Networks Telecommunication
Data communication INTEGRATED services
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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.
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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
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.
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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).
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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.
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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
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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.
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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. 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.
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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
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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)
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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
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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.
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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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