training report on telecommunications bsnl

8/11/2019 Training report on telecommunications BSNL

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SEMINAR ON INDUSTRIAL TRAINING(JUNE-JULY, 2014)

Telecommunication

Submitted by

MALVIKA

11113163

under the Guidance of

Mr. Anand Prakash Singh

(DT at BSNL, Patna)

Discipline of Electronics and Communication

Lovely Professional University, Phagwara

June-July, 2014


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DECLARATION

I hereby declare that I have completed my six weeks summer training at BSNL,

PATNA from 16 June to 25 July under the guidance of Mr Anand Prakash Singh

I have worked with full dedication during these six weeks and my learning outcomes

fulfill the requirements of training.

(Signature of Student)

Name of student: Malvika

Registration Number: 11113163

Date: ________________


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Acknowledgement

I acknowledge my gratitude and thank to all the well knowledge persons for giving me such

opportunity to avail all the best facilities available at this telecom centre through which I have

gained knowledge thinking so as too just in the environment suitable for harmonic

adjustment. I am grateful to the following persons for various help rendered by them during

the training period.

Mr Dinesh Kumar (DT)

Mr Neeraj Kumar (JTO)

Finally a deep thanks to Mr Vijay Kumar (TTA) and Mr Deepak Gandhi (TTA).

Last but not the least I thank my family members for their constant encouragement.


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BHARAT SANCHAR NIGAM LIMITED

(BSNL)

Bharat Sanchar Nigam Limited (abbreviated BSNL ) is an Indian State-owned enterprise in

Telecommunication. The Headquarter is situated in New Delhi, India.

Mr R.K. Upadhyay is the present chairman and MD of BSNL. The Owner of BSNL is

Government of India. Number of Employees on 27 February 2013 was 254,499.

The Website is: - www.bsnl.co.in

It is the largest provider of fixed telephony (landline) and fourth largest Mobile telephony

provider in India, and is also provides Broadband service. Due to intense competition in

Telecommunication Sector Companys revenue and market share plunged into heavy losses. BSNL is Indias oldest and largest communication service (CSP ). It had a customer base of

95 million as of June 2011. It has footprints throughout India except for the metropolitan

cities of Mumbai and New Delhi, Which are managed by Mahanagar Telephone Nigam

(MTNL).

Services:-

BSNL provides almost every telecom service in India. Following are the main telecomservices provided by BSNL:

Universal Telecom Services : Fixed wire line services and landline in local loop

(WLL) using CDMA Technology. As of 30 June 2010, BSNL had 75% market share

of fixed lines.

Cellular Mobile Telephone Services : BSNL is major provider of Cellular Mobile

Telephone services using GSM platform under the brand name Cellone & Excel

(BSNL Mobile). As of 30 June 2010 BSNL has 13.50% share of mobile telephony inthe country..

Internet : BSNL provides Internet access services through dial-up connection (as

Sancharnet through 2009) as Prepaid, NetOne as Post-paid and ADSL broadband as

BSNL Broadband BSNL held 55.76% of the market share with reported subscriber

base of 9.19 million Internet subscribers with 7.79% of growth at the end of March

2010.

Intelligent Network (IN) : BSNL offers value-added services, such as Free Phone

Service (FPH), India Telephone Card (Prepaid card), Account Card Calling (ACC),
https://en.wikipedia.org/wiki/File:BSNL_Logo.svg


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Virtual Private Network (VPN), Tele-voting, Premium Rae Service (PRM), Universal

Access Number (UAN).

3G :BSNL offers the '3G' or the'3rd Generation' services which includes facilities like

video calling, mobile broadband, live TV, 3G Video portal, streaming services like

online full length movies and video on demand etc.

Helpdesk : BSNL's Helpdesk (Helpdesk) provide help desk support to their customers

for their services.

WiMax : BSNL has introduced India's first 4th Generation High-Speed Wireless

Broadband Access Technology with the minimum speed of 256kbit/s. The focus of

this service is mainly rural customer where the wired broadband facility is not

available.

GSM TECHNOLOGY

(GSM- GLOBAL SYSTEM FOR MOBILE COMMUNICATION)

Principle of Mobile Communication

Multiple Access methodology

The technique of dynamically sharing the finite limited radio spectrum by multiple users is

called Multiple Access Technique.

Generally there are three different types of multiple access technologies. They are

Frequency Division Multiple Access (FDMA) Time Division Multiple Access (TDMA) Code Division multiple Access (CDMA)

Frequency Division Multiple Access (FDMA):

FDMA is a familiar method of allocating bandwidth, where a base station is allowed

transmit on one or more number of preassigned carrier frequencies and a mobile unit

transmits on corresponding reverse channels.

Time Division Multiple Access (TDMA):

In a TDMA system each channel is split up into time segments, and a transmitter is given

exclusive use of one or more channels only during a particular time period.

Duplexing and Multiple Access Techniques in use:

No Name of System Multiple Access Duplexing

1 GSM FDMA-TDMA FDD

2 CDMA CDMA FDD


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FREQUENCY ALLOCATION :

Two frequency bands have been allocated for the GSM system:

The band 890-915 MHz and 1710-1785 MHz has been allocated for the uplink

direction (transmitting from the mobile station to the base station).

The band 935-960 MHz and 1805-1880 MHz has been allocated for the downlink

direction (transmitting from the base station to the mobile station).

ARCHITECTURE OF THE GSM NETWORK

Subsystems and network elements in GSM

The GSM network is called Public Land Mobile Network (PLMN). It is organised in three

subsystems:

Base Station Subsystem (BSS) Network Switching Subsystem (NSS) Network Management Subsystem (NMS)

1. Base Station Subsystem (BSS)

The Base Station Subsystem is responsible for managing the radio network, and it is

controlled by an MSC. Typically, one MSC contains several BSSs. A BSS itself may cover a

considerably large geographical area consisting of many cells (a cell refers to an area covered

by one or more frequency resources). The BSS consists of the following elements:

OMC

MSCBSC HLR

A

MS

Other

MSCs

BTS AUC

Other

Networks

EIR

Other

MSCs

VLRsVLR

BSS

B

C

D

EF

G

Un Abis


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BSC Base Station Controller BTS Base Transceiver Station TRAU Transcoder and Rate Adaptation Unit (often referred to as TC (Transcoder))

Radio path control

In the GSM network, the Base Station Subsystem (BSS) is the part of the network taking care

of radio resources, that is, radio channel allocation and quality of the radio connection .

2. Network Switching Subsystem (NSS)

The Network Switching Subsystem (NSS) contains the network elements MSC, GMSC,

VLR, HLR, AC and EIR .

The main functions of NSS are:

Call control : This identifies the subscriber, establishes a call, and clears the connection after

the conversation is over.


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Charging : This collects the charging information about a call (the numbers of the caller and

the called subscriber, the time and type of the transaction, etc.) and transfers it to the Billing

Centre.

Mobility management : This maintains information about the subscriber's location.

Signalling : This applies to interfaces with the BSS and PSTN.

Subscriber data handling : This is the permanent data storage in the HLR and temporary

storage of relevant data in the VLR.

Mobile Switching Centre (MSC)

Mobile-services Switching Center (MSC) performs the switching functions for all mobile

stations located in the geographic area covered by its assigned BSSs. Functions performed

include interfacing with the Public Switched Telephone Network (PSTN) as well as with the

other MSCs and other system entities, such as the HLR, in the PLMN.

Functions of the MSC include:

Call handling that copes with mobile nature of subscribers (e.g., paging) Management of required logical radio-link channel during calls Management of MSC-BSS signalling protocol Handling location registration and ensuring interworking between Mobile Station and

VLR

Control of inter-BSS and inter-MSC handovers Acting as a gateway MSC to interrogate the HLR Exchange of signalling information with other system entities Standard functions of a local exchange switch in the fixed network (example: charging)

Gateway Mobile services Switching Centre (GMSC)

The GMSC is responsible for the same tasks as the MSC, except for paging. It is needed in

case of mobile terminated calls. In fixed networks, a call is established to the local exchange,to which the telephone is connected to. But in GSM, the MSC, which is serving the MS,

changes with the subscribers mobility. Therefore, in a mobile terminated call, the call is set

up to a well defined exchange in the subscribers home PLMN. This exchange is called

GMSC. The GMSC than interacts with a database called Home Location Register, which

holds the information about the MSC, which is currently serving the MS. The process of

requesting location information from the HLR is called HLR Interrogation. Given the

information about the serving MSC, the GMSC then continues the call establishment process.

In many real life implementations, the MSC functionality and the GMSC functionality are


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implemented in the same equipment, which is then just called MSC. Many operators use

GMSCs for breakout to external networks such as PSTNs.

Home Location Register (HLR)

The Home Location Register (HLR) contains the identities of mobile subscribers (calledInternational Mobile Subscriber Identities or IMSIs), their service parameters, and their

location information.

The HLR contains:

Identity of mobile subscriber ISDN directory number of mobile station Subscription information on teleservices and bearer services

Service restrictions (if any) Supplementary services Location information for call routing

Visitor Location Register (VLR)

The Visitor Location Register (VLR) contains the subscriber parameters and location

information for all mobile subscribers currently located in the geographical area (i.e., cells)

controlled by that VLR.

In summary, the VLR contains: Identity of mobile subscriber Any temporary mobile subscriber identity ISDN directory number of mobile A directory number to route calls to a roaming station Location area where the mobile station is registered Copy of (part of) the subscriber data from the HLR

Equipment Identity Register (EIR) The Equipment Identity Register (EIR) is accessed during the equipment validation

procedure

when a mobile station accesses the system. It contains the identity of mobile station equipment

(called International Mobile Station Equipment Identity or IMEI) which may be valid, suspect,

or known to be fraudulent.

This contains:


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White or Valid list - List of valid MS equipment identitiesGrey or Monitored list - List of

suspected mobiles under observation

Black or prohibited list - List of mobiles for which service is barred.

Authentication Center (AUC)The Authentication Center (AUC):

Contains subscriber authentication data called Authentication Keys (Ki) Generates security related parameters needed to authorize service using Ki Generates unique data pattern called a Cipher Key (Kc) needed for encrypting user

speech and data

3.OPERATION AND MAINTENANCE CENTER (OMC)

The Operations and Maintenance Center (OMC) is the centralized maintenance anddiagnostic heart of the Base Station System (BSS). It allows the network provider to

operate,administer, and monitor the functioning of the BSS.

4.OTHER NETWORK ELEMENTS

Other optional network elements that the MSC can interface include:

Billing Center:

Each MSC writes call accounting records to local disk memory. The Billing Center

periodically polls the disk records of each MSC to collect the billing data for the PLMN.Service Center:

The Service Center interfaces with the MSCs to provide special services, such as the Short

Message Service (SMS), to mobile subscribers in the PLMN.

The Billing Center and Service Center are not a basic part of the GSM system.

GPRS (General Packet Radio Service)

GPRS uses a packet-based switching technique, which will enhance GSM dataservices significantly, especially for bursty Internet/intranet traffic.

Some application examples:

Bus, train, airline real-time information Locating restaurants and other entertainment venues based on current Location Lottery E-commerce

Banking


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E-mail Web browsing

The main advantages of GPRS for users:

Instant access to data as if connected to an office LAN

Charging based on amount of data transferred (not the time connected) Higher transmission speeds

In circuit switching, each time a connection is required between two points, a link between

the two points is established and the needed resources are reserved for the use of that single

call for the complete duration of the call.

In packet switching, the data to be transferred is divided up into packets, which are then sent

through the network and re-assembled at the receiving end.

Evolution from GSM to 3G

CDMA TECHNOLOGY

In CDMA ( Code Division Multiple Access) all information of the customers are on the

same frequency. Each information of customer is separated by a digital code. Digital codes

separates information to stop interference. It provide soft hand off for the mobile crossing

from one cell to another by combining the signals from both the cells in the transition areas.

This improves the performance of the network and call dropping problemgets over. In

CDMA many customers can talk at the same time.


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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 deployment 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. Fibre 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.

The salient features of a typical CDMA system are as follows:

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

Duplexing Mehtod: 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.

Different Codes used in CDMA

Walsh Code:

In CDMA the traffic channels are separated by unique Walsh code. All such codes are

orthogonal to each other. The individual subscriber can start communication using one of

these codes. These codes are traffic channel codes and are used for orthogonal spreading of


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the information in the entire bandwidth. Orthogonality provides nearly perfect isolation

between the multiple signals transmitted by the base station.

The basic concept behind creation of the code is as follows:

(a) Repeat the function right

(b) Repeat the function below

(c) Invert function (diagonally)

0 ----- 0 0 -------- 0 0 0 0

0 1 0 1 0 1

0 0 1 1

0 1 1 0

Long Code:

The long pseudo random noise (PN) sequence is based on 2 42 characteristic polynomial. With

this long code the data in the forward direction (Base to Mobile) is scrambled. The PN codes

are generated using linear shift registers. The long code is unique for the subscribers and is

known as users address mask.

Short Code:

The short pseudo random noise (PN) sequence is based on 2 15 characteristic polynomial. This

short code differentiates the cells & the sectors in a cell. It also consists of codes for I & Q

channel feeding the modulator.

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).

RGMTT Presenta t ion

Um E

Abis A

Q C

B

N H

MS

BT S B SC

PSTNM SC

M S C/SSP VLR

HLR AUCMC

D

MCM

MSS

BSS

Ai

Architecture of CDMA MSC Based WLL system


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Conclusion:

Hence use of common frequency, multipath rake receiver, power control & variable bit rate

vocoding and soft hand-off features of CDMA give us the benefits of no frequency planning,

larger capacity, flexibility alongwith high performance quality.

BROAD BAND

Broadband is often called high-speed Internet, because it usually has a high rate of data

transmission. In general, any connection to the customer of 256 kbit/s or more is considered

broadband.

BROADBAND AND DIAL-UP SERVICE:

Broadband service provides higher speed of data transmission Allows more contentto be carried through the transmission pipeline.

Broadband provides access to the highest quality Internet services streaming media,

VoIP (Internet phone), gaming and interactive services. Many of these current and

newly developing services require the transfer of large amounts of data which may

not be technically feasible with dial-up service. Therefore, broadband service may be

increasingly necessary to access the full range of services and opportunities that the

Internet can offer.

Broadband is always on does not block phone lines and no need to reconnect to

network after logging off.

Less delay in transmission of content when using broadband.

IMPORTANCE OF BROADBAND:

Broadband can provide you with the technical capability to access a wide range of resources,

services and products that can enhance your life in a variety of ways. These resources,

services and products include,

Education, Culture, & Entertainment

o Broadband can overcome geographical and financial barriers to provide access to a

wide range of educational, cultural and recreational opportunities and resources.

Tele-health & Telemedicine

o Broadband can facilitate provision of medical care to unserved and underserved

populations through remote diagnosis, treatment, monitoring and consultations with

specialists.

Economic Development/E-Commerce


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o Broadband can promote economic development and revitalization through electronic

commerce (e-commerce) by:

Creating new jobs and attracting new industries.

Providing access to regional, national and worldwide markets.

Electronic Government (E-Government)

o Electronic government can help streamline peoples interaction with government

agencies and provide information about government policies, procedures, benefits and

programs.

Public Safety and Homeland Security

o Broadband can help protect the public by facilitating and promoting public safety

information and procedures, including, but not limited to:

Early warning/public alert systems and disaster preparation programs.

Remote security monitoring and real time security background checks.

Backup systems for public safety communications networks.

Broadband Communications Services

o Broadband provides access to new telecommunications technologies such as Voice

Over Internet Protocol (VoIP) allowing voice communication using the Internet.

Communications Services for People With Disabilities

Broadband permits users of Telecommunications Relay Services (TRS) to use Video Relay

Services (VRS) to communicate more easily, quickly and expressively with voice telephone

users.

BROAD BAND SERVICES

Broadband refers to a connection that has capacity to transmit large amount of data at

high speed. Presently a connection having download speeds of 256 kbps or more is classified

as broadband. When connected to the Internet broadband connection allows surfing or

downloading much faster than a dial-up or any other narrowband connections. BSNL offers 2

Mbps minimum download speed for its Broadband connections.

Requirement for providing Broad Band connection

1. Personal Computer

2. ADSL Modem

3. Land Line Connection

4.

Splitter for separating telephone from Personal computer.


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Services available through Broadband

High speed Internet Access : This is the always-on Internet access service with speed

ranging from 256 kbps to 8 Mbps.

Bandwidth on Demand : This will facilitate customer to change bandwidth as per his

/ her requirement. For example a customer with 256 kbps can change to 1 Mbps

during the video Conferencing session.

Multicasting : This is to provide video multicast services, video-on-demand etc. for

application in distance education, telemedicine etc.

Billing: To provide a means to bill for the aforesaid services by either time-based or

volume-based billing. It shall provide the customer with the option to select the

services through web server To provide both pre-paid and post paid broadband

services

IP Telephony Messaging: plain and feature rich, Multi-site MPLS VPN with Quality of Service (QoS) guarantees. Wi -Fi Web hosting & web co-location. Lease line service

Dial VPN Service : This service allows remote users to access their private network

securely over the NIB-II infrastructure.

Video and Audio Conferencing : Content based Services : Like Video on Demand, Interactive Gaming, Live and time

shifted TV

Video on Demand: Customers can view any movie of their choice from a pool of

movies stored in a central server. The movies can be viewed either on a TV or a PC.

Audio on Demand: It is a similar service where person can listen to any music of hischoice.

TV channels through broadband connection: The TV channels may be available

in the broadband connection. In fact, there may be other new channels, particularly

the educational and scientific channels, depending on demand. Additional equipments

required in the customer's premises are

Set Top Box (STB) - The STB converts the digital IP based signal to a form

compatible with the TV set.


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PC and TV

Miscellaneous Applications of Broadband :

Video-on-Demand

Interactive Games Share market dealing & personal banking News, travel & leisure information Music/Movie Download Chat rooms & newsgroups E-mail & instant messaging

Personal websites and online magazinesWIRELESS-FIDELITY (WI-FI)

Wi-Fi is a registered trademark by the Wi-Fi Alliance. . It is Short form for W ireless-

Fi delity and is meant to generically refer to any type of 802.11 network, whether

802.11b, 802.11a, dual -band, etc. 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 ofinstallation. 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.

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 toLaptops, 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


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devices per Access Point (AP) depending on the network 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.

Benefits of Wi-Fi:

In a Wi-Fi users can access shared information without looking for a place to plug in, andnetwork managers can set up or augment networks without installing or moving wires. Wi-Fi

offers the following productivity, conveniences, and cost advantages over traditional wired

networks:

Mobility: Wi-Fi systems can provide LAN users with access to real-time information

anywhere in their organization. This mobility supports productivity and service

opportunities not possible with wired networks.

Installation Speed and Simplicity: Installing a Wi-Fi system can be fast and easyand can eliminate the need to pull cable through walls and ceilings.

Installation Flexibility: Wireless technology allows the network to go where wire

cannot go.

Reduced Cost-of-Ownership: While the initial investment required for Wi-Fi

hardware can be higher than the cost of wired LAN hardware, overall installation

expenses and life-cycle costs can be significantly lower. Long-term cost benefits are

greatest in dynamic environments requiring frequent moves, adds, and changes.


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Scalability: Wi-Fi systems can be configured in a variety of topologies to meet the

needs of specific applications and installations. Configurations are easily changed and

range from peer-to-peer networks suitable for a small number of users to full

infrastructure networks of thousands of users that allows roaming over a broad area.

It offers much high speed upto 54 Mbps which is very much greater than other

wireless access technologies like CORDECT, GSM and CDMA.

Limitation of Wi-Fi networks:

The key areas of limitation of Wi-Fi are:

Coverage : A single Access Point can cover, at best, a radius of only about 60 metres.

Hundreds of Access Points are necessary to provide seamless coverage in small area. For 10

square kms area roughly 650 Access Points are required, where as CDMA 2000 1xEV-DO

requires just 09 sites.

Roaming : It lacks roaming between different networks hence wide spread coverage by one

service provider is not possible, which is the key to success of wireless technology.

Backhaul: Backhaul directly affects data rate service provider used Cable or DSL for

backhaul. Wi-Fi real world data rates are at least half of the their theoretical peak rates due to

factors such as signal strength, interference and radio overhead .Backhaul reduces the

remaining throughput further.

Interference: Wi-Fi uses unlicensed spectrum, which mean no regulator recourse against

interference. The most popular type of Wi- Fi, 802.11b uses the crowded 2.4 GHz band

which is already used in Bluetooth, cordless phones and microwave ovens.

Security: Wi-Fi Access Points and modems use the Wired Equivalent Privacy (WEP)

Standards, which is very susceptible to hacking and eavesdropping.

Security: WEP( Wired Equivalent Privacy) is not very secure. WPA (WIFI Protected

Access) offers much better security with the help of dynamic key encryption and mutual

authentication.

Authentication, Authorization and Accounting: In a server based configuration whenever

a laptop enters into a wifi zone, a welcome page is sent to it. User enters username and

password. It is connected through the wireless gateway(router) to AAA, LDAP servers. Once

authenticated ,user can access sites of his choice. Prepaid and postpaid customers can be

billed.


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WIMAXWi-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. Wi-MAX is based on a very flexible and robust air interface defined by the

IEEE 802.16 group. WiMAX defines a flexible all-IP-based network architecture that allows

for the exploitation of all the benefits of IP.WiMAX offers very high spectral efficiency.

WiMAX is similar to the wireless standard known as Wi-Fi, but on a much larger scale and at

faster speeds. WiMAX supports a number of advanced signal-processing techniques to

improve overall system capacity. These techniques include adaptive modulation and coding,

spatial multiplexing, and multiuser diversity. WiMAX has a very flexible MAC layer that can

accommodate a variety of traffic types, including voice, video, and multimedia, and provide

strong QoS. Robust security functions, such as strong encryption and mutual authentication,

are built into the WiMAX standard.

FEATURES OF WIMAX:

OFDM-based physical layer

Very high peak data rates

Scalable bandwidth and data rate support

Adaptive modulation and coding (AMC)

Link-layer retransmissions

Support for TDD and FDD OFDMA

Flexible and dynamic per user resource allocation

Support for advanced antenna techniques

Quality-of-service support

Robust security

Support for mobility

IP-based architecture

LEASED LINES

AND

MLLN- MANAGED LEASED LINE NETWORK

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


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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.

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.

DRAWBACK OF TRADITIONAL LEASED LINE CIRCUITS

1. Limited range of services - Only Plain Leased Line Service, Data cards support

only up to 64 kbps, no support for N x 64 Kbps.

2. From Operator pointt of view in case of Leased Line Circuit different boxes from

different vendors so difficult to manage & control.

3. No Centralized Monitoring or alarm or performance monitering.

Therefore we should have a control to all this, we are able to identify before the

customer know which circuit has gone faulty The solution to this is MLLN.

MLLN FEATURES:

1. MLLN is an integrated, fully managed , multi service digital network platform

through which service provider can offer a wide range of service at an optimal cost to

business subscriber.

2. Using NMS, MLLN can provide high speed Leased Line with improved QoS, high

availability & reliability.

3. Except for connecting the local lead to the MODEM all operations & maintenance iscarried out through ROT (Remote Operating Terminal)

242 ROT upto 2003 and 178 new ROT installed after 2003

4. NMS supports service provisioning, Network optimization, planning & service

monitering.

5. System offers end to end circuit creation and modification, circuit loop testing & fault

isolation, automatic rerouting of traffic in case of trunk failure, software

programmability of NTU etc.


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6. Banking, Financial institution, Stock market, paper industry, broadcasting & Internet

service Provider main customers for MLLN.

MLLN ADVANTAGES :

1. 24 hrs Performance Monitering of the circuit. (how much time circuit time up & down

and the reason for down time e.g MODEM switch off or other reason)

2. Circuit fault reports generated proactively.(Before customer know we should detect

the fault & rectify it)

3. On Demand the Bandwidth can be increased. (without changing the MODEM recreate

the circuit with the same MODEM)

4. Low lead time for new circuit provisioning. (Create & debug if any fault)

5. Protection against the failure of the circuit (through recovery Management process

either automatic or manually)

6. Long drive on single copper pair.( for 64 kbps 7 kms & for 2mbps 3.5 kms)

7. Centrally managed from ROT connected to the NMS

APPLICATION OF MLLN:

1. Corporate high speed internet access through Broadband.

2. LAN interconnection.

3. Hotline connectivity for voice.

4. Point to point connection for data circuit.

5. point to multipoint connection.

6. EPABX Interconnection.

7. VPN on MLLN Network.

8. Extension of VPN (MPLS) to Customer.

KEY ELEMENTS OF MLLN:

MLLN Nodes

Servers Workstations Networking Equipment Others (Printers, UPS etc)

MLLN NODES:

DXC (Digital Cross-Connect) VMUX (Versatile Multiplexer)

NTU (Network Terminating Unit)


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NMS (Network Management System)

NETWORK ARCHITECTURE:

NMS (Network Management System):

MLLN NMS performs all the management functions on the network. It Offered

Performance Monitoring, Recovery, Reporting Packages . It Supports regional partitioning

and VPN capabilities .

DXC(Digital Cross Connect):

Switch connects the temporary connection. In DXC bandwidth are interconnected to each

other and semipermanent. NMS is connected to DXC and all DXC are interconnected .

VMUX(Versatile multiplexer):

It is the device through which leased line is provided to the user.VMUX have different types

of ports are present of different bandwidth. It multiplex all the data in single line .

Main DXC256 Ports

DXC-64 DXC-64 DXC-128

VMUXs

Modems


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NTU(Network Terminating Unit):

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

modulate the signal at transmitter and demodulates it at receiver.

OPTICAL FIBER

Optical Fibre is new medium, in which information (voice, Data or Video) is transmitted

through a glass or plastic fibre, in the form of light, following the transmission sequence give

below :

(1) Information is Encoded into Electrical Signals.

(2) Electrical Signals are Coverted into light Signals.

(3) Light Travels Down the Fiber.

(4) A Detector Changes the Light Signals into Electrical Signals.

(5) Electrical Signals are Decoded into Information.

- Inexpensive light sources available.

- Repeater spacing increases along with operating speeds because low loss

fibres are used at high data rates.

Fig. 1


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Principle of Operation - Theory Total Internal Reflection - The Reflection that Occurs when a Ligh Ray Travelling

in One Material Hits a Different Material and Reflects Back into the Original

Material without any Loss of Light.

Fig. 2

Speed of light is actually the velocity of electromagnetic energy in vacuum such as space.

Light travels at slower velocities in other materials such as glass. Light travelling from one

material to another changes speed, which results in light changing its direction of travel. This

deflection of light is called Refraction.

The amount that a ray of light passing from a lower refractive index to a higher one is bent

towards the normal. But light going from a higher index to a lower one refracting away from

the normal, as shown in the figures.

Fig. 3

As the angle of incidence increases, the angle of refraction approaches 90 o to the normal.

The angle of incidence that yields an angle of refraction of 90 o is the critical angle. If the

angle of incidence increases amore than the critical angle, the light is totally reflected back

1

Angle of incidence

n 1n 2

2

n 1n 2

1

2

n 1n 2

1 2

Angle of reflection

Light is bent awayfrom normal

Light does not entersecond material


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into the first material so that it does not enter the second material. The angle of incidence and

reflection are equal and it is called Total Internal Reflection.

OPTICAL FIBRE PARAMETERS

Optical fiber systems have the following parameters.(I) Wavelength.

(II) Frequency.

(III) Window.

(IV) Attenuation.

(V) Dispersion.

(VI) Bandwidth.

(I) WAVELENGTH

It is a characterstic of light that is emitted from the light source and is measures innanometers (nm). In the visible spectrum, wavelength can be described as the colour of thelight.

For example, Red Light has longer wavelength than Blue Light, Typical wavelength for fibreuse are 850nm, 1300nm and 1550nm all of which are invisible.

(II) FREQUENCY

It is number of pulse per second emitted from a light source. Frequency is measured in unitsof hertz (Hz). In terms of optical pulse 1Hz = 1 pulse/ sec.

(III) WINDOW

A narrow window is defined as the range of wavelengths at which a fibre best operates.

(IV) ATTENUATION

Attenuation is defined as the loss of optical power over a set distance, a fibre with lowerattenuation will allow more power to reach a receiver than fibre with higher attenuation.Attenuation may be categorized as intrinsic or extrinsic.

INTRINSIC ATTENUATION

It is loss due to inherent or within the fibre. Intrinsic attenuation may occur as

(1) Absorption - Natural Impurities in the glass absorb light energy.

Absorption of Light

LightRay


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Scattering

EXTRINSIC ATTENUATIONIt is loss due to external sources. Extrinsic attenuation may occur as

(a) Macrobending - The fibre is sharply bent so that the light travelling down thefibre cannot make the turn & is lost in the cladding.

Micro and Macro bending

(b) Microbending - Microbending or small bends in the fibre caused bycrushing contraction etc. These bends may not be visible with the naked eye.

Attenuation is measured in decibels (dB). A dB represents the comparison between thetransmitted and received power in a system.

(V) DISPERSION

Dispersion is the spreading of light pulse as its travels down the length of an optical fibre asshown in figure 13. Dispersion limits the bandwidth or information carrying capacity of afibre. The bit-rates must be low enough to ensure that pulses are farther apart and thereforethe greater dispersion can be tolerated.

There are three main types of dispersion in a fibre -

(I) Modal Dispersion

(II) Material dispersion

(III) Waveguide dispersion

Light

Ray

Light is lost


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Fig. 13 Dispersion

(VI) BANDWIDTH

It is defined as the amount of information that a system can carry such that each pulse of lightis distinguishable by the receiver.

System bandwidth is measured in MHz or GHz. In general, when we say that a system has bandwidth of 20 MHz, means that 20 million pulses of light per second will travel down thefibre and each will be distinguishable by the receiver.

BANDWIDTH AND DISPERSION :

A bandwidth of 400 MHz -km means that a 400 MHz-signal can be transmitted for 1 km. Itmeans that the product of frequency and the length must be 400 or less. We can send a lowerfrequency for a longer distance, i.e. 200 MHz for 2 km or 100 MHz for 4 km. Multimodefibres are specified by the bandwidth-length product or simply bandwidth.

MPLS (Multi-Protocol Level Switching)The exponential growth of the Internet over the past several years has placed a tremendous

strain on the service provider networks. Not only has there been an increase in the number of

users but there has been a multifold increase in connection speeds.

MPLS technology enables Service Providers to offer additional services for their customers,scale their current offerings, and exercise more control over their growing networks by using

its traffic engineering capabilities.

MPLS Architecture :LSP

MPLS core LSR

Ingress

Egress

MP LS LER

LSP

MPLS core LSR

Ingress

Egress

MP LS LER
http://www.mplstutorial.com/mpls-tutorial-what-mpls-multi-protocol-label-switchttp://www.mplstutorial.com/mpls-tutorial-what-mpls-multi-protocol-label-switchttp://www.mplstutorial.com/mpls-tutorial-what-mpls-multi-protocol-label-switchttp://www.mplstutorial.com/mpls-tutorial-what-mpls-multi-protocol-label-switc


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MPLS operations :

I. Push:

A new label is pushed on top of the packet, effectively "encapsulating" the original IP packet

in a layer of MPLS.

II. Swap :

Every incoming label is replaced by a new outgoing label (As per the path to be followed)

and the packet is forwarded along the path associated with the new label.

III. Pop:

The label is removed from the packet effectively "de-encapsulating". If the popped label was

the last on the label stack, the packet "leaves" the MPLS tunnel.

Advantage:

I. Routing fast.

II. Addition of node is easy.

III. Conversion is fast.

Disadvantage:

I. Not secure.

II. Share the route.s

VPN(Virtual Private Network)

VPNs were originally introduced to enable service providers to use common physical

infrastructure to implement emulated point-to-point links between customer sites. A customer

network implemented with any VPN technology would contain distinct regions under the

customer's control called the customer sites connected to each other via the service provider

(SP) network. A full mesh of connected sites would consequently imply an exponential

increase in the cost associated.

Advantage:

I. Work from home.

II. Easy to implement in MPLS.


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training report on telecommunications bsnl

Documents