Training Report on BSNL

Training Report On Telecom Networks

GWEC, Ajmer

A Practical Training Report

ON

Telecom Networks

Taken at

(Bharat Sanchar Nigam Limited,Ajmer)

Submitted to the Rajasthan Technical University, Kota in Partial fulfillment of the requirement for the degree of

BACHELOR OF TECHNOLOGY

(Session-2010-11)

Submitted to Mr. Gaurav Bharadwaj

HOD, (ECE)

Submitted by Parul Pareek

ECE :

07EEMEC050.

1


ACKNOWLEDGEMENT

I would like to add a few heartfelt words for the people who were part of this training

report in numerous ways, People who gave unending support right from the stage the

training report idea were conceived. In particular I am extremely grateful to BHARAT

SANCHAR NIGAM LIMITED for providing me with an excellent opportunity of

undergoing summer training for the duration of four weeks.

I express my effusive thanks to Mr. S. K. Sharma (S.D.E.) and the other

technical staff members. With their expert guidance and kind help this training would

have been a distant dream.

I express my sincere gratitude to Ms. Kumud (J.T.O.) for providing me the

required information for completion my job.

Parul Pareek

7th Sem. (ECE)

GWEC, Ajmer

GWEC, Ajmer

DEPT.OF ELECTRONICS AND COMMUNICATION ENGG. GOVT.MAHILA ENGINEERING COLLEGE AJMER Nasirabad Road, Makhupura, Ajmer - 305002

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PREFACE

Industrial training is must for every student perusing professional degree because

the ultimate goal of every student is to get the information the industrial training

helps us to get an idea of things.

We should known in order to get a good job i.e. have a good professional

carrier. Industrial training teaches us a lot of things. It helps us to know the kind of

environment we would be getting in an industry and help us to get with the kind of

environment. Industrial training helps us to know what kind of grade an engineer of

specific branch plays in an industry. It help us to get used to working in groups of

known people in it teach us team work because my work in industrial is

accomplished by a group and not an individual.

In totality the industrial teaches us industrial ethics. Some advance technical

knowledge how and help us to acquired with industrial working style.

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INDEX

About BSNL 5

An Overview Of Telecommunication Networks 6

PCM Principle 19

Advanced Optical Networks: DWDM 23

CDMA Technology 28

MLLN 36

Overview Of Intranet 43

Wi-Max 46

Wi-Fi 52

Conclusion 59

Bibliography 60

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1. ABOUT BSNL

Bharat Sanchar Nigam Ltd. Formed in oct. 2000, is world’s 7th largest

telecommunications company providing comprehensive range of telecom services in

India: wire line, CDMA mobile, GSM mobile, internet, broadband, carrier services.

Within a span it has become the one of the largest public sector unit in India.

BSNL is the only service provider, making focused efforts and planned initiatives to

bridge the rural –urban digital divide ICT sector. In fact there is no telecom operator in

the country to beat it reach with its wide network giving services I every nook & corner

of country and operates across India except Delhi & Mumbai.

BSNL cellular service cellone, has more than 20.7 million cellular customers, garnering

24 % of all mobile users as its subscribers. That means that almost every fourth mobile

user in the country has a BSNL connection. In basic services, BSNL is miles ahead of its

rivals, with 35.1 million Basic Phone Subscribers i.e. 85 % share of the subscribers and

92 % share in revenue terms.

BSNL has set up a world class multi-gigabit, multi-protocol convergent IP infrastructure

that provides convergent services like voice, data and video through the same Backbone

and broadband access network. At present there are 0.6 million Data one broadband

customers.

The company has vast experience in Planning, Installation, network integration and

Maintenance of Switching & Transmission Networks and also has a world class ISO

9000 certified Telecom Training Institute. BSNL plans to expand its customer base from

present 73 millions lines to 125 million lines and infrastructure investment plan to the

tune of Rs. 733 crores (US$ 16.67 million) in the next three years. Today, BSNL is

India's largest Telco and one of the largest Public Sector Undertaking with estimated

market value of $ 100 Billion. The company is planning an IPO with in 6 months to

offload 10% to public in the Rs 300-400 range valuing the company at over $100 billion.

The turnover, nationwide coverage, reach, comprehensive range of the telecom services

and the desire to excel has made BSNL the no. 1 telecom company of India.

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2. AN OVERVIEW OF TELECOMMUNICATION NETWORK

Institutional Mechanism and Role

Introduction: All industries operate in a specific environment which keeps changing and

the firms in the business need to understand it to dynamically adjust their actions for best

results. Like minded firms get together to form associations in order to protect their

common interests. Other stake holders also develop a system to take care of their issues.

Governments also need to intervene for ensuring fair competition and the best value for

money for its citizens. This handout gives exposure on the Telecom Environment in India

and also dwells on the role of international bodies in standardizing and promoting

Telecom Growth in the world.

Institutional Framework: It is defined as the systems of formal laws, regulations, and

procedures, and informal conventions, customs, and norms, that broaden, mold, and

restrain socio-economic activity and behaviour. In India, The Indian telegraph act of 1885

amended from time to time governs the telecommunications sector. Under this act, the

government is in-charge of policymaking and was responsible for provisioning of

services till the opening of telecom sector to private participation. The country has been

divided into units called Circles, Metro Districts, Secondary Switching Areas (SSA), and

Long Distance Charging Area (LDCA) and Short Distance Charging Area (SDCA).

Major changes in telecommunications in India began in the 1980s. The initial phase of

telecom reforms began in 1984 with the creation of

Center for Department of Telematics (C-DOT) for developing indigenous technologies

and private manufacturing of customer premise equipment. Soon after, the Mahanagar

Telephone Nigam Limited (MTNL) and Videsh Sanchar Nigam Limited (VSNL) were

set up in 1986. The Telecom Commission was established in 1989. A crucial aspect of

the institutional reform of the Indian telecom sector was setting up of an independent

regulatory body in 1997 - the Telecom Regulatory Authority of India (TRAI), to assure

investors that the sector would be regulated in a balanced and fair manner. In 2000, DoT

corporatized its services wing and created Bharat Sanchar Nigam Limited. Further

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changes in the regulatory system took place with the TRAI Act of 2000 that aimed at

restoring functional clarity and improving regulatory quality and a separate disputes

settlement body was set up called Telecom Disputes Settlement and Appellate Tribunal

(TDSAT) to fairly adjudicate any dispute between licensor and licensee, between service

provider, between service provider and a group of consumers. In October 2003, Unified

Access Service Licenses regime for basic and cellular services was introduced. This

regime enabled services providers to offer fixed and mobile services under one license.

Since then, Indian telecom has seen unprecedented customer growth crossing 600 million

connections. India is the fourth largest telecom market in Asia after China, Japan and

South Korea. The Indian telecom network is the eighth largest in the world and the

second largest among emerging economies. A brief on telecom echo system and various

key elements in institutional framework is given below:

Department of Telecommunications: In India, DoT is the nodal agency for taking care

of telecom sector on behalf of government. Its basic functions are:

Policy Formulation

Review of performance

Licensing

Wireless spectrum management

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Administrative monitoring of PSUs

Research & Development

Standardization/Validation of Equipment

International Relations

Main wings within DoT:

Telecom Engineering Center (TEC)

USO Fund

Wireless Planning & Coordination Wing (WPC)

Telecom Enforcement, Resource and Monitoring (TERM) Cell

Telecom Centers of Excellence (TCOE)

Public Sector Units:

Bharat Sanchar Nigam Limited(BSNL)

Indian Telephone Industries Limited (ITI)

Mahanagar Telephone Nigam Limited(MTNL)

Telecommunications Consultants India Limited(TCIL)

R & D Unit:

Center for development of Telematics (C-DoT)

The other key governmental institutional units are TRAI & TDSAT. Important units are

briefed below:

Telecom Engineering Center (TEC): It is a technical body representing the interest of

Department of Telecom, Government of India. Its main functions are:

Specification of common standards with regard to Telecom network equipment,

services and interoperability.

Generic Requirements (GRs), Interface Requirements (IRs).

Issuing Interface Approvals and Service Approvals.

Formulation of Standards and Fundamental Technical Plans.

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Interact with multilateral agencies like APT, ETSI and ITU etc. for

standardization.

Develop expertise to imbibe the latest technologies and results of R&D.

Provide technical support to DOT and technical advice to TRAI & TDSAT.

Coordinate with C-DOT on the technological developments in the Telecom Sector

for policy planning by DOT.

Universal Service Obligation Fund (USO): This fund was created in 2002. This fund is

managed by USO administrator. All telecom operators contribute to this fund as per

government policy. The objective of this fund is to bridge the digital divide i.e. ensure

equitable growth of telecom facilities in rural areas. Funds are allocated to operators who

bid lowest for providing telecom facilities in the areas identified by USO administrator.

Wireless Planning & Coordination (Wpc): This unit was created in 1952 and is the

National Radio Regulatory Authority responsible for Frequency Spectrum Management,

including licensing and caters for the needs of all wireless users (Government and

Private) in the country. It exercises the statutory functions of the Central Government and

issues licenses to establish, maintain and operate wireless stations. WPC is divided into

major sections like Licensing and Regulation (LR), New Technology Group (NTG) and

Standing Advisory Committee on Radio Frequency Allocation (SACFA). SACFA makes

the recommendations on major frequency allocation issues, formulation of the frequency

allocation plan, making recommendations on the various issues related to International

Telecom Union (ITU), to sort out problems referred to the committee by various wireless

users, Sitting clearance of all wireless installations in the country etc.

Telecom Enforcement, Resource and Monitoring (TERM) Cell: In order to ensure

that service providers adhere to the license conditions and for taking care of telecom

network security issues, DoT opened these cells in 2004 and at present 34 cells are

operating in various Circles and big districts in the country. Key functions of these units

are Inspection of premises of Telecom and Internet Service Providers, Curbing illegal

activities in telecom services, Control over clandestine / illegal operation of telecom

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networks by vested interests having no license, To file FIR against culprits, pursue the

cases, issue notices indicating violation of conditions of various Acts in force from time

to time, Analysis of call/subscription/traffic data of various licensees, arrangement for

lawful interception / monitoring of all communications passing through the licensee's

network, disaster management, network performance monitoring, Registration of OSPs

and Telemarketers in License Service Areas etc..

Telecom Centers of Excellence (TCOE): (www.tcoe.in) The growth of Indian

Telecommunications sector has been astounding, particularly in the last decade. This

growth has been catalyzed by telecommunications sector liberalization and reforms.

Some of the areas needing immediate attention to consolidate and maintain the growth

are:

Capacity building for industry talent pool

Continuous adaptation of the regulatory environment to facilitate

induction/adaptation of high potential new technologies and business models

Bridging of high rural - urban teledensity /digital divide

Faster deployment of broadband infrastructure across the country

Centers of Excellence have been created to work on:

(i) Enhancing talent pool,

(ii) Technological innovation,

(iii) Secure information infrastructure and

(iv) Bridging of digital divide.

These COEs are also expected to cater to requirements of South Asia as regional leaders.

The main sponsor (one of the telecom operators), the academic institute where the

Centers are located and the tentative field of excellence are enumerated in the table

below:

Field of Excellence in Telecom

Associated

Institute

Sponsor

Next Generation Network & Network Technology

IIT, Kharagpur Vodafone Essar

Telecom Technology & Management IIT, Delhi Bharti Airtel

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Technology Integration, Multimedia & Computational Math

IIT, Kanpur BSNL

Telecom Policy, Regulation, Governance, Customer Care & Marketing

IIM, Ahmadabad IDEA Cellular

Telecom Infrastructure & Energy IIT, Chennai Reliance

Disaster Management of Info systems & Information Security

IISc, Bangalore Aircel

Rural Application IIT Mumbai Tata Telecom

Spectrum Management (Proposed) WPC, Chennai Govt with Industryconsortium

Telecom Regulatory Authority of India (TRAI): TRAI was established under TRAI

Act 1997 enacted on 28.03.1997. The act was amended in 2000. Its Organization setup

consists of One Chairperson, Two full-time members & Two part-time members. Its

primary role is to deals with regulatory aspects in Telecom Sector & Broadcasting and

Cable services. TRAI has two types of functions as mentioned below:

Mandatory Functions :

o Tariff policies

o Interconnection policies

o Quality of Service

o Ensure implementation of terms and conditions of license

Recommendatory Functions

New license policies

Spectrum policies

Opening of sector

Telecom Dispute Settlement Appellate Tribunal (TDSAT): TDSAT was established in

year 2000 by an amendment in TRAI act by transferring the functions of dispute handling

to new entity i.e. TDSAT. The organization setup consists of one Chairperson & two full-

time members. Its functions are:

1. Adjudicate any dispute between

licensor and licensee

two or more licensees

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group of consumers

2. Hear & dispose off appeal against any direction, decision or order of the Authority

under TRAI Act

Key International Standardization Bodies for Telecom sector:

ITU: It is the leading United Nations agency for information and communication

technology issues, and the global focal point for governments and the private sector in

developing networks and services. For nearly 145 years, ITU has coordinated the shared

global use of the radio spectrum, promoted international cooperation in assigning satellite

orbits, worked to improve telecommunication infrastructure in the developing world,

established the worldwide standards that foster seamless interconnection of a vast range

of communications systems and addressed the global challenges of our times, such as

mitigating climate change and strengthening cyber security. Vast spectrum of its work

area includes broadband Internet to latest-generation wireless technologies, from

aeronautical and maritime navigation to radio astronomy and satellite-based meteorology,

from convergence in fixed-mobile phone, Internet access, data, voice and TV

broadcasting to next-generation networks. ITU also organizes worldwide and regional

exhibitions and forums, such as ITU TELECOM WORLD, bringing together the most

influential representatives of government and the telecommunications and ICT industry

to exchange ideas, knowledge and technology for the benefit of the global community,

and in particular the developing world. ITU is based in Geneva, Switzerland, and its

membership includes 191 Member States and more than 700 Sector Members and

Associates. On 1 January 2009, ITU employed 702 people from 83 different countries.

The staff members are distributed between the Union's Headquarters in Geneva,

Switzerland and eleven field offices located around the world. Www.itu.int

Asia Pacific Telecommunity: Headquartered at Bangkok, the APT is a unique

organization of Governments, telecom service providers, manufactures of

communication equipment, research & development organizations and other stake

holders active in the field of communication and information technology. APT serves as

the focal organization for communication and information technology in the Asia Pacific

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region. The APT has 34 Members, 4 Associate Members and 121 Affiliate Members. The

objective of the Telecommunity is to foster the development of telecommunication

services and information infrastructure throughout the region with a particular focus on

the expansion thereof in less developed areas. APT has been conducting HRD Program

for developing the skills of APT Members to meet the objectives of APT. The topics

include Information Communication Technologies (ICT), Network and Information

Security, Finance and Budget, Telecommunication Management, Mobile

communications, Multimedia, Satellite Communication, Telecommunications and ICT

Policy and Regulation, Broadband Technologies, e-Applications, Rural

Telecommunications Technologies, IP Networks and Services, Customer Relations, etc.

Www.aptsec.org

The European Telecommunications Standards Institute: (ETSI) produces globally-

applicable standards for Information and Communications Technologies (ICT), including

fixed, mobile, radio, converged, broadcast and internet technologies. It is officially

recognized by the European Union as a European Standards Organization. ETSI is a not-

for- profit organization with more than 700 ETSI member organizations drawn from 62

countries across 5 continents world-wide. ETSI unites Manufacturers, Network operators,

National Administrations, Service providers, Research bodies, User groups,

Consultancies. This cooperation has resulted in a steady stream of highly successful ICT

standards in mobile, fixed, and radio communications and a range of other standards that

cross these boundaries, including Security, Satellite, Broadcast, Human Factors, Testing

& Protocols, Intelligent transport, Power-line telecoms, e-Health, Smart Cards,

Emergency communications, GRID & Clouds, Aeronautical etc. ETSI is consensus-based

and conducts its work through Technical Committees, which produce standards and

specifications, with the ETSI General Assembly and Board. Www.etsi.org

BSNL: Bharat Sanchar Nigam Limited was formed in year 2000 and took over the

service providers role from dot. Today, BSNL has a customer base of over 9 crore and is

the fourth largest integrated telecom operator in the country. BSNL is the market leader

in Broadband, landline and national transmission network. BSNL is also the only

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operator covering over 5 lakh village with telecom connectivity. Area of operation of

BSNL is all India except Delhi & Mumbai.

MTNL: Mahanagar Telephone Nigam Limited, formed in 1984 is the market leader in

landline and broadband in its area of operation. Www.mtnl.net.in

TCIL: TCIL, a prime engineering and consultancy company, is a wholly owned

Government of India Public Sector Enterprise. TCIL was set up in 1978 for providing

Indian telecom expertise in all fields of telecom, Civil and IT to developing countries

around the world. It has its presence in over 70 countries. Www.tcil-india.com

ITI: Indian telephone Industries is the oldest manufacturing unit for telephone

instruments. To keep pace with changing times, it has started taking up manufacturing of

new technology equipment such as GSM, OFC equipment, Invertors, Power plants,

Defense equipments, Currency counting machines etc. Www.itiltd-india.com

Centre for Development of Telematics (cdot): This is the R & D unit under dot setup in

1984. The biggest contribution of this centre to Indian telecom sector is the development

of low capacity (128 port) Rural automatic Exchange (RAX) which enabled provisioning

of telephone in even the smallest village. This was specially designed to suit Indian

environment, capable of withstanding natural temperature and dusty conditions.

Prominent Licenses provided by DoT:

o Access Service (CMTS & Unified Access Service): The Country is divided into

23 Service Areas consisting of 19 Telecom Circle Service Areas and 4 Metro

Service Areas for providing Cellular Mobile Telephone Service (CMTS).

Consequent upon announcement of guidelines for Unified Access (Basic&

Cellular) Services licenses on 11.11.2003, some of the CMTS operators have been

permitted to migrate from CMTS License to Unified Access Service License

(UASL). No new CMTS and Basic service Licenses are being awarded after

issuing the guidelines for Unified access Service License (UASL). As on 31

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March 2008, 39 CMTS and 240 UASL licenses operated.

o 3G & BWA (Broadband Wireless Access): Department of Telecom started the

auction process for sale of spectrum for 3G and BWA (WiMax) in April 2010 for

22 services areas in the country. BSNL & MTNL have already been given

spectrum for 3G and BWA and they need to pay the highest bid amount as per

auction results. BSNL & MTNL both are providing 3G services. BSNL has rolled

out its BWA service by using WiMax technology.

o Mobile Number Portability (MNP) Service: Licenses have been awarded to two

operators to provide MNP in India. DoT is ensuring the readiness of all mobile

operators and expects to start this service any time after June 2010.

o Infrastructure Provider: There are two categories IP-I and IP-II. For IP-I the

applicant company is required to be registered only. No license is issued for IP-I.

Companies registered as IP-I can provide assets such as Dark Fiber, Right of

Way, Duct space and Tower. This was opened to private sector with effect from

13.08.2000. An IP-II license can lease / rent out /sell end to end bandwidth i.e.

digital transmission capacity capable to carry a message. This was opened to

private sector with effect from 13.08.2000. Issuance of IP-II License has been

discontinued w.e.f. 14.12.05

o INMARSAT: INMARSAT (International Maritime Satellite Organization)

operates a constellation of geo-stationary satellites designed to extend phone, fax

and data communications all over the world. Videsh Sanchar Nigam Ltd (VSNL)

is permitted to provide Inmarsat services in India under their International

Long Distance(ILD) license granted by Department of

Telecommunications(dot). VSNL has commissioned their new Land Earth

Station (LES) at Delhi, Pune compatible with 4th generation INMARSAT

Satellites (I-4) and INMARSAT-B, M, Mini-M & M-4 services are now

being provided through this new LES after No Objection Certificate (NOC) is

issued by dot on case by case basis.

o National Long Distance: There is no limit on number of operators for this

service and license is for 20 years.

o International Long Distance: This was opened to private sector on 1st April

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2002 with no limit on number of operators. The license period is 20 years.

o Resale of IPLC: For promoting competition and affordability in

International Private Leased Circuits (IPLC) Segment, Government permitted

the "Resale of IPLC" by introducing a new category of License called as -

"Resale of IPLC" Service License with effect from 24th September 2008. The

Reseller can provide end-to-end IPLC between India and country of destination

for any capacity denomination. For providing the IPLC service, the Reseller has

to take the IPLC from International Long Distance (ILD) Service Providers

licensed and permitted to enter into an arrangement for leased line with Access

Providers, National Long Distance Service Providers and International Long

Distance Service Providers for provision of IPLC to end customers.

o Sale of International Roaming SIM cards /Global Calling Cards in India:

The cards being offered to Indian Customers will be for use only outside India.

However, if it is essential to activate the card for making test calls/emergent calls

before the departure of customer and /or after the arrival of the customer, the

same shall be permitted for forty eight (48) hours only prior to departure from

India and twenty four (24) hours after arrival in India.

o Internet without Telephony: The Internet Service Provider (ISP) Policy was

announced in November, 98. ISP Licenses, which prohibit telephony on

Internet ,are being issued starting from 6.11.98 on non-exclusive basis. Three

category of license exist namely A,B and C. A is all India, B is telecom Circles,

Metro Districts and major districts where as C is SSA wide.

o Internet with Telephony: Only ISP licensees are permitted, within their service

area, to offer Internet Telephony service. The calls allowed are PC to PC in

India, PC in India to PC/Telephone outside India, IP based calls from India to

other countries.

o VPN: Internet Service Providers (isps) can provide Virtual Private Network

(VPN) Services. VPN shall be configured as Closed User Group (CUG) only and

shall carry only the traffic meant for the internal use of CUG and no third party

traffic shall be carried on the VPN. VPN shall not have any connectivity with

PSTN / ISDN / PLMN except when the VPN has been set up using Internet

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access dial-up facility to the ISP node. Outward dialing facility from ISP node is

not permitted.

o VSAT & Satellite Communication: There are two types of CUG VSAT

licenses : (i) Commercial CUG VSAT license and (ii) Captive CUG VSAT

license. The commercial VSAT service provider can offer the service on

commercial basis to the subscribers by setting up a number of Closed User

Groups (cugs) whereas in the captive VSAT service only one CUG can be set up

for the captive use of the licensee. The scope of the service is to provide data

connectivity between various sites scattered within territorial boundary of India

via INSAT Satellite System using Very Small Aperture Terminals (VSATs).

However, these sites should form part of a Closed User Group (CUG). PSTN

connectivity is not permitted.

o Radio Paging: The bids for the Radio Paging Service in 27 cities were invited in

1992, the licenses were signed in 1994 and the service was commissioned in

1995. There was a provision for a fixed license fee for first 3 years and review of

the license fee afterwards. The license was for 10 years and in 2004 Govt offered

a extended 10 years license with certain license fee waivers but with the wide

spread use of mobile phones, this service has lost its utility.

o PMRTS: Public Mobile Radio Trunking service allows city wide connectivity

through wireless means. This service is widely used by Radio Taxi operators and

companies whose workforce is on the move and there is need to locate the present

position of employee for best results. PSTN connectivity is permitted.

o INSAT MSS: INSAT Mobile Satellite System Reporting Service (INSAT MSS

Reporting Service) is a one way satellite based messaging service available

through INSAT. The basic nature of this service is to provide a reporting channel

via satellite to the group of people, who by virtue of their nature of work are

operating from remote locations without any telecom facilities and need to send

short textual message or short data occasionally to a central station.

o Voice Mail/ Audiotex/ UMS (Unified Messaging Service): Initially a seprate

license was issued for these services. For Unified Messaging Service, transport of

Voice Mail Messages to other locations and subsequent retrieval by the subscriber

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must be on a non- real time basis. For providing UMS under the license, in

addition to the license for Voice Mail/Audiotex/UMS, the licensee must also have

an ISP license. The ISP license as well as Voice Mail/Audiotex/ UMS license

should be for the areas proposed to be covered by UMS service. Since start of

NTP-99, all access provider i.e. CMTS, UASL, Fixed service providers are also

allowed to provide these services as Value Added Service (VAS) under their

license conditions.

o Telemarketing: Companies intending to operate as Telemarketes need to obtain

this license from DoT.

o Other Service Provider (including BPO): As per New Telecom Policy (NTP)

1999, Other Service Providers (OSP), such as tele-banking, tele-medicine, tele-

trading, e- commerce, Network Operation Centers and Vehicle Tracking Systems

etc are allowed to operate by using infrastructure provided by various access

providers for non-telecom services.

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3. PCM PRINCIPLE

Introduction

A long distance or local telephone conversation between two persons could be

provided by using a pair of open wire lines or underground cable as early as early as

mid of 19th century. However, due to fast industrial development and increased

telephone awareness, demand for trunk and local traffic went on increasing at a rapid rate.

To cater to the increased demand of traffic between two stations or between two

subscribers at the same station we resorted to the use of an increased number of pairs on

either the open wire alignment, or in underground cable. This could solve the problem for

some time only as there is a limit to the number of open wire pairs that can be installed on

one alignment due to headway consideration and maintenance problems. Similarly

increasing the number of open wire pairs that can be installed on one alignment due to

headway consideration and maintenance problems. Similarly increasing the number of

pairs to the underground cable is uneconomical and leads to maintenance problems.

It, therefore, became imperative to think of new technical innovations which

could exploit the available bandwidth of transmission media such as open wire lines or

underground cables to provide more number of circuits on one pair. The technique used

to provide a number of circuits using a single transmission link is called Multiplexing.

Multiplexing Techniques

There are basically two types of multiplexing techniques

i. Frequency Division Multiplexing (FDM)

ii Time Division Multiplexing (TDM)

Frequency Division Multiplexing Techniques (FDM)

The FDM technique is the process of translating individual speech circuits (300-

3400 Hz) into pre-assigned frequency slots within the bandwidth of the transmission

medium. The frequency translation is done by amplitude modulation of the audio

frequency with an appropriate carrier frequency. At the output of the modulator a filter

network is connected to select either a lower or an upper side band. Since the intelligence

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is carried in either side band, single side band suppressed carrier mode of AM is used.

This results in substantial saving of bandwidth mid also permits the use of low power

amplifiers. Please refer Fig. 1.

FDM techniques usually find their application in analogue transmission systems. An

analogue transmission system is one which is used for transmitting continuously varying

signals.

Fig. 1 FDM Principle

Time Division Multiplexing

Basically, time division multiplexing involves nothing more than sharing

a transmission medium by a number of circuits in time domain by establishing a

sequence of time slots during which individual channels (circuits) can be transmitted. Thus

the entire bandwidth is periodically available to each channel. Normally all time slots1 are

equal in length. Each channel is assigned a time slot with a specific common repetition

period called a frame interval. This is illustrated in Fig. 2.

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Fig. 2 Time Division Multiplexing

Each channel is sampled at a specified rate and transmitted for a fixed duration. All

channels are sampled one by, the cycle is repeated again and again. The channels are

connected to individual gates which are opened one by one in a fixed sequence. At the

receiving end also similar gates are opened in unison with the gates at the transmitting

end.

The signal received at the receiving end will be in the form of discrete

samples and these are combined to reproduce the original signal. Thus, at a given

instant of time, only one channel is transmitted through the medium, and by sequential

sampling a number of channels can be staggered in time as opposed to transmitting all

the channel at the same time as in EDM systems. This staggering of channels in time

sequence for transmission over a common medium is called Time Division

Multiplexing (TDM).

Pulse Code Modulation

It was only in 1938; Mr. A.M. Reaves (USA) developed a Pulse Code

Modulation (PCM) system to transmit the spoken word in digital form. Since then

digital speech transmission has become an alternative to the analogue systems.

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PCM systems use TDM technique to provide a number of circuits on the same

transmission medium viz. open wire or underground cable pair or a channel provided by

carrier, coaxial, microwave or satellite system.

Basic Requirements for PCM System

To develop a PCM signal from several analogue signals, the following

processing steps are required

• Filtering

• Sampling

• Quantization

• Encoding

• Line Coding

Signaling In Telecommunications

The term signaling, when used in telephony, refers to the exchange of control

information associated with the establishment of a telephone call on a

telecommunications circuit. An example of this control information is the digits dialed by

the caller, the caller's billing number, and other call-related information.

When the signaling is performed on the same circuit that will ultimately carry the

conversation of the call, it is termed Channel Associated Signaling (CAS). This is the

case for earlier analogue trunks, MF and R2 digital trunks, and DSS1/DASS PBX trunks.

In contrast, SS7 signaling is termed Common Channel Signaling (CCS) in that the

path and facility used by the signaling is separate and distinct from the

telecommunications channels that will ultimately carry the telephone conversation. With

CCS, it becomes possible to exchange signaling without first seizing a facility, leading to

significant savings and performance increases in both signaling and facility usage.

GWEC, Ajmer 22


4. ADVANCED OPTICAL NETWORKS: DWDM

Introduction

The revolution in high bandwidth applications and the explosive growth of the Internet,

however, have created capacity demands that exceed traditional TDM limits. To meet

growing demands for bandwidth, a technology called Dense Wavelength Division

Multiplexing (DWDM) has been developed that multiplies the capacity of a single fiber.

DWDM systems being deployed today can increase a single fiber’s capacity sixteen fold,

to a throughput of 40 Gb/s. The emergence of DWDM is one of the most recent and

important phenomena in the development of fiber optic transmission technology. Dense

wavelength-division multiplexing (DWDM) revolutionized transmission technology by

increasing the capacity signal of embedded fiber. One of the major issues in the

networking industry today is tremendous demand for more and more bandwidth. Before

the introduction of optical networks, the reduced availability of fibers became a big

problem for the network providers. However, with the development of optical networks

and the use of Dense Wavelength Division Multiplexing (DWDM) technology, a new

and probably, a very crucial milestone is being reached in network evolution. The

existing SONET/SDH network architecture is best suited for voice traffic rather than

today’s high-speed data traffic. To upgrade the system to handle this kind of traffic is

very expensive and hence the need for the development of an intelligent all-optical

network. Such a network will bring intelligence and scalability to the optical domain by

combining the intelligence and functional capability of SONET/SDH, the tremendous

bandwidth of DWDM and innovative networking software to spawn a variety of optical

transport, switching and management related products.

In traditional optical fiber networks, information is transmitted through optical fiber by a

single light beam. In a wavelength division multiplexing (WDM) network, the vast

optical bandwidth of a fiber (approximately 30 THz corresponding to the low-loss region

in a single-mode optical fiber) is carved up into wavelength channels, each of which

carries a data stream individually. The multiple channels of information (each having a

different carrier wavelength) are transmitted simultaneously over a single fiber. The

reason why this can be done is that optical beams with different wavelengths propagate

GWEC, Ajmer 23


without interfering with one another. When the number of wavelength channels is above

20 in a WDM system, it is generally referred to as Dense WDM or DWDM.

DWDM technology can be applied to different areas in the telecommunication networks,

which includes the backbone networks, the residential access networks, and also the

Local Area Networks (LANs). Among these three areas, developments in the DWDM-

based backbone network are leading the way, followed by the DWDM-based LANs. The

development on DWDM-based residential access networks seems to be lagging behind at

the current time.

Development Of DWDM Technology

Early WDM began in the late 1980s using the two widely spaced wavelengths in the

1310 nm and 1550 nm (or 850 nm and 1310 nm) regions, sometimes called wideband

WDM. The early 1990s saw a second generation of WDM, sometimes called

narrowband WDM, in which two to eight channels were used. These channels were now

spaced at an interval of about 400 GHz in the 1550-nm window. By the mid-1990s, dense

WDM (DWDM) systems were emerging with 16 to 40 channels and spacing from 100 to

200 GHz. By the late 1990s DWDM systems had evolved to the point where they were

capable of 64 to 160 parallel channels, densely packed at 50 or even 25 GHz intervals.

As fig. 1 shows, the progression of the technology can be seen as an increase in the

number of wavelengths accompanied by a decrease in the spacing of the wavelengths.

Along with increased density of wavelengths, systems also advanced in their flexibility of

configuration, through add-drop functions, and management capabilities.

GWEC, Ajmer 24


Figure 1 Evolution of DWDM

Varieties Of WDM

Early WDM systems transported two or four wavelengths that were widely spaced.

WDM and the “follow-on” technologies of CWDM and DWDM have evolved well

beyond this early limitation.

WDM

Traditional, passive WDM systems are wide-spread with 2, 4, 8, 12, and 16 channel

counts being the normal deployments. This technique usually has a distance limitation

of less than 100 km.

CWDM

Today, coarse WDM (CWDM) typically uses 20-nm spacing (3000 GHz) of up to 18

channels. The CWDM Recommendation ITU-T G.694.2 provides a grid of

wavelengths for target distances up to about 50 km on single mode fibers as specified

in ITU-T Recommendations G.652, G.653 and G.655. The CWDM grid is made up of

18 wavelengths defined within the range 1270 nm to 1610 nm spaced by 20 nm.

DWDM

GWEC, Ajmer 25


Dense WDM common spacing may be 200, 100, 50, or 25 GHz with channel count

reaching up to 128 or more channels at distances of several thousand kilometers with

amplification and regeneration along such a route.

DWDM System Components

Figure 3 shows an optical network using DWDM techniques that consists of five main

components:

1. Transmitter (transmit transponder):

- Changes electrical bits to optical pulses

- Is frequency specific

- Uses a narrowband laser to generate the optical pulse

2. Multiplexer/ demultiplexer:

- Combines/separates discrete wavelengths

3. Amplifier:

- Pre-amplifier boosts signal pulses at the receive side

- Post-amplifier boosts signal pulses at the transmit side (post amplifier) and on

the receive side (preamplifier)

- In line amplifiers (ILA) are placed at different distances from the source to

provide recovery of the signal before it is degraded by loss.

- EDFA (Erbium Doped Fiber Amplifier) is the most popular amplifier.

4. Optical fiber (media):

- Transmission media to carry optical pulses

- Many different kinds of fiber are used

5. Receiver (receive transponder)

- Changes optical pulses back to electrical bits

- Uses wideband laser to provide the optical pulse

GWEC, Ajmer 26


Figure 3: DWDM System Components

Benefits of DWDM

• Increases bandwidth (speed and distance)

• Does not require replacement or upgrade their existing legacy systems

• Provides "next generation" technologies to meet growing data needs

• Less costly in the long run because increased fiber capacity is automatically

available; don't have to upgrade all the time.

GWEC, Ajmer 27


5. CDMA Technology

Access Network:

Access network, the network between local exchange and subscriber, in the

Telecom Network accounts for a major portion of resources both in terms of capital and

manpower. So far, the subscriber loop has remained in the domain of the copper cable

providing cost effective solution in past. Quick deployments of subscriber loop, coverage

of inaccessible and remote locations coupled with modern technology have led to the

emergence of new Access Technologies. The various technological options available are

as follows:

1. Multi Access Radio Relay

2. Wireless in Local Loop

3. Fiber in the Local Loop

Wireless in Local Loop (WILL)

Fixed Wireless telephony in the subscriber access network also known as Wireless in

Local Loop (WLL) is one of the hottest emerging market segments in global

telecommunications today. WLL is generally used as “the last mile solution” to deliver

basic phone service expeditiously where none has existed before. Flexibility and

expediency are becoming the key driving factors behind the deployment of WILL.

WLL shall facilitate cordless telephony for residential as well as commercial complexes

where people are highly mobile. It is also used in remote areas where it is uneconomical

to lay cables and for rapid development of telephone services. The technology employed

shall depend upon various radio access techniques, like FDMA, TDMA and CDMA.

Different technologies have been developed by the different countries like CT2 from

France, PHS from Japan, DECT from Europe and DAMPS & CDMA from USA. Let us

discuss CDMA technology in WLL application as it has a potential ability to tolerate a

fair amount of interference as compared to other conventional radios. This leads to a

considerable advantage from a system point of view.

GWEC, Ajmer 28


Spread Spectrum Principle:

Originally Spread spectrum radio technology was developed for military use to counter

the interference by hostile jamming. The broad spectrum of the transmitted signal gives

rise to “Spread Spectrum”. A Spread Spectrum signal is generated by modulating the

radio frequency (RF) signal with a code consisting of different pseudo random binary

sequences, which is inherently resistant to noisy signal environment.

A number of Spread spectrum RF signals thus generated share the same frequency

spectrum and thus the entire bandwidth available in the band is used by each of the users

using same frequency at the same time.

Fig-1 CDMA ACCESS – A CONCEPT

On the receive side only the signal energy with the selected binary sequence code is

accepted and original information content (data) is recovered. The other users signals,

whose codes do not match contribute only to the noise and are not “despread” back in

bandwidth (Ref Fig-1) This transmission and reception of signals differentiated by

“codes” using the same frequency simultaneously by a number of users is known as Code

Division Multiple Access (CDMA) Technique as opposed to conventional method of

Frequency Division Multiple Access and Time Division Multiple Access.

In the above figure, it has been tried to explain that how the base band signal of 9.6 Kbps

is spread using a Pseudo-random Noise (PN) source to occupy entire bandwidth of 1.25

MHz. At the receiving end this signal will have interference from signals of other users of

the same cell, users of different cells and interference from other noise sources. All these

GWEC, Ajmer 29


signals get combined with the desired signal but using a correct PN code the original data

can be reproduced back. CDMA channel in the trans and receive direction is a FDD

(Frequency Division Duplexing) channel. The salient features of a typical CDMA system

are as follows:

Frequency of operation: 824-849Mhz and 869-894 MHz

Duplexing Method: Frequency Division Duplexing (FDD)

Access Channel per carrier: Maximum 61 Channels

RF Spacing: 1.25 MHz

Coverage: 5 Km with hand held telephones and approx.

20 Km with fixed units.

Introduction to CDMA 2000-1X

Network entity description: Base station subsystem (BSS) Base station subsystem is the

general term for the wireless devices and wireless channel control devices that serve one

or several cells. Generally, a BSS contains one more base station controllers (BSC) and

base transmitter stations (BTS).

GWEC, Ajmer 30


Mobile switch center (MSC)

MSC is a functional entity that performs control and switching to the mobile stations

within the area that it serves, and an automatic connecting device for the subscriber

traffic between the CDMA network and other public networks or other MSCs. MSC is

the kernel of the CDMA cellular mobile communication system, and it is different from a

wired switch in that an MSC must consider the allocation of the wireless resources and

the mobility of subscribers, and at least it must implement the follows processing

activities:

1. Location Registration processing;

2. Handoff.

Gateway MSC (GMSC)

When a non-CDMA subscriber calls a CDMA subscriber, the call will first be routed to

an MSC, which will inquires the corresponding HLR and further route the call to the

called party’s MSC. This kind of MSC is called Gateway MSC (GMSC). It is up to the

network operator to select which MSCs as GMSCs.

Visitor location register (VLR)

VLR is responsible for the storage and updating of the subscriber data of mobile stations

that roamed to the service area of this VLR. The VLR is generally configured together

with the MSC. When the mobile station enters a new location area, the MSC will notice

the VLR, which will initiate registration processing to the HLR to update the subscriber

location information. The VLR also stores necessary information for the establishment of

calls in the database for the MSC to search. One VLR can cover one or more MSC areas.

Home location register (HLR)

The HLR provides subscriber information storage and management functions for the

mobile network, including mobile subscriber subscription and cancellation and service

authorization and cancellation. At the same time, it helps in the implementation of

subscriber’s call and service operations. A CDMA can contain one or more HLRs based

on the number of subscribers, equipment capacity and network organization mode, with

GWEC, Ajmer 31


multi-HLR mode realized in the form of virtual HLRs. The subscriber information stored

in the HLR includes the following two types in information:

1. Subscription information

2. Subscriber-related information stored in the HLR

Authentication center (AUC)

Authentication center is a function entity for the management of authentication

information related to the mobile station. It implement mobile subscriber authentication,

stores the mobile subscriber authentication parameters, and is able to generate and

transmit the corresponding authentication parameters based on the request from

MSC/VLR. The authentication parameters in the AUC can be stored in the encrypted

form. The authentication center is generally configured together with the HLR. The

authentication parameter stored in the AUC includes:

1. Authentication key (A_KEY);

2. Share secret data (SSD);

3. Mobile identification number/international mobile subscriber identity (MIN/IMSI);

4. Authentication algorithm (AAV);

5. Accounting (COUNT).

Short message center (MC or SC)

As an independent entity in the CDMA cellular mobile communication system, the short

message center works in coordination with other entities such as MSC, HLR to

implement the reception, storing and transfer of the short messages from CDMA cellular

mobile communication system subscribers, and store subscriber-related short message

data.

Short message entity (SME)

SME is a function entity for synthesis and analysis of short messages.

Operation and maintenance Center (OMC)

The OMC provides the network operator with network operation and maintenance

services, manages the subscriber information and implements network planning, to

GWEC, Ajmer 32


enhance the overall working efficiency and service quality of the system. There two type

of operation and maintenance centers: OMC-S and OMC-R. An OMC-S is mainly used

for the maintenance work at the mobile switching subsystem (MSS) side; an OMC-R is

mainly used for the maintenance work at the base station subsystem (BSS) side.

Third Generation Standards

CDMA2000/FDD-MC — CDMA2000 using Frequency Division Duplexing-

Multicarrier (FDD-MC) mode. Here multicarrier implies N x 1.25 MHz

channels overlaid on N existing IS-95 carriers or deployed on unoccupied spectrum.

CDMA2000 includes:

1. 1x —using a spreading rate of 1.2288 Mcps

2. 3x —using a spreading rate of 3 x 1.2288 Mcps or 3.6864 Mcps

3. 1xEV-DO (1x Evolution - Data Optimized)—using a spreading rate of

1.2288 Mcps optimized for data

WCDMA/FDD-DS —Wideband CDMA (WCDMA) Frequency Division

Duplexing-Direct Sequence spreading (FDD-DS) mode. This has a single 5 MHz

channel. WCDMA uses a single carrier per channel and employs a spreading rate of

3.84 Mcps.

UTRA TDD/ TD-SCDMA — Universal Mobile Telephone Services Terrestrial

Radio Access (UTRA) and TD-SCDMA. These are Time Division Duplexed

(TDD) standards aimed primarily at asymmetric services used in unpaired (i.e., no

separate uplink and downlink) bands. TD-SCDMA is based on a synchronous

Time Division scheme for TDD and wireless local loop applications. The frame

and slot structure are the same as W-CDMA. However, in TDD mode each slot

can be individually allocated either the uplink or the downlink.

EV-DO

EV-DO is a mobile technology that facilitates higher throughput on mobile platform.

The third generation of cellular standards has seen a dominance of CDMA as the

GWEC, Ajmer 33


underlying access technology. UMTS (Universal Mobile Telecommunication Services) is

3G evolution for GSM world. The standardization work for UMTS is being carried-out

by 3GPP. The standardization work for CDMA 2000 and its enhancements is being

carried out under the supervision of 3GPP2.

1x Evolution-Data Optimized, abbreviated as EV-DO or 1xEV-DO, is an evolution of

CDMA 2000 1x to support higher data rates. It is defined in TIA (Telecommunication

Industry Association) standard IS 856. It is commonly referred to as DO. It is officially

termed as "CDMA2000, High Rate Packet Data Air Interface". Working on same carrier

bandwidth of 1.25 MHz as CDMA 2000 1x systems, 1xEV-DO provides significantly

higher data rates to Access Terminals (mobile devices). Downlink data rates supported

are up to 2.4576 Mb/s in Rev. 0 and up to 3.1 Mb/s in Rev. A.

Traditional wireless networks create a physical path between receiving and sending

devices, much like traditional telephone networks. EVDO instead adopts the same

approach used for the internet. IP, the Internet Protocol, breaks data into small pieces

called packets. Each packet is sent independently of all the other packets. This saves

bandwidth for use by other devices; when neither party on a phone call is speaking, the

connection consumes no bandwidth because there are no packets to send. Radio resources

are allocated only at the time of actual data transfer leading to better spectral efficiency.

EV-DO does not support voice services. In Forward link supports data rates up to 2.4576

Mbps. There is no power control in Forward Link. Peak data rate in Reverse Link is

153.6 kbps.

Generic Model of CDMA 2000 1x EVDO System:

A generic model of a CDMA 2000 1 x EV-DO System typically consists of:

a) Access Network (AN) consisting of Radio Node (RN) & Radio Network Controller

b) Packet Core Network (PCN)

a) Radio Node (RN): It is a multiple circuit transceiver which shall radiate to cover a cell

or a sector. It consists of radio modules, base band signal processor, network interface,

antenna, feeder etc. It can be co-located with RNC or remotely located. RN shall include

GWEC, Ajmer 34


the functions related to channel coding/decoding, interleaving, encryption, frame

building, modulation/demodulation, RF transceiver, antenna diversity, low noise

amplification etc. as per CDMA 2000 1 x EV-DO standards.

The AN obtains the timing reference and positioning reference from the GPS system

and hence the GPS receiver shall form an integral part of the RN along with other fixtures

such as GOS antenna, cable etc. AN split mounting arrangements with tower mountable

RF components such as PAs, LNAs, Filters etc. are also acceptable.

b) Radio Network Controller (RNC): It is responsible for inter connection between the

RN and the PCN and it provides control and management for one or more RNs. It assigns

traffic channels to individual users, monitors system performance and provides interface

between the RN and the PCN. RNC performs the radio processing functions such as

management of the radio resources, radio channel management, local connection

management etc.

It also processes information required for decision on handover of calls from one RN to

another. RNC can be collocated with the PCN or remotely located. The Packet Control

Function (PCF) shall form an integral part of RNC.

Packet Core Network (PCN): The packet data core network provides packet data

services to Access Terminal (AT) and consists of PDSN, HA, AAA, AN-AAA and

FA functionalities. The functional entities AAA and ANAAA may be a single physical

entity or two separate physical entities.

Operations and Maintenance Centre (OMC): The Operations and Maintenance Centre

(OMC) allow the centralized operation of the various units in the system and the

functions needed to maintain the sub systems. The OMC provides the dynamic

monitoring and controlling of the network management functions for operation and

maintenance.

GWEC, Ajmer 35


6. LEASED LINES

And

MLLN- MANAGED LEASED LINE NETWORK

Leased Lines

A leased line is a permanent fiber optic or telephone connection between two

points set up by a telecommunications carrier. A leased line is also sometimes referred to

as a dedicated line. They can be used for telephone, data, or Internet services. Oftentimes

businesses will use a leased line to connect to geographically distant offices because it

guarantees bandwidth for network traffic. For example, a bank may use a leased line in

order to easily transfer financial information from one office to another. A leased line can

span long or short distances and customers generally pay a flat monthly rate for the

service depending on the distance between the two points. Leased lines do not have

telephone numbers because each side of the line is always connected to one another, as

opposed to telephone lines which reuse the same lines for numerous conversations

through a process called "switching." The information sent through the leased line travels

along dedicated secure channels, eliminating the congestion that occurs in shared

networks.

MLLN – MANAGED LEASED LINE NETWORK

The MLLN service is specially designed mainly for having effective control and

monitoring on the leased line so that the down time is minimized and the circuit

efficiency is increased. This mainly deals with data circuits ranging from 64 Kbps to

2048 Kbps.

NETWORK ARCHITECTURE:

GWEC, Ajmer 36

http://www.wisegeek.com/what-is-bandwidth.htm


Fig. 1 Network Architecture of MLLN

DXC

Capacity

DXC (64 ports upgradeable to 128 ports)



DXC (256 ports)

1/0 cross-connect capability

Non-Blocking Architecture

Redundancy

GWEC, Ajmer 37

Main DXC256 Ports

DXC-64 DXC-64 DXC-128

VMUXs

Modems


Power Supply

Switching Matrix

Cross-connect Memory

Expansion to be made possible by addition of cards only.

Fully Managed from Centralized NMS

VMUX

Type - I, Type - II, Type - III with the configurations given below

64 kbps N*64 kbps E1 Links

VMUX Type I 32 8 12

VMUX Type II 16 4 4

VMUX Type III 8 4 4

Expansion to be made possible on the same chassis by addition of cards

Type III VMUX

> 230V AC Powered

> -48V DC Powered

VMUX to be able to extend hotline circuits

> Point to point and Point to Multi-point circuit routing should be

possible

HDSL Driving Distance:

> 3.5km at 2Mbps

> 5 km at 1Mbps

> 7km for 64/128kbps (at 0.5mm dia copper cable

GWEC, Ajmer 38


NTU (Network Terminating Unit)

Capacity

> 64/128kbps NTU with V.35

> 64/128kbps NTU with G.703

> N x 64kbps NTU with V.35

> N x 64kbps NTU with G.703

> N x 64kbps NTU with Ethernet Interface

Line Loop Testing as per ITU-T Rec V.54

64kbps NTU to work up to 128kbps

N x 64kbps NTU to work up to 2Mbps

NTU to send power off signal to the NMS at the time of NTU getting switched off.

STU-160 works up to 128kbps

CTU-S and CTU-R works up to 2Mbps on a single pair of copper

All NTU’s support V.54 line loop testing and support dying gasp to send power off signal

at time of power off condition.

NMS (Network Management System)

o MLLN NMS

o Billing and Accounting System

o Web Self-care system

o We have offered Tellabs Network Manager Release 13 to meet the requirements

o MLLN NMS performs all the management functions on the network

o Supports regional partitioning and VPN capabilities

o Offered Performance Monitoring, Recovery, Reporting Packages

GWEC, Ajmer 39


o Offered HP Open view and Cisco works which would reside on SNMP server for

managing the servers and IT elements

Different Nodes Used in MLLN

A node can be described as a digital multiplexer equipped with several trunk

interfaces and as a digital cross-connect device equipped with several channel interfaces.

The cluster node is used in the network as a high capacity cross-connection device with

several subracks. The basic nodes and midi nodes are used as flexible multiplexers or

medium capacity cross-connect equipment. They have both one subrack.

Cluster Node:-

It is built in Master-slave architecture. The cluster node represents the largest

node of the System. It is built in master-slave architecture. It consists of a master sub rack

and 1 - 8 slave sub racks. Slave sub racks can be either double (32 unit slots), single (16

unit slots) or midi (8 unit slots) sub racks.

The maximum cross-connect port capacity of a cluster node is

8 * 64 Mbit/s = 512 Mbit/s = 256 * 2048 kbit/s port = 64 * 8448 kbit/s port. Each slave

sub rack brings 64 Mbit/s to the cross-connect port capacity. The cluster node can be

expanded without disturbing the existing traffic. The cluster node cross-connects at TS

(64 kbit/s) level. The cluster node’s master subrack is mechanically similar to the double

subrack in the basic node. The difference is that the motherboard and bus extender cards

are different.

Basic Node:-

The Basic Node is the basic building block of the system. (16 unit slot). It is used

in local exchange or backbone networks or customer premises networks, depending on

the needed services and application. The cross connect port capacity of a Basic node is 64

Mbps = 32*2048 kbps port = 8*8448 kbps port

Midi Node:-

It is a small size flexible access node for customer premises. Midi node has the

same cross-connect functionality as the basic node (64 Mbps) One slot wide

GWEC, Ajmer 40


multifunctional interface unit XCG designed for the Midi node. Midi node supports

mainly the same interface units as the basic node.

Mini Node:-

The mini node is a small cross-connect device, which can operate as either part of

the network connected to the network manager or as a separate cross-connect device

controlled and supervised locally. The mini node is functionally very close to the basic

node. The main difference is that in the mini node the common units (Control Unit,

Cross-connection Unit and Power Supply Unit) are integrated to the node.

The cross-connect port capacity of a mini node is 64 Mbit/s. It supports 2-4

interface modules with 1, 2, 5 or 10 interfaces each. Due to this limitation of the number

of interfaces, it is impossible to use all the cross-connection capacity available. The

cross-connection capabilities of a mini node are the same as in SXU-A unit in a basic

node. mini nodes can make cross-connections both at 64 kbit/s and 8 kbit/s level, the bit

level cross-connection capacity is 95 TS and CAS cross-connection capacity is 32 TS.

Typically mini nodes are used as an access level node in a network or as base station

transmission equipment in mobile networks.

Tellabs 8170 cluster node

Tellabs 8110 network terminating unit Tellabs 8120 mini nodeTellabs 8130 micro node

Tellabs 8150 basic node Tellabs 8140 midi node

Tellabs 8160 accelerator node A111

Tellabs 8170 cluster node

Tellabs 8110 network terminating unit Tellabs 8120 mini nodeTellabs 8130 micro node

Tellabs 8150 basic node Tellabs 8140 midi node

Tellabs 8160 accelerator node A111

Fig. 3 Different Nodes

GWEC, Ajmer 41


Micro node : The total cross-connection capacity of a micro node is 64 Mbit/s. The

micro node is fully non-blocking. They can make cross-connections both at time slot and

at bit level. The bit level cross-connection capacity is 127 TS (8128 kbit/s). micro nodes

do not support CAS signalling. The cross-connection delay is one frame (125 s).

The accuracy of the internal clock is ± 30 ppm and it supports both fallback list

and quality levels. The micro node does not have a build-in test generator or a receiver

for circuit loop testing.

Accelerator Node:-

It is an access node combining PDH and SDH technologies.

PDH features:-

-Support for many existing interfaces units

-Two X-buses and consequently 2 x 64 Mbps = 128 Mbps capacity

Application e.g. DSLAM

Cross connections are done only at TS level, 64 kbps.

Operated with the network manager

Switch Node:-

It is an N.E with ADM, LTM and SDXC. Operated with the network manager

GWEC, Ajmer 42


7. OVERVIEW OF INTRANET

WHAT IS INTRANET

Smaller private version of Internet. It uses Internet protocols to create enterprise-

wide network which may consists of interconnected LANs.

It may or may not include connection to Internet.

Intranet is an internal information system based on Internet technology and web

protocols for implementation within a corporate organization.

This implementation is performed in such a way as to transparently deliver the

immense informational resources of an organization to each individual’s desktop

with minimal cost, time and efforts.

The Intranet defines your organization and display it for everyone to see.

If everyone knows

what the company stands for,

what the company’s strategic vision is,

what the guiding company principles are,

who the clients and partners are,

then they can focus more clearly on what their own contributions are to the organization.

Every organization can constantly refer to the central messages and develop their own

supporting sites accordingly. Use the Web as an information, communications, and

project-management tool across the organization.

Who needs an Intranet?

In an Intranet environment is used to communicate over two or more networks across

different locations.

GWEC, Ajmer 43


1. Users having multi-locations with multi-networks.

2. Users having single locations with multi-networks.

3. Users having single locations with single networks.

What’s really HOT about Intranets?

From a technology point of view, an Intranet is simply beautiful. because:

1. It is scaleable.

2. It is Interchangeable.

3. It is platform independent

4. It is Hardware independent.

5. It is vendor independent.

Why Intranet for an Organization:

Quick access to voice, video, data and other resources needed by users.

Variety of valuable applications of Intranet applications improve communication

and productivity across all areas of an enterprise.

An Intranet can give immediate access to products specifications, pricing charts and new

collateral’s, sales lead, competitive information and list of customer wins including

profit/loss analysis, thus boosting the success of the business.

A Typical Intranet setup

GWEC, Ajmer 44


Technical Overview Of The Intranet Technology

Intranet runs on open TCP/IP network, enable companies to employ the same type of

servers and browser used for World Wide Web for internal applications distributed over

the corporate LAN.

A typical Intranet implementation involves a high end machine called a server which can

be accessed by individual PCs commonly referred to as clients, through the network.

The Intranet site setup can be quite inexpensive, especially if your users are already

connected by LAN. Most popular Intranet web servers can run on a platform widely

found in most organizations. Basic requirements for setting up an intranet site are:

Requirements:

Software:

Server : OS can be Windows server, Unix, LINUX .Web Server s/w should be

installed

Client : OS can be Windows workstation, LINUX .Web Browser software

Hardware:

Server: 4 GB RAM, 360 GB secondary storage, Pentium processor with CD

ROM.

Client: 1GB RAM, 180 GB Secondary storage, Pentium processor.

GWEC, Ajmer 45


8. Wi-MAX

Introduction:

Broadband wireless sits at the confluence of two of the most remarkable growth stories of

the telecommunications industry in recent years. Both wireless and broadband have on

their own enjoyed rapid mass-market adoption. The staggering growth of the Internet is

driving demand for higher-speed Internet-access services, leading to a parallel growth in

broadband adoption.

So what is broadband wireless? Broadband wireless is about bringing the

broadband experience to a wireless context, which offers users certain unique benefits

and convenience. There are two fundamentally different types of broadband wireless

services. The first type attempts to provide a set of services similar to that of the

traditional fixed-line broadband but using wireless as the medium of transmission. This

type, called fixed wireless broadband, can be thought of as a competitive alternative to

DSL or cable modem. The second type of broadband wireless, called mobile broadband,

offers the additional functionality of portability, nomadicity and mobility. Mobile

broadband attempts to bring broadband applications to new user experience scenarios and

hence can offer the end user a very different value proposition. Wi-MAX is an acronym

that stands for World-wide Interoperability for Microwave Access and this technology

is designed to accommodate both fixed and mobile broadband applications.

EVOLUTION OF BROADBAND WIRELESS

WiMAX technology has evolved through four stages, albeit not fully distinct or

clearly sequential: (1) narrowband wireless local-loop systems, (2) first-generation line-

of-sight (LOS) broadband systems, (3) second-generation non-line-of-sight (NLOS)

broadband systems, and (4) standards-based broadband wireless systems.

GWEC, Ajmer 46


Wimax And Other Broadband Wireless Technologies

WiMAX is not the only solution for delivering broadband wireless services. WiMAX

occupies a somewhat middle ground between Wi-Fi and 3G technologies when compared

in the key dimensions of data rate, coverage, QoS, mobility, and price. Table provides a

summary comparison of WiMAX with 3G and Wi-Fi technologies.

Table Comparison of WiMAX with Other Broadband Wireless Technologies

Parameter Fixed WiMAX Mobile WiMAX HSPA 1x EV-DO

Rev A

Wi-Fi

Standards IEEE 802.16-

2004

IEEE 802.16e-2005 3GPP Release 6 3GPP2 IEEE 802.11a/g/n

Parameter Fixed WiMAX Mobile WiMAX HSPA 1x EV-DO

Rev A

Wi-Fi

Peak down

link data

rate

9.4Mbps in

3.5MHz with

3:1 DL-to-UL

ratio TDD;

6.1Mbps with

1:1

46Mbps with 3:1 DL-

to-UL ratio TDD;

32Mbps with 1:1

14.4Mbps

using all 15

codes;

7.2Mbps with 10

codes

3.1Mbps;

Rev.

B will support

4.9Mbps

54 Mbpsshared

using 802.11a/g;

more than

100Mbps peak

layer 2 throughput

using 802.11n

Peak uplink

data rate

3.3Mbps in

3.5MHz using

3:1 DL-to-UL

ratio; 6.5Mbps

with 1:1

7Mbps in 10MHz

using 3:1 DL-to-UL

ratio; 4Mbps using

1:1

1.4Mbps

initially;

5.8Mbps later

1.8Mbps

Bandwidth 3.5MHz and 3.5MHz, 7MHz, 5MHz 1.25MHz20MHz for

GWEC, Ajmer 47

http://www.wimax.com/commentary/wimax_weekly/1-4-wimax-and-other-broadband-wireless-technologies


7MHz in

3.5GHz band;

10MHz in

5.8GHz band

5MHz, 10MHz, and

8.75MHz initially

802.11a/g;

20/40MHz for

802.11n

Modulation QPSK, 16

QAM, 64 QAM

QPSK, 16 QAM, 64

QAM

QPSK, 16 QAMQPSK,

8 PSK, 16

QAM

BPSK, QPSK, 16

QAM, 64 QAM

Multiplexin

g

TDM TDM/OFDMA TDM/CDMA TDM/CDMA CSMA

Duplexing TDD, FDD TDD initially FDD FDD TDD

Frequency 3.5GHz and

5.8GHz

initially

2.3GHz, 2.5GHz, and

3.5GHz initially

800 / 900 / 1,800

/ 1,900/ 2,100

MHz

800/900/1,80

0/1,900MHz

2.4GHz, 5GHz

Coverage

(typical)

3–5 miles < 2 miles 1–3 miles 1–3 miles < 100 ft indoors; <

1000 ft outdoors

Mobility Not applicable Mid High High Low

A broad industry consortium, the WiMAX Forum has begun certifying broadband

wireless products for interoperability and compliance with a standard. WiMAX is based

on wireless metropolitan area networking (WMAN) standards developed by the IEEE

802.16 group and adopted by both IEEE and the ETSI HIPERMAN group.

WiMAX NETWORK ARCHITECTURE

The WiMAX NWG has developed a network reference model to serve as an architecture

framework for WiMAX deployments and to ensure interoperability among various

GWEC, Ajmer 48


WiMAX equipment and operators. The network reference model envisions a unified

network architecture for supporting fixed, nomadic, and mobile deployments and is based

on an IP service model. Below is simplified illustration of an IP-based WiMAX network

architecture. The overall network may be logically divided into three parts:

1. Mobile Stations (MS) used by the end user to access the network.

2. The access service network (ASN), which comprises one or more base stations

and one or more ASN gateways that form the radio access network at the edge.

3. Connectivity service network (CSN), which provides IP connectivity and all the

IP core network functions.

The network reference model developed by the WiMAX Forum NWG defines a number

of functional entities and interfaces between those entities. Fig below shows the logical

representation of the network architecture.

GWEC, Ajmer

Mobile Subscriber Station

BS

BS ASN GW(FA)

HA

ASN

CSN

Another ASN

Another Operator’s CSN

NAPNSP

R1

R2

R6

R3

R4

R5

49

AAA


ASN-ACCESS SERVICES NETWORKNAP-NETWORK ACCESS PROVIDER CSN- CORE SERVICES NETWORKNSP- NETWORK SERVICES PROVIDER BS- BAS STATIONHA-HOME AGENTFA-FOREGN AGENTAAA-AUTHENTICATION AUTHONZATION & ACCOUNTING

Fig. WiMAX Network Reference Model

Base Station (Bs): The BS is responsible for providing the air interface to the MS.

Additional functions that may be part of the BS are micro mobility management

functions, such as handoff triggering and tunnel establishment, radio resource

management, QoS policy enforcement, traffic classification, DHCP (Dynamic Host

Control Protocol) proxy, key management, session management, and multicast group

management.

Access Service Network Gateway (Asn-Gw): The ASN gateway typically acts as a

layer 2 traffic aggregation point within an ASN. Additional functions that may be part

of the ASN gateway include intra-ASN location management and paging, radio

resource management and admission control, caching of subscriber profiles and

encryption keys, AAA client functionality, establishment and management of

mobility tunnel with base stations, QoS and policy enforcement, foreign agent

functionality for mobile IP, and routing to the selected CSN.

Connectivity Service Network (Csn): The CSN provides connectivity to the

Internet, ASP, other public networks, and corporate networks. The CSN is owned by

the NSP and includes AAA servers that support authentication for the devices, users,

and specific services. The CSN also provides per user policy management of QoS and

security. The CSN is also responsible for IP address management, support for

roaming between different NSPs, location management between ASNs, and mobility

and roaming between ASNs, subscriber billing and inter operator settlement, inter-

CSN tunneling to support roaming between different NSPs.

GWEC, Ajmer 50


Reference Points: The WiMAX NWG defines a reference point as a conceptual link

that connects two groups of functions that reside in different functional entities of the

ASN, CSN or MS. Reference points may not be a physical interface except when the

functional entities on either side of it are implemented on different physical devices.

Reference point End points Description

R1 MS and CSN Implements the air interface ( IEEE

802.16e ) specifications.

R2 MS and CSN For authentication, authorization, IP host

configuration management and mobility

management, only a logical interface

between MS and CSN

R3 ASN and CSN Supports AAA, policy enforcement,and

mobility mgmt. capabilities

R4 ASN and ASN A set of protocols originating/terminating

in various entities within the ASN. In

Release I , R4 is the only interoperable

interface between different ASNs or

heterogenous ASNs.

R5 CSN and CSN A set of protocols for interworking

between home and visited network.

R6 BS and ASN-GW A set of control and bearer plane

protocols for communication between BS

and ASN-GW. It may serve as a conduit

for exchange of different MAC states

information between neighboring BSs.

R7 ASN-GW-DP

and ASN-GW-

EP

An optional set of control plane protocols

for co-ordination between two group of

functions identified in R6.

R8 BS and BS A set of control plane message flows and

bearer plane data flows between BSs to

GWEC, Ajmer 51


ensure fast and seamless handover.

9. AN INTRODUCTION TO W I RELESS-F I DELITY (WI-FI)

Scope:

Wi-Fi is a registered trademark by the Wi-Fi Alliance. The products tested and approved

as "Wi-Fi Certified" are interoperable with each other, even if they are from different

manufacturer. It is Short form for “Wireless-Fidelity” and is meant to generically refer

to any type of ‘802.11’ network, whether ‘802.11’b, ‘802.11’a, dual-band, etc.

General description of Wi-Fi Network:

A Wi-Fi network provides the features and benefits of traditional LAN technologies such

as Ethernet and Token Ring without the limitations of wires or cables. It provides the

final few metres of connectivity between a wired network and the mobile user thereby

providing mobility, scalability of networks and the speed of installation.

WIFI is a wireless LAN Technology to deliver wireless broad band speeds up to 54 Mbps

to Laptops, PCs, PDAs , dual mode wifi enabled phones etc.

In a typical Wi-Fi configuration, a transmitter/receiver (transceiver) device, called the

Access Point (AP), connects to the wired network from a fixed location using standard

cabling. A wireless Access Point combines router and bridging functions, it bridges

network traffic, usually from Ethernet to the airwaves, where it routes to computers with

wireless adapters. The AP can reside at any node of the wired network and acts as a

gateway for wireless data to be routed onto the wired network as shown in Figure-1. It

supports only 10 to 30 mobile devices per Access Point (AP) depending on the network

GWEC, Ajmer 52

http://www.webopedia.com/TERM/W/Wi_Fi.html#%23


traffic. Like a cellular system, the Wi-Fi is capable of roaming from the AP and re-

connecting to the network through another AP. The Access Point (or the antenna attached

to the Access Point) is usually mounted high but may be mounted essentially anywhere

that is practical as long as the desired radio coverage is obtained.

Figure -1: A typical Wi-Fi Network.

Like a cellular phone system, the wireless LAN is capable of roaming from the AP and

re-connecting to the network through other APs residing at other points on the wired

network. This can allow the wired LAN to be extended to cover a much larger area than

the existing coverage by the use of multiple APs such as in a campus environment as

shown in Figure 2.

GWEC, Ajmer 53


Figure -2: Extending Wi-Fi coverage with multiple APs.

An important feature of the wireless LAN is that it can be used independent of a wired

network. It may be used as a stand alone network anywhere to link multiple computers

together without having to build or extend a wired network. Then a peer to peer

workgroup can be established for transfer or access of data. A member of the workgroup

may be established as the server or the network can act in a peer to peer mode as Shown

in Figure-3.

Figure-3: Wireless LAN workgroup.

GWEC, Ajmer 54


End users access the Wi-Fi network through Wi-Fi adapters, which are implemented as

cards in desktop computers, or integrated within hand-held computers. Wi-Fi wireless

LAN adapters provide an interface between the client Network Operating System (NOS)

and the airwaves via an antenna. The nature of the wireless connection is transparent to

the NOS. Wi-Fi deals with fixed, portable and mobile stations and of course, the physical

layers used here are fundamentally different from wired media.

Wi-Fi Network Configuration:

A Wireless Peer-To-Peer Network: This mode is also known as ADHOC mode. Wi-Fi

networks can be simple or complex. At its most basic, two PCs equipped with wireless

adapter cards can set up an independent network whenever they are within range of one

another. This is called a peer-to-peer network. It requires no administration or pre-

configuration. In this case, each client would only have access to the resources of the

other client and not to a central server as shown in Figure-4.

Figure-4: A Wi-Fi Peer-To-Peer Network.

Client and Access Point:

This is known as INFRASTUCTURE mode and is normally employed. However,

wireless gateway can be configured to enable peer to peer communication in this mode as

well.

In this mode, one Access Point is connected to the wired network and each client would

have access to server resources as well as to other clients. The specific number client

depends on the number and nature of the transmissions involved. Many real-world

applications exist where a single Access Point services from 15 to 50 client devices as

shown in Figure-5.

GWEC, Ajmer 55


Figure-5: A Server and Clint Wi-Fi Network.

Multiple Access Points and Roaming:

Access points can be connected to each other through UTP cable or they can be

connected to each other over radio through wireless bridging. There is an option to

connect access points in a mesh architecture where in event of a fault in an access point

the network heals itself and connectivity is ensured through other access point. This

changeover takes place dynamically.

Access Points have a finite range, of the order of 500 feet indoor and 1000 feet outdoors.

In a very large facility such as a warehouse, or on a college campus, it will probably be

necessary to install more than one Access Point. Access Point positioning is done by a

site survey. The goal is to blanket the coverage area with overlapping coverage cells so

that clients might range throughout the area without ever losing network contact. The

ability of clients to move seamlessly among a cluster of Access Points is called roaming.

Access Points hand the client off from one to another in a way that is invisible to the

client, ensuring unbroken connectivity as shown in Fig-6.

GWEC, Ajmer 56


Figure-6: Multiple Access Points and Roaming.

Use of an Extension Point: To solve particular problems of topology, the network

designer some times uses Extension Points (EPs) to augment the network of Access

Points (APs). Extension Points look and function like Access Points, but they are not

tethered to the wired network as are APs. EPs function just as their name implies: they

extend the range of the network by relaying signals from a client to an AP or another EP.

EPs may be strung together in order to pass along messaging from an AP to far-flung

clients as shown in Figure-7.

Figure -7: Wi-Fi network with Extension Point (EP).

The Use of Directional Antennae: One last item of wireless LAN equipment to consider

is the directional antenna. Let’s suppose you had a Wi-Fi network in your building-A and

wanted to extend it to a leased building-B, one mile away. One solution might be to

install a directional antenna on each building, each antenna targeting the other.

GWEC, Ajmer 57


The antenna on ‘A’ is connected to your wired network via an Access Point. The antenna

on ‘B’ is similarly connected to an Access Point in that building, which enables Wi-Fi

network connectivity in that facility as shown in Figure-8.

Figure-8: A Wi-Fi network using Directional Antennae.

Abbreviations:

1. LAN: Local Area Network.

2. AP: Access Point.

3. EP: Extension Point.

4. ISM: Industrial scientific & medical

5. MAC: Media Access Control.

6. CSMA/CA: Carrier Sense multiple Access with

Collision Avoidance.

7. CDMA 2000 1x EV-DO: CDMA 2000 1x Evolution Version Data

Only.

8. IEEE: Institute of Electrical & Electronics Engineers.

9. OSI: Open systems Interconnect.

10. WEP: Wireless Equivalent Privacy.

GWEC, Ajmer 58


CONCLUSION

I saw various division of C.T.O. Compound Ajmer Exchange and tried to group as much

as I could, which switched my knowledge and logic. As a student of ECE. I learned

Telecom Networks which is mainly concerned with my focus area.

At last, I would like to say thanks again all staff of the unit who helped me

through my training period.

THANKS!

GWEC, Ajmer 59


PARUL PAREEKFinal Year

ECE GWEC, AJMER

Bibliography

1. Material provided by BSNL training center.

2. www.wikipedia.org

3. www.tec.gov.in

4. www.tcoe.in

5. www.tdsat.nic.in

6. www.itu.int

7. www.aptsec.org

8. www.etsi.org

GWEC, Ajmer 60

http://www.etsi.org/

http://www.aptsec.org/

http://www.itu.int/

http://www.tdsat.nic.in/

http://www.tcoe.in/

http://www.tec.gov.in/

http://www.wikipedia.org/


9. www.mtnl.net.in

10.www.tcil-india.com

11.www.itiltd-india.com

GWEC, Ajmer 61

http://www.tcil-india.com/

http://www.mtnl.net.in/

Documents

Training Report on BSNL