Telecommunication Switching system Networks.pdf

Networks Telecommunication Data communication INTEGRATED services

UDHAY PRAKASH P Uday3prakash @gmail.com 10/19/2012

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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.

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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).

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Analog Networks Number of levels in hierarchy of a PSTN depends on the relative costs of transmission and switching in that network.

Small and densely populated countries has shorter distances between its primary centers and large 10/19/2012 TSSN amount of traffic between them.

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Large or sparsely populated countries has longer distances between its primary centers and relatively less JNTUHCEH 4 traffic between primaries.

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). 10/19/2012

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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

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Integrated Digital Network • Many small exchanges are replaced by multiplexers and the remote concentrators, resulting in fewer large capacity junction routes.

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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.

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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. 10/19/2012

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Integrated Services Digital Network

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

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• 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). 4ECE JNTUHCEH

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Integrated Services Digital Network • 1. 2. 3. 4. 5. 6.

7.

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Standard interfaces between the user an d the network include functional units, as: Exchange Termination(ET)—End user connectivity. Line Termination (LT)---BRI or PRI access provisioning. Network Termination(NT1)-terminates access line at customer’s end. Network Termination(NT2)---enables switching functions to be performed. Terminal Equipment (TE1)—provisioning of function required to handle layer 1, 2 & 3 protocols. Terminal Equipment(TE2)—provides functions corresponding to capabilities of existing equipments which do not conform to ITU-T standards. 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.

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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.

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Cellular radio Networks • Trunked radio network Cellular radio network. • Analog and Digital cellular standards. • ANALOG STANDARDS 1. 2. 3. 4. 5. 6. 7.

Advanced Mobile Telephone systems (AMPS) Nordic Mobile Telephone Service(NMT) Total Access Communication System(TACS) Network C Radiocom 2000 Nippon AMPS UNITAX,………

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DIGITAL STANDARDS

1.

DAMPS, GSM, CDMA, UMTS, LTE……….

• Periodic Registration and Handoff. • Home Location Register and Visitor Location Register. 10/19/2012

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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.

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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 10/19/2012

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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 )

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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.

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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))

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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) 10/19/2012

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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 10/19/2012

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Network Management • 1.

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

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All the management aspects were performed using associated software.

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Network Management between various proprietary and non- proprietary networks resulted in the evolution of various STANDARDS.

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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.

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