1

A

Mini Project Report on

“BROAD BAND ACCESS TECHNOLOGIES”

Submitted in partial fulfillment of the requirements for the award of the

Degree of

BACHELOR OF TECHNOLOGY

in

ELECTRONICS AND COMMUNICATION ENGINEERING

By

Satish Masina

(09P31A0486)

Under the supervision of

Mr. M. Kranthi Kumar (M Tech)

Assistant Professor,

ECE Dept.

DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING

SRI SAI ADITYA INSTITUTE OF SCIENCE AND TECHNOLOGY

(Affiliated to JNTUK, Kakinada & Approved by AICTE, New Delhi)

Surampalem, ADB Road, E. G. Dt., A.P - 533437.

2009– 2013

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CERTIFICATE

DEPARTMENT OF

ELECTRONICS AND COMMUNICATION ENGINEERING

This is to certify that Mr. MASINA SATISH participated in the Mini project under

the title of TELECOM TECHNOLOGIES, BSNL, KAKINADA, EAST GODAVARI Dist.,

ANDHRA PRADESH, during period from 07-05-2012 to 20-05-2012 and successfully

completed, the same as record of bonafied work carried out by the above student under my

guidance & supervision.

Internal Project Guide Head of the Department

M.Kranthi Kumar (M Tech) Mr.R.V.V.KRISHNA M Tech, (Ph.D)

Assistant Professor Associate Professor

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ACKNOWLEDGEMENT

Mini project has an important role in a shaping up an engineering student for practical

knowledge how a keeping him update with latest technology. First of all, I would like to express

my attitude towards Mr. V. Hanumantha Rao for his guidance throughout our mini project

work. With great pleasure we want to take this opportunity to express our heartfelt gratitude to

all the people who helped in making this mini project work a grand success.

We thank Mr. V. Ramesh Babu, D.E (Internal) of BSNL, Rajahmundry for extending their

utmost support and cooperation in providing all the provisions for the successful completion of

the project.

First of all we are highly indebted to Principal Dr. CH. Srinivasa Rao for giving us the

permission to carry out this mini project.

We would like to thank Mr. R. V. V. KRISHNA, Head of the Department of Electronics and

Communication Engineering, as our project guide for giving valuable suggestions.

Last but not the least, we express our sincere thanks to Asst. Prof. M. Kranthi Kumar for his

continuous care towards our achievements.

We would like to thank the Other Teaching Staff of ECE Department for sharing their

knowledge with us.

ABSTRACT

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It is not viable to expand the telecom network in India substantially at the prevalent level

of per-line investment. However, systems based on new technologies, many developed in India,

promise to more than halve the investment required.

This article looks at the telecom scenario, the new technologies, the Indian products

based on these technologies, and the cost reductions they promise. The provision of widespread

Internet service with low access tariff is an important aspect of the new approach.

In the era of Modernization and Globalization communication became the part and

parcel of human life, whereas BSNL is one of its kinds in such a communication.

The term broadband refers to a telecommunications signal or device of

greater bandwidth, in some sense, than another standard or usual signal or device (and the

broader the band, the greater the capacity for traffic).

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 with other services (such as voice telephone and home entertainment), price, and

availability.

Broadband communications technology can be divided broadly into wire line

technologies and wireless technologies.

Advantages of Broadband are Always on (Not on shared media), Fast (speed ranging

from 256 kbps), No disconnection, No additional access charge, Telephone and Data

simultaneously

INDEX

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TABLE OF CONTENTS Pg no

 1. BSNL OVERVIEW

A. External/Internal Infrastructure

B. BSNL Service

2. NATIONAL INTERNET BACKBONE (NIB)

A. Architectural principles

B. Infrastructure.

C. Economy

3. BROADBAND

A. Digital Subscriber Line (DSL)

B. Asymmetric Digital Subscriber Line (ADSL)

C. Very high Digital Subscriber Line (VDSL)

D. Digital Subscriber Line Access Multiplexer (DSLAM)

E. Routing.

F. Broadband Remote Access Server (BRAS)

G. Router

H. Service Control Module I. Wi-Fi

J. Wi-Max

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INTRODUCTION TO BSNL

Bharat Sanchar Nigam Ltd. formed in October, 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 service, MPLS-VPN,

VSAT, VoIP services, IN Services etc. Presently it is one of the largest & leading Public Sector

units in India.

BSNL has installed Quality Telecom Network in the country and now focusing on

improving it, expanding the Network, introducing new Telecom services with ICT applications

in villages and wining customer's confidence. Today, it has about 46 million line basic telephone

capacity, 5.06 Million WLL capacity, 52 Million GSM Capacity, more than 38302 fixed

exchanges, 46565 BTS, 3895 Node B ( 3G BTS), 287 Satellite Stations, 614755 RKM of OFC

Cable, 50430 RKM of Microwave Network connecting 602 Districts, 7330 cities/towns and 5.6

Lakhs villages.

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 its reach with its wide Network giving services in every nook & corner of

country and operates across India except Delhi & Mumbai. Whether it is in accessible areas of

Siachen glacier and North-eastern region of the country, BSNL serves its customers with its wide

bouquet of Telecom services.

BSNL is Numero-uno operator of India in all services in its license area. The company

offers vide ranging & most transparent tariff schemes designed to suite every customer.

BSNL Comprises of Cell One 90.09 Millions of 2G cellular customers and 88,493 3G

customers as on 30.11.2009. In basic services, BSNL is miles ahead of its rivals, with 35.1

million Basic Phone subscribers i.e. 85 per cent share of the subscriber base and 92 percent share

in revenue terms.

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BSNL has more than 2.5 million WLL subscribers and 2.5 million Internet Customers

who access Internet through various modes viz. Dial-up, Leased Line, DIAS, and Account less

Internet (CLI). BSNL has been adjudged as the NUMBER ONE ISP in the country.

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.

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BHARAT SANCHAR NIGAM LIMITED

(BSNL) OVERVIEW

Bharat Sanchar Nigam Limited (abbreviated BSNL) is  a  state owned telecommunications. Company

head quartered in New Delhi, India. BSNL is one of the

largest Indian cellular service providers, with over 87.1

million subscribers as of April2011, and the largest land

line telephone provider in India. However, in recent years

the company's revenue and market share plunged into

heavy losses due to intense competition in Indian

telecommunications sector

BSNL is India's oldest and largest communication service provider (CSP). It had a customer base of 90 million as

of June 2008. It has footprints throughout India except for the metropolitan cities of 

Mumbai and New Delhi, which are managed by Mahanagar  Telephone  Nigam Limited (MTNL). As of

June 30, 2010, BSNL had a customer base of 27.45 million wire line and 72.69million wireless subscriber

It is India’s largest telecommunication company with 24% market share as on March

31st2008.Its headquarters are at Bharat Sanchar Bhawan, Harish Chandra Mathur Lane, New Delhi. It has

the status of MINI RATNA, a status assigned to public sector companies in India.

External/internal infrastructure: External infrastructure: Lines and cables (U/G include)

Internal infrastructure: Battery, Power Plant E/A, A/C plant, MDF, Switches (C-DOT, OCB 283, EWSD, AXE etc), Leased Lines (MLLN), Broad Band, MPLS VPN.

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Interesting Facts:

  There are 2 million BSNL mobile connections in rural

India (a record, no other connection is as famous as BSNL in rural areas)

BSNL supplies phone lines to all other network such as Airtel, Vodafone etc.

Largest pan India coverage-over 11000 towns & 3 lakh Villages.

India’s No. 1 wireless service provider with more than 50 Million customers.

An incredible speed of 2mbps is only offered by BSNL

BSNL Services:

1. BSNL LANDLINE

NEW TELEPHONE CONNECTION

PERMANENT CONNECTION

CONCESSION IN RENTALS

SHIFT OF TELEPHONE

TRANSFER OF TELEPHONE

TELEPHONE TARIFF

2) BSNL MOBILE

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POSTPAID

PREPAID

UNIFIED MESSAGING

GPRS/WAP/MMS

DEMOs

TARIFF

SMS & BULK SMS

3) BSNL WLL

4) INTERNET SERVICES

NETWORK

BROADBAND

TYPES OF ACCESS

INTERBET TARIFF

DIAL-UP INTRENET

Wi-Fi

5) BSNL BROADBAND

REGISTER ONLINE

TARIFF

CHECK USAGE

FAQ

6) ISDN

ISDN

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TARIFF 7) VIDEO CONFERRENCING

OVERVIEW

TARIFF

FAQ

8) AUDIO CONFERRENCING

OVERVIEW

TARIFF

FAQ

9) TELEX/TELEGRAPH

TELEX/TELEGRAGH

TARIFF

10) INET

OVERVIEW

SERVICES ON I NET

USING ON I NET

11) EPABX

EPABX

CENTREX

TRANSPONDER

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National Internet Backbone (NIB):

The Internet backbone refers to the principal data routes between large, strategically interconnected

networks and core routers in the Internet. 

These  data routes are hosted by commercial,

government, academic and other high

capacity network centers, the Internet

exchange points and network that interchange

Internet traffic between the countries, continents

and across the oceans of the world.

Architectural Principles:

The Internet, and consequently its

backbone networks, does not rely on central control or coordinating facilities, nor do they implement any global

network policies. The resilience of the Internet results from its principal architectural features, most notably the idea

of placing as few network state and control functions as possible in the network elements, but instead relying on

the endpoints of communication to handle most of the processing to ensure data integrity, reliability ,and

authentication. In addition, the high degree of redundancy of today's network links andsophisticated real-

time routing protocols provide alternate paths of communications for load balancing and congestion avoidance.

Infrastructure:

The internet backbone is a conglomeration of multiple, redundant networks owned by numerous

companies. It is typically a fiber optic trunk line. The trunk line consists of many fiber optic cables bundled

together to increase the capacity. The backbone is able to re route traffic in case of a failure. The data speeds of

backbone lines have changed with the times. In 1998, all of the United States backbone networks had utilized the

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slowest data rate of 45 Mbps. However the changing technologies allowed for 41 percent of backbones to have

data rates of 2,488 Mbps or faster by the mid 2000's. The FCC currently defines "high speed" as any connection

with data speeds that exceed 200 kilobits per second. An Azerbaijani based telecommunication company, Delta

Telecom, has recently developed a very efficient trunk line with possible speeds of to 1.6terabits per second.

Internet traffic from this line goes through the countries of Iran, Iraq and Georgia. Fiber-optic cables are the

medium of choice for internet backbone providers for many reasons. Fiber-optics allows for fast data speeds and

large bandwidth; they suffer relatively little attenuation, allowing them to cover long distances with few repeaters;

they are also immune to crosstalk and other forms of EM interference which plague electrical transmission.

Modern Backbone:

Because of the enormous overlap between long distance telephone networks and the internet backbone

networks, the largest long distance voice carriers such as AT&T, MCI, Sprint and west also own some of the

largest internet backbone networks. These backbone providers will then sell their service to ISPs. Each ISP has

its own contingency backbone network, and at the very least, is equipped with an outsourced backup. These

networks are intertwined and criss-crossed to create a redundant network. Many companies operate their own

backbones that are all interconnected at various NAPs around the world. In order for data to navigate through this

diverse web that the backbone creates, backbone routers are desperately needed. These backbone routers are

routers that are powerful enough to handle information on the internet backbone, and they direct data to other

routers in order to send it to its final destination. Without these backbone routers, information would be lost since

data would not know how to locate its end destination. The very largest providers, known as Tier

1 providers, have such comprehensive networks that they never need to purchase transit agreements from other

providers. As of 2000 there were only five internet backbone providers at the Tier 1 level in the

telecommunications industry.

NIB in India:

India's backbone is very extensive due to a very large population. This country alone has nearly 250 million

internet users as of 2009. Four of India's top Internet Service Providers are Tata Communications, BSNL, MTNL,

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and Reliance Communications. Tata Communications is a Tier-1 IP network, with connectivity to more than 200

countries across 400 Pops and nearly 1,000,000square feet (93,000 m2) of data center and collocation space

worldwide. It is India's largest provider in data center services and also operates India's largest data center in Pune.

The backbone structure keeps on getting stronger because of the huge number of new emerging mobile operators

which leads to decrease in prices due to competition in the market.

Economy of the Backbone:

Peering agreements: Backbone providers of roughly equivalent market share regularly create

agreements called peering  agreements. These  agreements  allow  the use of another's network to hand off

traffic where is ultimately delivered. They usually do not charge each other for this use as they all get revenue from

their customers regardless.

Transit agreements: Backbone providers of unequal market share usually create agreements called transit

agreements, and usually contain some type of monetary agreement.

Regulation: Antitrust authorities have acted to ensure that no provider grows large enough to dominate the

backbone market. The FCC has also decided not to monitor the competitive aspects of the Internet Backbone

interconnection relationships, as long as the market continues to function well without regulation

Broadband:

The term broad band refers to a telecommunications signal of greater bandwidth, in some

sense, than another standard or usual signal (and the broader the band, the greater the capacity for traffic). Different

criteria for "broad" have been applied in different contexts and at different times. Broadband in

telecommunications refers to a signaling method that includes or handles a relatively wide range (or band) of

frequencies, which may be divided into channels or frequency bins. Broadband is always a relative

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term, understood according to its context. The wider (or broader) the bandwidth of a channel, the greater the

information-carrying capacity. In radio, for example, a very narrow-band signal will carry Morse code; a broader

band will carry speech; a still broader band is required to carry music without losing the high audio frequencies

required for realistic sound reproduction. A television antenna described as "broadband" may be capable

of receiving a wide range of channels; while a single-frequency or Lo-VHF antenna is "narrow band" since it only

receives 1 to 5 channels. In data communications a digital modem will transmit a data rate of 56 kilobits per

seconds (k bit/s) over a 4 kilohertz wide telephone line (narrowband or voice band). However when that same line

is converted to an non-loaded twisted-pair wire (no telephone filters), it becomes hundreds of kilohertz wide

(broadband) and can carry several megabits per second (ADSL)

Technology:

The standard broadband technologies in most areas are ADSL and cable internet. Newer

technologies in use include VDSL and pushing optical fiber connections closer to the subscriber in both telephone

and cable plants. Fiber-optic communication, while only recently being

usedin fiber to the premises and fiber to the curb schemes, has played a crucial role in enabling Broadband

Internet access by making transmission of information over larger distances much more cost-effective than copper

wire technology.

In a few areas not served by cable or ADSL, community organizations have begun to install

Wi-Fi networks, and in some cities and towns local governments are installing municipal Wi-Fi networks. The

newest technology being deployed for mobile and stationary broadband access is Wi MAX.

Broadband in DSL:

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The various forms of digital subscriber line (DSL) services are broadband in the sense that digital

information is sent over a high-bandwidth channel. This channel is located above (i.e., at higher frequency than)

the baseband voice channel on a single pair of wires.

Digital Subscriber Line:

Digital Subscriber Line (DSL) is a family of technologies that provides digital data transmission over

the wires of a local telephone network. DSL originally stood for digital subscriber loop. In

telecommunications marketing, the term Digital Subscriber Line is widely understood to mean Asymmetric

Digital Subscriber Line (ADSL), the most commonly installed technical variety of DSL. DSL service is

delivered simultaneously with regular telephone on the same telephone line. This is possible because DSL

uses a higher frequency. These frequency bands are subsequently separated by filtering.

The data throughput of consumer DSL services typically ranges from 256 Kb/s to 40Mbit/s in

the direction to the customer (downstream), depending on DSL technology, line conditions, and service-level

implementation. In ADSL, the data throughput in the upstream direction, (i.e. in the direction to the service

provider) is lower, hence the designation of asymmetric

service. In Symmetric Digital Subscriber Line (SDSL) service, the downstream and upstream data rates are

equal.

Basic technology:

Telephones are connected to the telephone exchange via a local loop, which is a physical

pair of wires. Prior to the digital age, the use of the local loop for anything other than the transmission of

speech, encompassing an audio frequency range of 300 to 3400 Hertz(voice band or commercial

bandwidth) was not considered. However, as long distance trunks were gradually converted from analog to

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digital operation, the idea of being able to pass data through the local loop took hold, ultimately leading In

current practice, speech is digitized by using an analog-to-digital converter sampling at a rate of 8000

samples per second, capturing eight-bit values and producing a 64 kilobit per second data stream.

According to the Nyquist Shannon sampling theorem, if an input audio signal injected into such an analog-

to-digital converter contains frequency components higher than half of the sampling frequency, then such

high frequency components will be aliased by the system, and so must be blocked at the input by an

appropriate low-pass filter in order to prevent such effects. Due to the presence of the low-pass filter, input

frequencies above four kilohertz (KHz)will be blocked, preventing the passage of arbitrarily high frequencies

through the normal telephone voice path

The local loop connecting the telephone exchange to most subscribers has the capability

of carrying frequencies well beyond the 3.4 kHz upper limit of POTS. Depending on the length and quality

of the loop, the upper limit can be tens of megahertz. DSL takes advantage of this unused bandwidth of the

local loop by creating 4312.5 Hz wide channels starting between 10 and100 kHz, depending on how the

system is configured. Allocation of channels continues at higher and higher frequencies (up to 1.1 MHz for

ADSL) until new channels are deemed unusable. Each channel is evaluated for usability in much the same

way an analog modem would on a POTS connection. More usable channels equates to more available

bandwidth, which is why distance and line quality are a factor (the higher frequencies used by DSL travel

only short distances). The pool of usable channels is then split into two different

frequency bands

forupstream and downstream traffic, based on a preconfigured ratio. This segregation reduces interference.

Once the channel groups have been established, the individual channels are bonded into a pair of virtual

circuits, one in each direction. Like analog modems, DSL transceivers constantly monitor the quality of each

channel and will add or remove them from service depending on whether they are usable.

Network Connectivity Diagram:

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Typical setup and connection procedures

Physical connection must come first. On the customer side, the DSL Transceiver, or

ATU-R, or more commonly known as a DSL modem, is hooked up to a phone line. The telephone

company (telco) connects the other end of the line to a DSLAM, which concentrates a large number

of individual DSL connections into a single box. The location of the DSLAM depends on the telco,

but it cannot be located too far from the user because of attenuation, the loss of data due to the large

amount of electrical resistance encountered as the data moves between the DSLAM and the user's

DSL modem. It is common for a few residential blocks to be connected to one DSLAM.

When the DSL modem powers up it goes through a sync procedure. The actual process varies from modem

to modem but generally involves the following steps:

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1. The DSL transceiver performs a self-test.

2. The DSL transceiver checks the connection between the DSL transceiver and the computer. For

residential variations of DSL, this is usually the Ethernet (RJ-45) port or a USB port; in

rare models, a FireWire port is used. Older DSL modems sported a native ATM interface (usually, a 25 M

bit serial interface). Also, some variations of DSL (such as SDSL) use synchronous serial connections.

3. The DSL transceiver then attempts to synchronize with the DSLAM. Data can only come into the

computer when the DSLAM and the modem are synchronized. The synchronization process is relatively

quick (in the range of seconds) but is very complex, involving extensive tests that allow both sides of the

connection to optimize the performance according to the characteristics of the line in use. External or stand-

alone modem units have an indicator labeled "CD", "DSL", or "LINK", which can be used to tellif the

modem is synchronized. During synchronization the light flashes; when synchronized, the light stays lit,

usually with a green color.

The accompanying figure is a schematic of a simple DSL connection (in blue). The right side the shows a

DSLAM residing in the telephone company's central office. The left side shows the customer premises

equipment with an optional router. This router manages a local area network (LAN) off of which are

connected some number of PCs. With many service providers, the customer may opt for a modem which

contains a wireless router. This option (within the dashed bubble) often simplifies the connection

DSL Connection schematic

Equipment:

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The customer end of the connection consists of a terminal adaptor or in layman's terms" DSL modem". This

converts data between the digital signals used by computers and the voltage signal of a suitable frequency

range which is then applied to the phone line.

In some DSL variations (for example, HDSL), the terminal adapter connects directly to

thecomputer via a serial interface, using protocols such as ethernet or V.35. In other cases(particularly

ADSL), it is common for the customer equipment to be integrated with higher level functionality, such as

routing, firewalling, or other application-specific hardware and software. In this case, the equipment is

referred to as a gateway.

Some kinds of DSL technology require installation of appropriate filters to separate, or "split",

the DSL signal from the low frequency voice signal. The separation can take place either at the demarcation

point, or with filters installed at the telephone outlets inside the customer premises. Either way has its

practical and economical limitations. See ADSL for more information about this.

At the exchange, a digital subscriber line access multiplexer (DSLAM) terminates the DSL

circuits and aggregates them, where they are handed off onto other networking transports. In the case of

ADSL, the voice component is also separated at this step, either by a filter integrated in the DSLAM or by

specialized filtering equipment installed before it. The DSLAM terminates all connections and recovers the

original digital information.

Brief Functions of DSL Components:

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DSL CPEs: At customer premises. On end it connects telephone cable coming from exchange. At the

other end, it connects to PC through Ethernet and Telephone through RJ-45 connector

DSLAM: called as DSL Access Multiplexer. It has a built in splitter which splits voice and data. While

voice follows the normal conventional path through exchange, data is aggregated and up linked through

Ethernet Port (Gigabit Ethernet for 480 port and Fast Ethernet for lower DSLAM)

LAN Switch: For aggregating multiple DSLAM and providing a common uplink

BRAS: called as Broadband Remote Access Server. First intelligent device in the whole chain. It terminates

the customer session, authenticates, a lot IP addresses and keeps track of user session for billing along with

RADIUS

SSSS: Called as Subscriber Service Selection System. When customer logs in he will be welcome with this

customized screen from where he can select various range of service. This provides on demand service

without manual intervention

RADIUS: This in conjunction with BRAS authenticates customer, upload customer profile in the SSSS and

keeps track of billing

LDAP: It stores customer database viz username, password and the default services that itcan subscribe to.

Provisioning: This is the most critical components for ensuring quick delivery of service.It ensures end-to-

end provisioning of service right from DSL CPEs to DSLAM to Switchto BRAS to LDAP

Asymmetric Digital Subscriber line (ADSL): The distinguishing characteristic of ADSL over other

forms of DSL is that the bandwidth is greater in the direction to the customer premises than the reverse,

giving rise to is asymmetric characteristic. Providers usually market ADSL as a service for consumers to

connect to the Internet in a relatively passive mode: able to use the higher speed direction for the download

from the Internet but not needing to run servers that would require high speed in the other direction With

standard ADSL the band from 26.000 kHz to 137.825 kHz is used for upstream communication, while 138

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kHz-1104 kHz is used for downstream communication. Each of these is further divided into smaller

frequency channels of 4.3125 kHz. These frequency channels are sometimes termed bins.

Very high bit rate digital subscriber line (VDSL):It is a DSL technology providing faster data

transmission (up to 52 Mbps downstream and16 Mbps upstream) Second-generation VDSL2 systems (ITU-

T G.993.2 Approved in February2006) utilize bandwidth of up to 30 MHz to provide data rates exceeding

100 M bits simultaneously in both the upstream and downstream directions. The maximum available bit rate

is achieved at a range of about 300 meters; performance degrades as the loop attenuation increases. Currently,

the standard VDSL uses up to 7 different frequency bands

Digital Subscriber Line Access Multiplexer:

A Digital Subscriber Line Access Multiplexer(DSLAM, often pronounced dee-slam)allows

telephone lines to make faster connections to the Internet. It is a network device, located in the telephone

exchanges of the internet service providers, that connects multiple customer Digital Subscriber Lines (DSLs)

to a high-speed Internet backbone line using multiplexing techniques. By placing additional remote

DSLAMs at locations remote to the telephone exchange, telephone companies provide DSL service to

locations previously beyond effective range.

Path taken by data to DSLAM:

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1.Customer premises: DSL modem terminating the ADSL, SHDSL or VDSL circuit andproviding

LAN interface to single computer or LAN segment

2. Local loop: The telephone company wires from a customer to the telephone company' scentral office

or to a Serving area interface, often called the "last mile" (LM).

3. Central Office(CO):

Main Distribution Frame (MDF): a wiring rack that connects outside subscriber

lines with internal lines. It is used to connect public or private lines coming into the building to internal

networks. At the telco, the MDF is generally in proximity to the cable vault and not far from the telephone

switch. XDSL filters: DSL filters are used in the Central Office (CO) to split voice from data signals. The

voice signal can be routed to a POTS provider or left unused whilst the data signal is routed to the ISP

DSLAM via the HDF (see next entry).Handover Distribution Frame (HDF): a distribution frame that

connects the last mile provider with the service provider's DSLAM

DSLAM: A device for DSL service. The DSLAM port where the subscriber local loop is connected

converts analog electrical signals to data traffic (upstream traffic for data upload) and data traffic to analog

electrical signals (downstream for data download).

XDSL Connectivity diagram

Role of DSLAM:

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The DSLAM equipment at the telephone company (telco) collects the data

from its many modem ports and aggregates their voice and data traffic into one complex composite "signal"

via multiplexing.

The aggregated traffic is then directed to a telco's backbone switch, via an access

network (AN) also called a Network Service Provider (NSP) at up to 10 G bit/s data rates.

The DSLAM acts like a network switch since its functionality is at Layer 2 of the OSI

model. Therefore it cannot re-route traffic between multiple IP networks, only

between ISP devices and end-user connection points. 

The DSLAM  traffic is switched to a Broadband Remote Access Server where

the end user traffic is then routed across the ISP network to the Internet. Customer Premises Equipment that

interfaces well with the DSLAM to which it is connected may take advantage of enhanced telephone voice

and data line signaling features and the bandwidth monitoring and compensation capabilities it supports.

DSLAMs are also used by hotels, lodges, residential neighborhoods, and other

businesses operating their own private telephone exchange .In addition to being a data switch and

multiplexer, a DSLAM is also a large collection of modems. Each modem on the aggregation

card communicates with a single subscriber's DSL modem. This modem functionality is integrated into the

DSLAM itself instead of being done via an external device like a traditional computer modem. Like

traditional voice-band modems, a DSLAM's integrated DSL modems usually have the ability to probe the

line and to adjust themselves to electronically or digitally compensate for forward echoes and other

bandwidth-limiting factors in order to move data at the maximum connection rate capability of the

subscriber's physical line. This compensation capability also takes advantage of the better performance of

"balanced line" DSL connections, providing capabilities for LAN segments longer than physically similar

unshielded twisted pair (UTP) Ethernet connections, since the balanced line type is generally required for its

hardware to function correctly. This is due to the nominal line impedance (measured in Ohms but comprising

both resistance and inductance) of balanced lines being somewhat lower than that of UTP, thus supporting

'weaker' signals (however the solid-state electronics required to construct such digital interfaces is more

costly).

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Tier 2 Network A Tier 2 Network is an Internet service provider who engages in the practice of

peering with other networks, but who still purchases IP transit to reach some portion of the Internet.

Tier 2 providers are the most common providers on the Internet as it is much easier to

purchase transit from a Tier 1 network than it is to peer with them and then attempt to push into becoming a

Tier 1 carrier

Tier 1 Network:

Although there is no authority that defines tiers of networks participating in the Internet, the most

common definition of a tier 1 network is one that can reach every other network on the Internet without

purchasing IP transit or paying settlements.

 

By this definition, a tier 1 network is a transit-free network that peers with every other tier-1

network. But not all transit-free networks are tier 1 networks. It is possible to become transit-free by paying

for peering or agreeing to settlements. It is difficult to determine whether a network is paying settlements if

the business agreements are not public information, or covered under a non-disclosure agreement. The

Internet "peering community" is roughly the set of peering coordinators present at Internet exchanges on

more than one continent. 

The subset representing "tier 1"networks is collectively understood, but not published as

such. Strictly observing this definition of "tier 1" would exclude every network. For instance, many large

telephone companies are tier 1 networks, but they buy, sell, or swap fiber amongst themselves. Payments

between companies are not all known, nor whether they cover peering connections.

As a result, the term "tier 1 network" is used in the industry to mean a network with no overt settlements. An

overt settlement would be a monetary charge for the amount, direction, or type of traffic sent between

networks.

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Routing:

Internet traffic between any two tier 1 networks is critically dependent on the peering relationship of the

partners, because a tier 1 network does not have any alternate transit paths. If two tier 1 networks arrive at an

impasse and discontinue peering with each other (usually in auni lateral decision), single-homed customers

of each network will not be able to reach the customers of other networks. This effectively partitions the

Internet and traffic between certain parts of the Internet is interrupted. This has happened several times during

the history of the Internet. Those portions of the Internet typically remain partitioned until one side purchases

transit, or until the collective pain of the outage or threat of litigation motivates the two networks to resume

voluntary peering.

 

Lower tier ISPs and their customers may be unaffected by these

partitions because they may have redundant interconnections with more than one

tier-1 provider. Frequent misconceptions of the tier hierarchy include:

Tier 1 networks are closer to the backbone of the Internet.

In reality, tier 1 networks usually have only a small number of peers

(typically only other tier 1 networks and very large tier 2 networks), while

tier 2 networks are motivated to peer with many other tier 2 and end-user

networks. Thus a tier 2 network with good peering is frequently much closer

to most end users than a tier 1.

Tier 1 networks by definition offer better quality Internet connectivity.

By definition, there are networks which tier 1 networks have only one path

to, and if they lose that path, they have no backup transit which preserves

their continuous connectivity.

Some tier 2 networks are significantly larger than some tier 1 networks, and

are often a let provide more or better connectivity

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Broadband Remote Access Server (BRAS):

A broadband remote access server(BRASB-RAS or BBRAS) routes traffic to

andfrom broadband remote access devices such as digital subscriber line accessmultiplexers (DSLAM) on

an Internet service provider's (ISP) network.

The BRAS sits at the core of an ISP's network, and aggregates user sessions from the

access network. It is at the BRAS that an ISP can inject policy management and IP Quality of Service (QoS).

The specific tasks include:

Aggregates the circuits from one or more link access devices such as DSLAMs

Provides layer 2 connectivity through either transparent bridging or PPP sessionsover Ethernet or

ATM sessions

Enforces quality of service (QoS) policies

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Provides layer 3 connectivity and routes IP traffic through an Internet service provider’s Back

bone network to the Internet

A DSLAM collects data traffic from multiple subscribers into a centralized point so that it can be

transported to a switch or router over a Frame Relay, ATM, or Ethernet connection. The router

provides the logical network termination. The BRAS is also the interface to authentication,

authorization and accounting systems

Internet Router: A router is a device that forwards data packets across computer networks. Routers perform

the data "traffic directing" functions on the Internet. A router is connected to two or more data lines from

different networks. When data comes in on one of the lines, the router reads the address information in the

packet to determine its ultimate destination. Then, using information in its routing table, it directs the packet

to the next network on its journey or drops the packet. A data packet is typically passed from router to router

through the networks of the Internet until it gets to its destination computer unless the source IP is on a private

network.

 

The most familiar type of routers are home and small office routers that simply pass data,

such as web pages and email, between the home computers and the owner's cable or DSL modem, which

connects to the Internet (ISP).In enterprises, a core router may provide a "collapsed backbone"

interconnecting the distribution tier routers from multiple buildings of a campus, or large enterprise locations.

They tend to be optimized for high bandwidth

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A typical home or small office router showing the ADSL telephone line and ETHERNET network cable connections.Forwarding: The main purpose of a router is to connect multiple networks and forward packets

destined either for its own networks or other networks. A router is considered a Layer 3 device because its

primary forwarding decision is based on the information in the Layer 3 IP packet, specifically the destination

IP address. This process is known as routing. When each router receives a packet, it searches its routing table

to find the best match between the destination IP address of the packet and one of the network addresses in

the routing table. Once a match is found, the packet is encapsulated in the Layer 2 data link frame for that

outgoing interface. A router does not look into the actual data contents that the packet carries, but only at the

layer 3 addresses to make a forwarding decision, plus optionally other information in the header for hint on,

for example, QoS. Once a packet is forwarded, the router does not retain any historical information about the

packet, but the forwarding action can be collected into the statistical data, if so configured.

  Forwarding decisions can involve decisions at layers other than layer 3. A function that

forwards based on layer 2 information, is properly called a bridge. This function is referred to as layer 2

bridging, as the addresses it uses to forward the traffic are layer 2 addresses (e.g. MAC addresses on

Ethernet).

Besides making decision as which interface a packet is forwarded to, which is

handled primarily via the routing table, a router also has to manage congestion, when packets arrive at ar ate

higher than the router can process. Three policies commonly used in the Internet are tail drop, random early

detection (RED), and weighted random early detection (WRED). Tail drop is the simplest and most easily

implemented; the router simply drops packets once the length of the queue exceeds the size of the buffers in

the router. RED probabilistically drops data grams early when the queue exceeds a pre-configured portion of

the buffer, until a pre-determined max, when it becomes tail drop. WRED requires a weight on the average

queue size to act upon when the traffic is about to exceed the pre-configured size, so that short bursts will not

trigger random drops.

Another function a router performs is to decide which packet should be

processed first when multiple queues exist. This is managed through quality of service (QoS), which is

critical when Voice over IP is deployed, so that delays between packets do not exceed 150ms to maintain the

quality of voice conversations. Yet another function a router performs is called policy-based routing where

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special rules are constructed to override the rules derived from the routing table when a packet forwarding

decision is made. These functions may be performed through the same internal paths that the packets travel

inside the router. Some of the functions may be performed through an application-specific integrated circuit

(ASIC) to avoid overhead caused by multiple CPU cycles, and others may have to be performed through the

CPU as these packets need special attention that cannot be handled by an ASIC.

Service control module:

It is responsible for authentication and management of user access requests. It identifies legal

users. It can extract and record the statistics of user data packets and online duration for implementing the

traffic based or duration based accounting function.

MA5200G sends the user’s accounting information to the RADIUS server. BRAS

allocates IP address through DHCP. It supports 4k to 96k IP addresses.MA5200G adopts packet binding

technology. After user passes authentication It checks the binding relation of the IP address, MAC address,

logical port and PPPoE session ID in each packet of this user and the packets that do not match will be

discarded.

Wi-Fi:

Wireless Technology is an alternative to wired Technology for connecting the devices in wireless mode. Wi-

Fi refers to the IEEE 802.11 communication standard for wireless LAN. Wi-Fi network connect computers

to each other to the internet and to the other wired networks. Wi-Fi networks use Radio Technologies to

transmit & receive date at high speeds.

Wi MAX:

Wi MAX (Worldwide Interoperability for Microwave Access) is a telecommunications

protocol that provides fixed and mobile Internet access. The current Wi MAX revision provides up to 40 M

bit/s with the IEEE 802.16m update expected to offer up to 1 G bit/s fixed speeds. The name "Wi-MAX"

was created by the Wi MAX Forum, which was formed in June 2001to promote conformity and

interoperability of the standard. The forum describes Wi MAX as "a standards-based technology enabling the

delivery of last mile wireless broadband access as an alternative to cable.

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Comparison between Wi-Fi and Wi-MAX:

Comparisons and confusion between Wi MAX and Wi-Fi are frequent because both are related to

wireless connectivity and Internet access.

Wi MAX is a long range system, covering many kilometers that uses licensed or unlicensed

spectrum to deliver connection to a network, in most cases the Internet whereas Wi-Fi uses

unlicensed spectrum to provide access to a local network.

Wi-Fi runs on the Media Access Control's CSMA/CA protocol, which is connectionless and

contention based, whereas Wi MAX runs a connection-oriented MAC.

Wi MAX and Wi-Fi have quite different quality of service (QoS) mechanisms. WiMAX uses a QoS

mechanism based on connections between the base station and the user device. Each connection is

based on specific scheduling algorithms

Advantages of Broadband:

Connection speed is up to 100 times faster than dialup connection. You can download pictures

files, software in seconds or minutes instead of hours. Online gaming is only possible using

a broadband internet access. It does not affect the phone line. For DSL internet access, you can use

the same phone line for both voice/fax and data transmission. For cable internet access, you are

connected to the internet via the cable network. In either case, your phone line is not occupied while

you are connected to the internet

It is convenient because the internet connection is always on.

You don't need to dial an access number and risk getting a busy signal.

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Broadband internet offers unlimited access and you won't be charged based on the connection

duration.

Broadband internet not only gives you high speed internet access, it can also provide cheap phone

services via VoIP technology.

Disadvantages of Broadband:

High monthly fee compared to dialup internet access.

Higher security risk than dialup connection. A personal firewall is needed to protect your computer.

Not all phone wires are equipped for DSL service.

Not all cable TV networks are equipped for cable internet access.

May not be available in rural or remote areas.

Applications:

In telecommunication:

Broadband in telecommunications refers to a signaling method that includes or handles a

relatively wide range (or band) of frequencies, which may be divided into channels or frequency bins. The

wider the bandwidth of a channel, the greater the information-carrying capacity.

Telemedicine

enables health care professionals and patients to take advantage of digital communications to

save money, time, and travel and most importantly, improve the quality of care.

Teleworking or telecommuting is working from home or outside the traditional office or workplace

using a digital device and an Internet connection. Telework benefits employers

who see savings in

 

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Information Gathering:

More and more people are using the Internet to gather information for anything from medical

information to job searching and news and information and shopping.

Tourism:

Broadband and community content allow people to find out what is available in tourist

destinations and also helps people to see events or exhibits they might otherwise never be able to visit in

person.

Entertainment:

Many people use the Internet for fun, to play games, gamble, download movies, music, TV

shows, books or information and services. As technology advances the applications and opportunities for e-

commerce and entertainment expand exponentially Office overhead costs as well as increased productivity

and motivation of their employees.

E-Government: refers to the increasing push for government at all levels to make more services available

online. Local governments use e-Government to deliver services and information to their residents and

customers 24 hours a day, seven days a week.

Public Safety: Broadband networks can assist police, fire and other law enforcement personnel in many

crisis situations.

National Security:

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Broadband can be used by national, state and local authorities for surveillance,

videoconferencing, data mining, pattern matching and other applications to assist law enforcement and

medical services.

CONCLUSION

I have learned about the broadband internet connectivity using the dsl connections, wifi

connectivity and internet through land phones, Problems persisting while connecting the

internet, new technologies about wi-max and remote access servicing at bsnl

sanchar bhavan.

Reference:

By Using internet and TSSN textbook.