Telecommunication Switching system Networks.pdf

Networks Telecommunication

Data communication INTEGRATED services

10/19/2012 1 TSSN 4ECE JNTUHCEH

UDHAY PRAKASH P Uday3prakash @gmail.com

Standards for networks • Standards were deserved to make inter-operability

between the networks of various nations.

• Standardizations include standards for: Transmission plan

Charging Plan

Signaling Plan

Numbering Plan

Routing Plan

Grade of service

Capabilities of switching equipment

Network management

• All these parameters are not independent, but inter-related.


Standards for networks

• Network planning was done to equalize the tradeoff

between performance and cost.

• It is economical to provide circuits more generously

where they are cheap(Customer-access circuits) and

less generously where they are expensive(Trunk

circuits).


Analog Networks

Small and densely populated countries has shorter distances between its primary centers and large amount of traffic between them.

Large or sparsely populated countries has longer distances between its primary centers and relatively less traffic between primaries.

Number of levels in hierarchy of a PSTN depends on the relative costs

of transmission and switching in that network.


Analog Networks • Large networks were later divided into:

1. Long distance carriers, called as Interexchange

carriers(IXC).

2. Local-access and transport areas(LATA) belonging to

local Exchange carriers(LEC).

Each IXC interfaces with a LATA directly to a single point, called point of presence(pop) or routed via an access tandem(AT).


Integrated Digital Network

Analog Networks

Digital Networks

• Low capacity copper cables---high capacity optical fibers.

• Electromechanical analog space division switching system-

Electronic digital time division switching

• Channel associated signaling--common channel signaling.

• Reduced network configuration

• More than one connection to the upper level of hierarchy


Integrated Digital Network • Many small exchanges are

replaced by multiplexers and the

remote concentrators, resulting in

fewer large capacity junction

routes.


Integrated Digital Network

• It is a non-hierarchical network, which

uses dynamic alternative routing.

• Here, one class of tandem switching

centre replaces both the sectional and

regional centers of traditional analog

system.


Integrated Digital Network • Switching Network

• Data links used for common channel

signalling between digital exchanges form a

separate signalling networks.

• As signalling network uses transmission

bearer network channels, synchronizing

network is deserved to synchronize all PCM

frames, to avoid congestion.

• Administrative network is to used to

connect the remote operations and

management centers to the nodes of the

PSTN.

• All these four networks uses the channels in

the basic transmission bearer network.


Integrated Services Digital Network • Extension of IDN to provide wide

variety of services to the customer’s premises.

• Something more(Supplementary services) than the services carried by PSTN.

• In PRI, less than 30 or 23 channels can be provided to obtain channels with greater digit rates for broad applications, as:

H0 channel at 384 kbps.

H11 channel at 1536 kbps(for 1.544 Mbps access.

H12 channel at 1920 kbps(for 2.048 Mbps access).

BRI standardized as ITU-T I.420 PRI standardized as ITU-T I.421


Integrated Services Digital Network • Standard interfaces between the user an d

the network include functional units, as: 1. Exchange Termination(ET)—End user

connectivity.

2. Line Termination (LT)---BRI or PRI access provisioning.

3. Network Termination(NT1)-terminates access line at customer’s end.

4. Network Termination(NT2)---enables switching functions to be performed.

5. Terminal Equipment (TE1)—provisioning of function required to handle layer 1, 2 & 3 protocols.

6. Terminal Equipment(TE2)—provides functions corresponding to capabilities of existing equipments which do not conform to ITU-T standards.

7. Terminal Adapter (TA)—converts layer 1,2&3 protocols of TE2 into those of TE1, to enable equipment on TE2 to operate over the ISDN.


Integrated Services Digital Network • Rapid connection setup and clear

functionality of the switching system.

• supports both circuit switching and packet switching.

• supports point-to-point, multipoint and broadcast connections.

• Support variable data rates, message sizes and call holding times.

• CCITT SS7 protocol is used for interexchange signalling, using the D channel.

• Multimedia terminals.


Cellular radio Networks • Trunked radio network Cellular

radio network.

• Analog and Digital cellular standards.

• ANALOG STANDARDS 1. Advanced Mobile Telephone systems (AMPS)

2. Nordic Mobile Telephone Service(NMT)

3. Total Access Communication System(TACS)

4. Network C

5. Radiocom 2000

6. Nippon AMPS

7. UNITAX,………

• DIGITAL STANDARDS 1. DAMPS, GSM, CDMA, UMTS, LTE……….

• Periodic Registration and Handoff.

• Home Location Register and Visitor Location Register.


Cellular Radio Networks

• Digital transmission minimizes the inter-channel

interference and enables closer channel spacing to be

used.

• Cheaper alternative to cellular radio is tele-point or

cordless service.

• Another alternative: Personal communicator or Pager.


Intelligent Networks For addition of new services:

• Electromechanical systems must deserve new hardware &

modifications to all exchanges.

• SPC systems deserves software upgrade, in all the interconnected

exchanges in the network (costly and time-consuming process).

SOLUTION: To separate software that controls basic functions, such

as call setup, supervising, etc.

Such a network is called INTELLIGENT NETWORK


Intelligent Networks • SPC software is organized in 3 levels:

1. Node Software (provides common utilities

such as signalling, database access,..)

2. Service Logic Programs (controls the

various services, using service independent

building blocks)

3. Service Logic Execution Environment

(program execution environment that hosts

various SLPs and interworks with basic call

control and switching operations of the SSP )


Private Networks • Required for organizations that deserve huge or frequent

transmissions between its offices placed at various geographic

areas.

• In PSTN, voice networks links to PBXs (Voice transmission)

WAN links to their LANs (data transmission)

• Integrated services PBXs enables both voice and data

transmission using same circuits.

• Virtual Private Network----encapsulation of a packet in

another packet.-----secure transmission also.


Numbering • National Numbering scheme

– 10 or 11 digits (area code, exchange code, customer’s no. on local exchange)

• International Numbering Scheme

– 14 digits (Country code, National Number)

• ISDN numbering plan

– 15 digits (Network Destination code(6), Customer address(9))

• Public Data Network

– 14 digits (Data network identification code(4), Network Terminal Number(10))


Charging Plan • Charging based on:

Initial charge for installing the customer’s line

Annual rental or leasing charge

Call charge

• Charging mechanism

1. Flat-rate tariff

2. Message-rate charging

a. Metering based charging (bulk billing)

b. Ticketing based charging (itemized billing)


Routing Plan • Depends on: No. and location of tandem switching centers

No. of levels of tandem switching to be used in the network.

Automatic Alternative routing , condition when to use it. (high usage routing or final routing)

How many exchanges should be interconnected by direct circuits, and how many connected indirectly using tandem switching centers.

• AUTOMATIC ALTERING ROUTING

Switching between High usage routes and the final routes to achieve the deserved grade of service, in overflow conditions

• Overflow control


Network Management • Management to public and private telecom networks is carried out in 4 levels as:

1. Business level-includes sales, customer administration, billing, accounting, inventory

control and investment planning.

2. Service level-includes both basic services(telephony) and value added services.

3. Network level- includes route optimization, traffic management, contingency planning to

cope with emergencies, planning of changes and extensions to the network.

4. Network element level- includes installation of equipment, diagnosis of faults,

maintenance management, repairs and alteration.

• All the management aspects were performed using associated software.

• Network Management between various proprietary and non- proprietary networks

resulted in the evolution of various STANDARDS.


References • J E Flood, “ Telecommunication switching traffic and

networks” Pearson education, ISBN: 9788131705025.

• Theorode Rappaport, “Wireless communications-Principles and Practice”, Pearson publications.

• B Farouzan, “Data Communications and Networking”, TMH.


Documents

Telecommunication Switching system Networks.pdf