Network
PSTN - public network for Voice Telephony
Major Components - PSTN Switch (Exchange) - Transmission facilities - Local Loop - Customer Premise Equipment (CPE)
-
CETTM MTNL
4Overview of PSTN
Typical Network
PSTN switch
CPE CPE
Transmission Facilities
PSTN Switch
-
CETTM MTNL
5Overview of PSTN
Public Switched Network
Switched network - Series of inter-linked nodes (switches)
Switches - hardware and/or software devices - capable of creating temporary connections between two or more devices linked to the switch but not to each other
-
CETTM MTNL
6Overview of PSTN
Customer Premise Equipment (CPE)
Term used to identify any piece of equipment supplied by the customer to interface with the PSTN.
CPE devices - POTS/ Telephone Set - FAX/Modems or Data Sets - Private Branch Exchange (PBX) - ISDN Terminals (NT-TA)
-
CETTM MTNL
7Overview of PSTN
External Plant Distributed N/W
U
Analogue subscriber
Pillar
Local Exchange
Pillar
Pillar
DigitalSubscriber
DP
DP
DP
DP
DP DP
DP DP
DPDP
DP
DP
DP
Pillar
-
CETTM MTNL
8Overview of PSTN
External Plant Cable Network
Exchange
Main DistributionFrame
Cable Chamber
Primary Cable
PillarDistributionPoint Box
Secondary Cable
Subscriber's Telephone
Dropwire
-
CETTM MTNL
9Overview of PSTN
Access N/W
Main Distribution
Frame
Digital Room
Local Exchange
DLC (Digital Loop Carrier)
RSU (Remote Subscriber Unit)
Access N/W
Access N/W
Access
N/W
Access N/W
Connecting Cable
Pillar DP
External Plant with DLC and RSU
-
CETTM MTNL
10Overview of PSTN
External network
Exchange
LE
TX system
TX system
TX system
Remote Unit
RU
RU
Subscribers Premises
Double Remote Unit
DRU
Introduction of double remote unit
Subscriber Access Method
-
CETTM MTNL
11Overview of PSTN
Technology specific.- Alcatel- OCB283- RU-RSU(1-4K)& DRU - CNE(0.25K)- Siemens- EWSD- RU- RDLU(1.7K)& DRU - not available- Lucent- 5ESS- RU-RISLU & DRU- Not available
Problems with remote/double remote
Working on proprietary protocols Inter-working not possible
-
CETTM MTNL
12Overview of PSTN
Use of V5.2 in access network
DLCa/b
ISDNBA
BTS
BSC
V5.2
V5.2 LE
DSLAM
INTERNET
V5.2
-
CETTM MTNL
13Overview of PSTN
Open protocol - LE & AN can be of different make - for LE access becomes transparent Subscriber Loop Access on - Wireless - CorDECT, Cellular - Optical Fibre DLC - Copper- 2Mbps -DLC A message based Five Control Protocol Subscriber signals multiplexed in one or more communication
channels
V5.2 Protocol
-
CETTM MTNL
14Overview of PSTN
Local Network Structure
ExchangeArea 5
ExchangeArea 4
ExchangeArea 3
ExchangeArea 2Exchange
Area 1
WireCenter
A
WireCenter
B
-
CETTM MTNL
15Overview of PSTN
Gateway Switch
Hierarchy of Switches
Gateway Switch
Trunk Automatic Exchange
Trunk Automatic Exchange
Tandem Exchange
Tandem Exchange
Tandem Exchange
Trunk Automatic Exchange
Tandem Exchange
Local Exchange
Local Exchange
Local Exchange
Local Exchange
Local Exchange
Local Exchange
Class 1
Class 2 &3
Class 4
Class 5
-
CETTM MTNL
16Overview of PSTN
Hierarchy of Switches
Class 1 - Regional Centre (RC). - "last resort" for final set-up of calls when routes between centres lower in the hierarchy were not available Class 2 - Sectional Centre (SC). - typically connected major toll centres within one/two states Class 3 - Tandem exchanges - connecting major population centres within particular region of the network Class 4 - Tandem exchanges - connecting various areas of a city/towns in a region Class 5 Local Exchanges - subscribers and end-users telephone lines connected
-
CETTM MTNL
17Overview of PSTN
Tandem ExchangeLocal Exchange
Local Exchange
SwitchingSystems
Inter-exchangeTrunks
Local Loop
Local Loop
LocalLong Distance
NLD POPTAX
Typical Exchange Network
-
CETTM MTNL
18Overview of PSTN
Multiple Carrier Network
NLD1
NLD2
NLD3
Region xLong Distance
CarriersRegion y
-
CETTM MTNL
19Overview of PSTN
International Network
ILD1
ILD2
ILD3
Country xInternational
Carriers Country y
INT Gateway
INT Gateway
-
CETTM MTNL
20Overview of PSTN
23 NLDOs & 18 ILDOs licensed to operate
Long Distance Operators
-
CETTM MTNL
21Overview of PSTN
Network Evolution
Earlier Networks (Up to early 70s) - Aanalogue telephone network - Frequency-division multiplexing Present - Local loop analogue - Network digital (based on TDM) Network Migration - IP based switching technology (packet switching, Soft switches, VoIP)
-
CETTM MTNL
22Overview of PSTN
NT Switching Systems
OCB 283 ALCATEL (France)
EWSD SIEMENS (Germany)
FETEX 150 FUJITSU (Japan)
5ESS AT&T (U.S.)
AXE10 ERICSSON (Sweden)
-
CETTM MTNL
23Overview of PSTN
General Architecture of Exchange
C2 C1Subscriber Access
Switching Network
From another Telephone exchange
Trunks Access
To another subscriber or
Telephone Exchange
N/W controller
Control Unit(Call Processing)
O&M Unit(Control Processing
Programs)
-
CETTM MTNL
24Overview of PSTN
PSTN switch (Exchange)
Subscriber interfacing equipment provides access to the customer Trunk interfacing equipment provide access for incoming calls from other
exchanges Switching Network provides path for through connection Control unit, does the call processing control and charging function
-
CETTM MTNL
25Overview of PSTN
Subscriber Facilities
Analogue subscribers facilities Digital subscribers facilities
Bearer services 64kbps circuit switching Circuit switching in 300 bps-3.4 kbps
Teleservices Supplementary services
-
CETTM MTNL
26Overview of PSTN
O&M Function Management/ supervision of incidents Supervision of operation Management of charges and deductions Monitoring of exchange performance Security mechanism
-
CETTM MTNL
27Overview of PSTN
NTSS:O & M Function
Management/ supervision of incidents Monitoring complaints Automatic testing of lines & circuits Display of alarms Precise location of faults Call statistics
-
CETTM MTNL
28Overview of PSTN
NTSS:O & M Function Supervision of operation
Subscribers file Groups Additional services Subscriber Equipment Exchange command Translation, routing Charging No. 7 signalling
-
CETTM MTNL
29Overview of PSTN
NTSS:O & M Function Management of charges and of deductions
LAMA/ CAMA, Domestic meters, Detailed billing, Centralization of accounts, Coin box , time zones, etc.
LAMA-Local automatic message accountingCAMA-Centralised automatic message accounting
-
CETTM MTNL
30Overview of PSTN
NTSS:O & M Function
Monitoring of exchange performanceTrafficSubscriber linesConsistency of charging data
-
CETTM MTNL
31Overview of PSTN
NTSS:O & M Function Security mechanism:
Passwords for workstations and for the operator Non-authorized entry detection
-
CETTM MTNL
32Overview of PSTN
PSTN Numbering Scheme ITU standard E.164 Numbering format E.164 - Country code, Area code and Phone number International public telecommunication number for geographic areas
(maximum 15 digits) Generally International Numbers limited to 12 digits and National Numbers to
10 digits
- Country code- National Destination code (optional)- Subscriber Number
In India PSTN follows SDCA code+Subscriber Number (10 digit)
-
CETTM MTNL
33Overview of PSTN
SUMMARY
Public Switched Network External and Internal elements of PSTN Hierarchy of Switches Different classes of PSTN switchLong Distance (Toll)Network Routing diagram for Long distance calls.PSTN N/W and Components Network evolution General architecture of PSTN-- NT switch.
Slide 1Slide 2Public Switched Telephone NetworkTypical NetworkPublic Switched NetworkCustomer Premise Equipment (CPE)Slide 7External Plant Cable NetworkSlide 9Subscriber Access MethodTechnology specific. Alcatel- OCB283- RU-RSU(1-4K)& DRU - CNE(0.25K) Siemens- EWSD- RU- RDLU(1.7K)& DRU - not available Lucent- 5ESS- RU-RISLU & DRU- Not availableUse of V5.2 in access networkOpen protocol - LE & AN can be of different make - for LE access becomes transparent Subscriber Loop Access on - Wireless - CorDECT, Cellular - Optical Fibre DLC - Copper- 2Mbps -DLC A message based Five Control Protocol Subscriber signals multiplexed in one or more communication channelsLocal Network StructureSlide 15Slide 16Slide 17Multiple Carrier NetworkInternational NetworkSlide 20Network EvolutionSlide 22Slide 23PSTN switch (Exchange)Subscriber FacilitiesO&M FunctionNTSS:O & M FunctionSlide 28Slide 29Slide 30Slide 31PSTN Numbering SchemeSlide 33