report

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CHAPTER 1
1. INTRODUCTION
Bharat Sanchar Nigam Limited (BSNL) with a turnover of more than Rs. 35,812 core and net
profit of Rs. 575 crore for the financial year 2008-09 is one of the largest telecom Service
providers in India. The Company has about 4.5 crore line basic telephone Capacity, 0.8 crore
Wireless in Local Loop and 5.2 crore Global System of Mobile Communications capacity. The
Company also maintains a large transmission network Comprising optical fiber cables and
microwave systems through which 7,330 cities/towns And 5.5 lakh villages in the country are
connected. Transmission systems form the backbone of the telecommunication network.
‘Overhead wires’ used to be the transmission media in India which later gave way to co-
axial/copper cables and was followed by Radio frequency based system. With the advent of
Optical Fiber Cable (OFC), which works on digital technology, Bharat Sanchar Nigam Limited
started using OFCfor creating transmission network. Apart from these, BSNL also use Satellite
Systems as a transmission medium.Telecom Maintenance Regions of BSNL are responsible
for the maintenance of long-distance transmission systems in the country. The long distance
network maintenance of BSNL is divided into four regions – Eastern Telecom Region (ETR),
Northern Telecom Region (NTR), Southern Telecom Region (STR) and Western Telecom
Region (WTR). Each Region is headed by a Chief General Manager (CGM). The four
Maintenance Regions control more than 19,100 route kilometers of optical fiber cables and
microwave systems functioning in the country. During the year 2008-09 the total expenditure
on the upkeep and maintenance of the long distance transmission systems was Rs. 393.52 crore.
With the entry of private service providers into the telecommunication sector all operators
essentially required interconnection with BSNL network. Interconnection facilities for
National Long Distance (NLD) and International Long Distance (ILD) to the operators are
provided by BSNL at their Level I Trunk Automation

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CHAPTER 2
2. MPLS VPN, MLLN AND LEASED CIRCUIT
Keeping pace with the technological trend to provide latest and varied value added services
to its customers, BSNL harnesses Infrastructure based on MPLS Technology to offer world
class IPVPN services.
Fig. 2.1 MPLS VPN MLLN AND LEASED CIRCUIT
MPLS is an acronym for "Multi-Protocol Label Switching". MPLS VPN is a technology that
allows a Service Provider like BSNL to have complete control over parameters that are critical
to offering its customers service guarantees with regard to bandwidth Throughputs, latencies
and availability. The technology enables Secure Virtual Private Networks (VPN) to be built
and allows Scalability that will make it possible for BSNL to offer assured Growth to its Rather
than setting up and managing individual point-to-point Circuits between each office using pair
of Leased Lines, MPLS VPN Customers need to provide only one connection from their office
Router to a service provider edge router. BSNL has tied up with various Networking solution
providers to Provide end-to-end solution to its valued customers, including Customer End (CE)
routers and other networking components. What advantages does MPLS VPN have over other
Technologies BSNL's primary objectives in setting up the
2.1 BGP/MPLS VPN Network:
Provide a diversified range of services (Layer 2, Layer 3 and Dialup VPNs) to meet the
requirements of the entire spectrum of Customers from Small and Medium to Large business
enterprises And financial institutions. Make the service very simple for customers to use even

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if they Lack experience in IP routing. Make the service very scalable and flexible to facilitate
large-scale Deployment. Provide a reliable and amenable service, offering SLA to customers
Capable of meeting a wide range of customer requirements, including security, quality of
Service (QOS) and any-to-any Connectivity. Capable of offering fully managed services to
customers. Allow BSNL to introduce additional services such as bandwidth on
Demand etc. over the same network.
2.2 What is a MPLS VPN anyway?
This paper is about a new technology, MPLS VPN that is being offered by Service
providers to compete with Frame Relay and ATM networks. When accompany wants to
connect its geographically different sites they don’t have to Purchase a Frame Relay circuit, or
purchase an ATM circuit, or lease a dedicated Telco line. They developed a new Protocol that
is called MPLS; it was actually based on Cisco’s proprietary tag switching protocol. MPLS
stands for Multi-Protocol Label Switching. It was a Protocol that was developed to help speed
up the process of routing packets on The Internet. The MPLS architecture is defined in RFC
3031.Every router then chooses its own Next hop for the packet based on the packet's header
and the routing algorithm. Routers will assign each packet into a set of "Forwarding
Equivalence Classes (FECs)"(2). They will then map each FEC to a next hop.AS that exchange
routing information. If you go to the following URL you can look at the major players United
States Internet backbones; http://www.nthelp.com/maps.htm.The people at the Internet
Engineering Task Force (IETF) decided something had to be done to speed up the process of
routing packets on the Internet or the Whole thing was going to come to a screeching halt. They
can now go to their Internet service provider and purchase amps VPN to connect their
geographically different sites. This s paper will give basic understanding of how a MPLS VPN
works. First let’s start with a little background to explain why the need for MPLS. As forth
need for a VPN, there is plenty of reading material in the SANS reading room On VPN
technology. You see the Internet has gotten very big with Internet backbone routers having to
Hold 100,000+ BGP routes (1).Border Gateway Protocol version 4 (BGP4) is Defector routing
protocol of the Internet; it is an exterior routing protocol used to Exchange routing information
between Autonomous Systems (AS).

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CHAPTER 3
3. WLL SYSTEM OVERVIEW
Wireless local loop (WLL), is the use of a wireless Communications link as the “last
mile / first mile" connection for delivering plain old telephone service (POTS) or Internet
access (Marketed under the term "broadband") to telecommunications Customers. Various
types of WLL systems and technologies exist. Other terms for this type of access include
Broadband Wireless Access (BWA), Radio in the Loop (RITL), Fixed-Radio Access (FRA),
Fixed Wireless Access (FWA) and Metro Wireless (MW).Definition of fixed wireless service
Fixed Wireless Terminal (FWT) units differ from conventional Mobile terminal units operating
within cellular networks – such sags – in that a fixed wireless terminal or desk phone will be
Limited to an almost permanent location with almost no roaming Abilities. WLL and FWT are
generic terms for radio based Telecommunications technologies and the respective devices
which can be implemented using a number of different wireless and radio technologies.
Wireless local loop services are segmented into a number of Broad market and deployment
groups. Services are split between Licensed – commonly used by carriers and Telco’s – and
unlicensed services more commonly deployed by home users and Wireless ISPs (WISPs).
Fig- 3.1 WLL SYSTEM OVERVIEW
[Citation needed]Licensed points-to-point microwave services licensed microwave services
have been used since the 1950s to Transmit very large amounts of data. The AT&T Long Lines
coast To coast backbone in the USA was largely carried over a chain of Microwave towers.
These systems have been largely using 3700–4200 MHz and 5000–5200 MHz the 5 GHz band

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was even known as the "common carrier" band. This service typically was prohibitively
expensive to be used for local loops, and was used for backbone networks. In the 1980s and
1990s it flourished under the growth of cell towers. This growth spurred research in this area,
and as the cost continues to decline, it is being used as an alternative to T-1, T-3, and fibre
connectivity
These Mac Layers typically used a 15–20 MHz channel using Direct Sequence Spread
Spectrum and BPSK, CCK and QPSK for modulation. These devices all describe the customer
premises wireless System as the Subscriber Unit (SU), and the operator transmitter delivering
the last mile local loop services as the Access Point (AP). 802.10 uses the terms AP and STA
Mobile:
CDMA (USA).
TDMA (USA).
GSM (ITU – Worldwide).
UMTS 3rd Generation (World).
Personal Handy-phone System (PHS in Japan, PAS/Xiaolingtong in China)
Fixed or local area network: DECT, for local loop LMDS EEE 802.10, originally designed for
short range mobile Internet and network access service, it has emerged as the Fact standard for
Wireless Local Loop. IMAX or IEEE 802.15 may become the dominant medium for wireless
local loop. Currently more operators are running On the 802.10 MAC at 2 and 5 GHz. 802.15
is unlikely to Outperform 802.10 until at least late 2008. Intel is promoting this standard, while
Atheros and Broadcom are still focused largely on 802.10.

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CHAPTER 4
4. VARIOUS TYPES OF TRANSMISSION SYSTEM IN BSNL
Whereas Phone Mechanics would predominantly work in the technology areas, they
would also be required to perform the duties which are being presently performed by the above
cadres who will since be phased out in due course of time. The duties of the Phone Mechanics
to be performed under overall guidance of TTAs/JTOs are given below.
4.1 Overhead lines
1. General: Prepare diagrams store lists, maintain muster roll, keep records. Diaries climb poles
without help of any appliance.
2. Construction: Assemble and erect poles, stays, bracket struts etc., erection, leveling and
jointing of wires and associated line construction work, lay cables, run construction parties
3. Maintenance: Patrolling lines, giving tests for localizations of faults, rectification of faults,
attending to subscriber’s loops, run maintenance parties.
4. General: Repair of faulty cords, keys, jacks, lamps, and lam strips, fitting and replacing
protective devices including GD tubes, installation and maintenance of primary and secondary
batteries and power plants, testing instruments, firefighting equipment cleaning of equipment.
5. Wiring: Fitting and wiring in subscriber offices, paying, fencing, lacing, tagging, termination
and soldering/ wrapping/IDC Termination of switch board cables and jumper at MDF, IDF,
TDF and Cabinets, Pillars and DPs, wiring and testing of trunk and local boards, PBX, PABX
boards, all auto and electronic exchange, carrier and VFT interstice Coaxial, microwave
stations, telegraph offices and all electrical installations.
5. Fault Rectification: Faults in manual switch- boards, Rural Exchanges including Electronic
Exchanges, faults in Telephone instruments including plan instruments, Morse sets and
associated equipment’s in Telegraph office.
7. General: Preparing diagrams, pressurization of cables installations of gas pressure system,
alarm and Schrader valves, gas barrier etc., feed gas and take pressure readings, be conversant
with color codes of cables.

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8. Maintenance and construction: Testing of cables laying and jointing underground cables of
all types, making through schedule, branch vertical and the joints, termination of UG cables,
switch board cables on MDF, DP and Cabinets, installation and fitting of loading coils, testing,
localization and rectification of cable faults, retrieval of faulty pairs, use of test instruments,
including pulse echo tester, joining of optic fiber / coaxial cables, building, of pairs by
rearrangement in cabinets / pillars.
9. Miscellaneous: Assisting TTA, JTO and other superiors in maintenance, constructing and
installation of switching and transmission equipment.
10. Any other duties assigned by his seniors.
4.2 TTA (Transmission)
1. Installation, maintenance and testing types of open – wire carrier, VFT, Interstice, coaxial,
MARR, PCM, optical fiber, microwave, satellite and other type of transmission systems with
all associated equipment’s.
2. Installation and maintenance of wireless equipment, transmitters and receivers, Morse sets
masts, aerials etc.
3. Sending, receiving and monitoring traffic on wireless links of all type, pass massages on
phone, operate auto transmitters of for weather and traffic broadcasts as well as ship to shore

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CHAPTER 5
5. OFC SYSTEM (OPTICAL FIBER SYSTEM
A powerful coherent light beam together with the Possibility of modulation at high
frequencies was the key feature of LASER.
Kao and Hock ham proposed the transmission of Information via dielectric waveguides or
optical fibre cables Fabricated from glass almost simultaneously in 1955. In the earlier Stage
Fig- 5.1 OPTICAL FIBER SYSTEM
Optical fibres exhibited very high attenuation (almost 1000DB/km) which was incomparable
with coaxial cables having Attenuation of around 5 to 10dB/km. Nevertheless, within ten years
Optical fibre losses were reduced to below 5dB/km and suitable Low loss jointing techniques
were perfected as well. Parallel with The development of the optical fibres other essential
optical Components like semiconductor optical sources (i.e. injection Lasers and LEDs) and
detectors (i.e. photodiodes and Phototransistors) were also going through rigorous research
Process.
Primarily the semiconductor LASERs exhibited very short Lifetime of at most a few
hours but by 1973 and 1977 lifetimes Greater than 1000 hr. and 7000 hr. respectively were
obtained through advanced device structure. The first generation optical fibre links operated at
around 850 NM Range. Existing Gas based optical sources, silicon photo detectors, and
multimode fibres were used in these links and quiet understandably they suffered from
intermodal dispersion and fibre Losses. Systems operating at 1550nm provided lowest
attenuation and these links routinely carry traffic at around2.5Gb/s over 90 km repeater less
distance. The introduction of Optical amplifiers like Erbium-doped fibre amplifiers (EDFA)
and Praseodymium-doped fibre amplifiers (PDFA) had a major thrust to Fibre transmission

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capacity. The use of Wavelength Division Multiplexing along with EDFA proved to be a real
boost in fibre Capacity. Hence developments in fibre technology have been carried out rapidly
over recent years. Glass material for even Longer wavelength operation in the mid-infrared
(2000 to 5000nm) and far-infrared (8000 to 12000nm) regions have been developed.
Types of OpticalFibbers:
5.1Step index fibres:
If the refractive index profile of a fibre makes a step change at the Core cladding interface
then it is known as step index fibre the core Diameter of which is around 50µm. Some physical
parameters like
Relative refractive index, index difference, core radius etc. Determines the maximum
number of guided modes possible in a Multimode fibre. A single mode fibre has a core diameter
of the Order of 2 to 10µm It has the distinct advantage of low intermodal Dispersion over
multimode step index fibre. On the other hand Multimode step index fibres allow the use of
spatially incoherent Optical sources.
5.2 Graded index fibres:
The graded index fibres have decreasing core index n(r) with radial Distance from a maximum
value of n1 at the axis to a constant Value n2 beyond the core radius a in the cladding. The
graded index fibre gives best results for multimode Optical propagation for parabolic
refractive index profile. Due to This special kind of refractive index profile multimode graded
index Fibres exhibit less intermodal dispersion than its counterpart i.e. Multimode step index
fibre

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CHAPTER 6
6. BROADBAND TECHNOLOGY
The term broadband commonly refers to high-speed Internet Access that is always on
and faster than the traditional dial-up Access. Broadband includes several high-speed
transmission Technologies such as Digital Subscriber Line (DSL) Cable Modem Fibber
Wireless Satellite Broadband over Power lines (BPL) The broadband technology you choose
will depend on a number of Factors. These may include whether you are located in an urban or
rural area, how broadband Internet access is packaged. Made by Ravi Kant with other Services
(such as voice telephone and home entertainment), price, and availability. Digital Subscriber
Line (DSL)DSL is a wire line transmission technology that transmits data faster Over
traditional copper telephone lines already installed to homes And businesses. DSL-based
broadband provides transmission Speeds ranging from several hundred Kbps to millions of bits
per Second (Mbps). The availability and speed of your DSL service may depend on the distance
from your home or business to the closest Telephone company facility. The following are types
of DSL transmission technologies: Asymmetrical Digital Subscriber Line (ADSL) – Used
primeResidential customers, such as Internet surfers, who receive a lot of Data but do not send
much. ADSL typically provides faster speed in the downstream direction than the upstream
directionADSL allows faster downstream data transmission over the same line used to Provide
voice service, without disrupting regular telephone calls on that line.
Fig-6.1 BROADBAND TECHNOLOGY

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CHAPTER 7
7. SOFTWARES USED IN BSNL
The following software packagesare usedin BSNL:-
 Richer Billing Package
 Scanjet
 Do soft
 Billing and Customer Care System (BCCS) for Mobile Billing
 Customer Relationship Management (CRM)
 Sancharsoft
 Inventory Management Package
 Fleet Management System
 Management Information System (MIS)
 CDR Based Convergent Billing and Customer Care System
 Call Centre Applications
 HR Package
 ERP
 BBS (Balanced Business Scorecards
 15 Public Grievance Management System (PGMS)

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CHAPTER 8
8. CDMA CONCEPTS
Introduction to Cellular Communication:
To provide wireless communication access to subscribers we need a pair of RF channels
per active call. In a large city with several thousand subscribers’ number of channels required
would be so large that they cannot be accommodated on one site. Also there is a limit to
availability of spectrum. If an operator’s get a 5 MHz band, then he has only 25 channels to
use with 25 channels loaded at one site he can offer cellular service to 2000 subscribers at most.
To overcome this limitation, you have to create zones of coverage, w which are called as cells.
Fig -8.1 CDMA SYSTEM
8.1 Cellular Structure:
Cells in cellular system are hexagons. The actual cell covered by a base station takes a very
different shape depending upon the terrain obstructions and transmitting antenna characteristics.
The cells are of different sizes and shapes to cover a den sly populated area, smaller cells are used.
Where a large cells cover a low subscriber density areas. On the highways and main roads cell size
8.2 Code Division Multiplexing Access:-
The CDMA standard allows up to 51 simultaneous users in one 1.2288 MHz channel. By
processing each voice packet with two PN codes. It is virtually impossible to monitor a CDMA
conversation or fraudulently access ESNs, PINs or credit card numbers.

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Though there are 54 Walsh codes available to differentiate call and theoretical limits are
around 40 calls. The operational limitations and quality issues will reduce the maximum number
of calls somewhat below this value.
8.3 Channelization Methods
• The band used in CDMA is 824 MHz to 894 MHz (50 MHz + 20 MHz separation)
• Frequency channel is divided into code channels
• 1.25 MHz of FDMA channel is divided into 54 code channels.
8.4 CDMA is a Code Division Multiple Access
• Spread spectrum technique
• Multiple users share the same frequency in one cell
• Same frequency in all the cells
• Takes advantage of Multipath

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CHAPTER 9
9. GLOBAL SYSTEM FOR MOBILE COMMUNICATION
(GSM)
The GSM Association is a unique organization, with a truly global reach, offering a full
range of business and technical services to its members. Now as the wireless family unfolds
the association is deriving forward its vision of seamless, limitless, world of wireless
communication.
Fig-9.1 GLOBAL SYSTEM FOR MOBILE COMMUNICATION
Throughout the evolution of cellular telecommunications, various systems have been
developed without the benefit of standardized specifications. This presented many problems
directly related to compatibility, especially with the development of digital radio technology.
The GSM standard is intended to address these problems. Global system for mobile
communication (GSM) is a globally accepted standard for digital cellular communication.
GSM is the name of a standardization group established in 1982 to create a common European
mobile telephone standard that would formulae the specifications for a pan-European mobile
cellular radio system operating at 900 MHz it is estimated that many country outside of Europe
will join the GSM partner

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CHAPTER 10
10. C-DOT MAX-XL
C-DOT DSS MAX is a universal digital switch which can be configured for different
applications as local, transit, or integrated local and transit switch. High traffic/load handling
capacity up to 8,00,000 BHCA with termination capacity of 40,000 Lines as Local Exchange
or 15,000 trunks as Trunk Automatic Exchange, the C-DOT DSS family is ideally placed to
meet the different requirements of any integrated digital network.
The design of C-DOTDSS MAX has envisaged a family concept. The advantages of family
concept are standardized components, commonality in hardware, documentation, training,
installation and field support for all products and minimization of inventory of spares. In fact
this modular design has been consciously achieved by employing appropriate hardware,
software, and equipment practices.
Fig-10.1 C-DOTMAX-XL
The equipment practices provide modular packaging. Common cards and advanced
components have been used in the system hardware in order to reduce the number and type of
cards. Standard cards, racks, frames, cabinets and distribution frames are used which facilitate
flexible system growth. Interconnection technology has been standardized at all levels of
equipment packaging. All these features, together with ruggedized design, make C-DOT DSS
MAX easy to maintain and highly reliable. Another important feature of the design is the
provision of both local and centralized operation and maintenance. Beginning with local
operation and maintenance, with the installation of similar digital switches in the network,
centralized operation and maintenance will provide maintenance and administration services

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very economically. All these services are provided through a si1mple, interactive man-machine
interface.
10.1 BASIC GROWTH/BUILDING MODULES
C-DOT DSS MAX exchanges can be configured using four basic modules
 Base Module
 Central Module
 Administrative Module
 Input Output Module
10.2 BASE MODULE
The Base Module (BM) is the basic growth unit of the system. It interfaces the external
world to the switch. The interfaces may be subscriber lines, analogy and digital trunks, CCM
and PBX lines. Each Base Module can interface up to 2024 terminations. The number of Base
Modules directly corresponds to the exchange size. It carries out majority of call processing
functions and, in a small-exchange application, it also carries out operation and maintenance
functions with the help of the Input Output Module. In Single Base Module (SBM) exchange
configuration, the Base Module acts as an independent switching system and provides
connections to 1500 lines and 128 trunks. In such a configuration, the Base Module directly
interfaces with the Input Output Module for bulk data storage, operations and maintenance
functions. Clock and synchronization is provided by a source within the Base Module. It is a
very useful application for small urban and rural environments.With minimum modifications
in hardware through only one type of card, a Base Module can be remotely located as a Remote
Switch Unit (RSU), parented to the main exchange using PCM links.
10.3 CENTRAL MODULE
Central Module (CM) consists of a message switch and a space switch to provide inter-
module communication and perform voice and data switching between Base Modules. It
provides control message communication between any two Base Modules, and between Base
Modules and Administrative Module for operation and maintenance functions. It also provides
clock and synchronization on a centralized basis.
10.4 ADMINISTRATIVE MODULE

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Administrative Module (AM) performs system-level resource allocation and processing
function on a centralized basis. It performs all the memory and time intensive call processing
support functions and also administration and maintenance functions. It communicates with
the Base Module via the Central Module. It supports the Input Output Module for providing
man- machine interface. It also supports the Alarm Display Panel for the audio-visual
indication of faults in the system.
10.5 INPUT OUTPUT MODULE (I/OM)
Input, Output Module (IOM) consists of duplicated Input Output Processor (IOP). The
Input Output Processor (IOP) is a general-purpose computer with UNIX Operating System. It
is used as the front-end processor in C-DOT DSS. It handles all the input and output functions
in C-DOT DSS. The IOP is connected to AP/BP via HDLC links. During normal operation,
two IOP’s interconnected by a HDLC link, operate in a duplex configuration. Working as front-
end processor, it provides initial code down load to the subsystems, man machine interface and
data storage for billing and other administrative information.
Fig-10.2 C-DOTMAX-XL-INPUT/OUTPUT MODUL
IOP interfaces various secondary storage devices like' disk drives, cartridge tape drive and
floppy drive. It supports printers and up to 8 serial ports for video display units which are used
for man- machine communication interface. All the bulk data processing and storage is done
in this module
Thus, a C-DOT DSS exchange, depending upon its size and application, consists of Base
Modules (maximum 32), Central Module, Administrative Module, Input/output Module and

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CHAPTER 11
11.CONCLUSION
A student gets theoretical knowledge from classroom and gets practical knowledge
from industrial training. When these two aspects of theoretical knowledge and practical
experience together then a student is full equipped to secure his best.
In conducting the project study in an industry, students get exposed and have knowledge of
real situation in the work field and gains experience from them. The object of the summer
training cum project is to provide an opportunity to experience the practical aspect of
Technology in any organization. It provides a chance to get the feel of the organization and its
function.
I have privilege taking my practical training at “BSNL “where we know about
communication. Broadband, WLL system, OFC system, and transmission system.