Broadband network overview bsnl industrial training engineering

Slide No. 1 of 45
BROADBAND NETWORK
OVERVIEW
© BHARAT SANCHAR NIGAM LIMITED

Slide No. 2 of 45
AGENDA
- Broadband and its advantages
- Wired Broadband Access Technologies
- xDSLTechnology
- ADSL Technology in Details
- Do’s and Don’ts, Speed Check, Data Usage etc.
- Line Parameters for Broadband

Slide No. 3 of 45
One of the latest trends in enhancing communication
systems involves Broadband technology
Broadband refers to greater bandwidth-or
transmission capacity of a medium
Broadband technology will allow for high-speed
transmission of voice, video, and data over networks
like the Internet
Introduction of Broad-Band

Slide No. 4 of 45
BROADBAND
Telephone
TV
VoD
Broadband “Pipe”
Internet
Videoconference
???

Slide No. 6 of 45
TRAI DEFINITION OF BROADBAND
An ‘always-on’ data connection supporting interactive services
including Internet access and has the capability of the
minimum download speed of 512 kilo bits per second (kbps)
to an individual subscriber from the Point Of Presence (POP)
of the service provider.

ADVANTAGES OF BROADBAND
• Always on (Not a Shared Media) , fast internet
connections
• Fast downloads even for files with complex graphics
and pictures.
• Get streaming contents like streaming video, Games
on demand without interruption.
• Simultaneous use of telephone and internet.
• Saves time and money.
• Simple monthly charges.
• No telephone call charges for internet access.

Slide No. 8 of 45
WIRED BROADBAND TECHNOLOGIES
Digital Subscriber Lines (DSL)
Cable Modem (CM)
Fiber Technology (FTTH/B/C)
Power line Broadband(BPL)

DIAL-UP ACCESS
Dial-up Internet access uses a modem and a phone call placed over the
public switched telephone network (PSTN) to connect to a pool of
modems operated by an ISP.
Dial-up is often the only form of Internet access available in rural areas
as it requires no new infrastructure beyond the already existing
telephone network, to connect to the Internet. Typically, dial-up
connections do not exceed a speed of 56 kbit/s, as they are primarily
made using modems that operate at a maximum data rate of 56 kbit/s
downstream (towards the end user) and 34 or 48 kbit/s upstream
(toward the global Internet).

INTEGRATED SERVICES DIGITAL NETWORK
Integrated Services Digital Network (ISDN) is a switched telephone
service capable of transporting voice and digital data, is one of the
oldest Internet access methods. ISDN has been used for voice, video
conferencing, and broadband data applications. ISDN was very popular
in Europe, but less common in North America. Its use peaked in the late
1990s before the availability of DSL and cable modem technologies.
Basic rate ISDN, known as ISDN-BRI, has two 64 kbit/s "bearer" or "B"
channels. These channels can be used separately for voice or data calls
or bonded together to provide a 128 kbit/s service. Multiple ISDNBRI
lines can be bonded together to provide data rates above 128 kbit/s.
Primary rate ISDN, known as ISDN-PRI, has 23 bearer channels (64 kbit/s
each) for a combined data rate of 1.5 Mbit/s (US standard). An ISDN E1
(European standard) line has 30 bearer channels and a combined data
rate of 1.9 Mbit/s.

LEASED LINES
Leased lines are dedicated lines used primarily by ISPs,
business, and other large enterprises to connect LANs and
campus networks to the Internet using the existing
infrastructure of the public telephone network or other
providers.
Delivered using wire, optical fiber, and radio, leased lines are
used to provide Internet access directly as well as the building
blocks from which several other forms of Internet access are
created.

Slide No. 5 of 45
Narrowband Vs Broadband
Type of
Connection
Dialup-
PSTN
Dialup-
ISDN
Leased
Line
Broadband
Speed 64Kbps 128Kbps 64Kbps to
10Mbps
>256Kbps
Availability Anywhere ISDN
supported
switches
Anywhere Anywhere
Internet Access Dial &
connect
Dial &
connect
Always ON Always ON

Slide No. 10 of 45
DIGITAL SUBSCRIBER LINE (DSL)
Digital Subscriber line (DSL) is a wireline
transmission technology that brings information
faster over copper telephone lines already
installed in homes and business.
DSL exploits "extra capacity" to carry information
on the wire without disturbing the line's ability to
carry conversations.

11
DSL Technology
DSL may offer more than 100 times the network
performance of a traditional analog modem
Precise speed of a connection depends upon
the type of DSL employed
DSL uses the same telephone line as traditional
modem
Provides simultaneous access to Web &
Telephone removing the need for a second
telephone line.
© BHARAT SANCHAR NIGAM LIMITED Slide No. 13 of 45

12
DSL Technology
DSL remains always-on all the time
➢Customers no longer need to physically dial up to the ISPto
“log in to the internet”
On power failure, telephone line is still available like a
standard telephone line.

xDSL Family Tree
xDSL
➢Symmetric DSL
• Provide identical data rates upstream & downstream
➢Asymmetric DSL
• Provide relatively lower rates upstream but higher ratesdownstream
Four main variations of xDSL exist:
➢ADSL-Asymmetrical Digital Sub’s Line
➢HDSL-High bit/data rate Digital Sub’sLine
➢SDSL-- Symmetric Digital Sub’sLine
➢VDSL-Very-high-data-rate Digital Sub’s Line
13
Slide No. 13 of 45

Slide No. 14 of 45
ADSL
Asymmetrical Digital Subscriber Line
Used primarily by residential users who receive a lot
of data but do not send much such as Internet
surfers.
ADSL provides faster speed in a downstream
direction (from the ISP office to the customer
premises) than the upstream direction (i.e from
customer premises to ISP office)

15
ADSL
Asymmetric Digital Subscriber Line
G.DMTG.992.1 standard
Used for applications which require greater download
bandwidth but require relatively little in opposite
direction like Web browsing.
An ADSL circuit connects an ADSL modem on one end
of a twisted pair telephone line creating three
information channels
➢A high speed downstream channel
➢A medium speed duplex channel for both upstream&
downstream applications
➢A basic telephone service channel

Frequency
(KHz)
Voice
0 4 25 138 139
No
of
Bits
15
1104 KHz
6 37
Upstrea
m
Downstrea
m
38 255
ADSL
0
GB
Slide No. 18 of 51

16
ADSL
The basic telephone service channel is split off from
the digital modem by splitter at client site.
Allows simultaneous access of the line by the
telephone and the computer.
In case of power/ADSL failure, data transmission is
lost but basic telephone service will be
operational.
Can work up to a distance of 3.7 to 5.5 kms.

Slide No. 17 of 45
ADSL STANDARDS
Family Down stream Maximum
ADSL
Up stream
Rate
Rate range
5.5 Km
640 kbps 8 Mbps
ADSL2
12-16 Mbps 5.7 Km
1-1.5 Mbps
ADSL2 + 1 Mbps 26 Mbps 5.7 Km

ADSL
Family Description Upsteream
Rate
Down
stream
Rate
Max.
range
ADSL G,992.1 / G.DMT 640 KBps 8 MBps 5.5 Km June
1999
ADSL Lite G.992.2 / G.Lite 384 KBps 2 MBps 6Km
ADSL2 G.992.3 / G.dmt.bis 1-1.5 MBps 12-16
MBps
5.7 Km July
2002
ADSL2 Lite G.992.4 / G.lite.bis
ADSL2 + G.992.5 / ADSL 2 plus 1 MBps 26 MBps 5.7 Km May
2003
ADSL2 RE G.992.3 Reach Extended 1MBps 12 MBps 7Km
21
Slide No. 18 of 45

ADSL 2
Second generation of ADSL
G.DMT.bis or G.992.3 standard
Offers a greater data rates of 15 Mb/s downstream and
upto 1.5 Mb/s upstream with a range 6.4 Kms
Has two power management modes ( L2 mode for
power saving at ATU-C by rapidly entering and exiting
low power mode based on internet traffic over the
connection)and L3 mode for overall power saving at
both ATU-C and ATU-R by entering into sleep mode) that
help reduce power consumption
22
Slide No. 18 of 45

ADSL 2…contd.
Supports seamless adaptation of data rate in
real time to meet the changing line conditions
Fast start up i.e. Reduced initialization time
from 10 secs to 3 secs.
Data rates can be increased by bonding
multiple phone lines ( 2 or more copper pairs)
together.
23
Slide No. 18 of 45

ADSL 2 +
Second generation of ADSL
G.992.5 standard
Doubles max. frequency used for down stream data
transmission from 1.1 Mhz to 2.2 Mhz.
Offers a greater data rates of 25 Mb/s downstream and
upto 1.5 Mb/s upstream.
Can work upto 6.3 Kms with reduced data rates.
Has all the other benefits of ADSL 2 like improved power
management , seamless adaptation of data rate
in real time to meet the changing line conditions, bonding
of copper pairs for higher data rates etc.
24
Slide No. 18 of 45

Slide No. 22 of 45
EFFECT OF COPPER PAIR QUALITY
Data speed capability depends on the thickness
of wire used in cable network.
Higher
speed.
the gauge, higher the data carrying
Data speed deteriorates if copper loop quality is
bad i.e. more joints, loose joints, low insulation
etc.

Data Rate - Wire Size – Distance
Wire Diameter Vs Speed Vs Distance in ADSL
Data Rate Wire Size Distance
1.5-2.0 Mbps 0.5 mm 18000 Feet 5.5 Kms
1.5-2.0 Mbps 0.4 mm 15000 Feet 4.6 Kms
6.1 Mbps 0.5 mm 12000 Feet 3.7 Kms
6.1 Mbps 0.4 mm 9000 Feet 2.7 Kms

ADSL APPLICATIONS
Internet access ( SOHO)
LAN Access (Telecommuting)
Distance Learning
Tele-medicine
Broadcast TV
Home shopping
Interactive Games
Movies
27
Slide No. 23 of 45

Slide No. 25 of 45
SDSL
Symmetrical Digital Subscriber Line
Used typically for business applications
video conferencing.
such as
The data rate in both directions is equal.

Slide No. 26 of 45
HDSL
High Data Rate Digital Subscriber Line
Provides fixed symmetrical high-speed access
rate (1.5 Mbps) or E1 rate (2.048Mbps)
Designed for business purposes
at T1

Slide No. 27 of 45
VDSL
Very High Data Rate Digital Subscriber Line
Provides both symmetrical and asymmetrical access with very high bit
rate over the copper line.
Very-high-bit-rate digital subscriber line (VDSL or VHDSL, provides data rates up
to 52 Mbit/s downstream and 16 Mbit/s upstream over copper wires and up to
85 Mbit/s down- and upstream on coaxial cable.
VDSL is capable of supporting applications such as high-definition television, as
well as telephone services (voice over IP) and general Internet access, over a
single physical connection.
The maximum data rate is achieved at a range of about 300 meters and
performance degrades as distance and loop attenuation increases.

Cable Modem
There are 3 types of cable modem:-
1) External Cable Modem
• External box connected to computer through Ethernet connection
• Can use USB interface too.
2) Internal Cable Modem
• Is typically a PCI bus add-in card for a PC
3) Interactive Set-Top Box
• Provides a return channel –often through the POTS-giving access to
web browsing through the TV screen.

Disadvantages of Cable Modem
• Bandwidth Sharing: Users in a neighborhood have to share the
available bandwidth provided by a single coaxial cable line. Therefore,
connection speed can vary depending on how many people are using
the service at the same time. Often the idea of a shared line is seen as a
weak point of cable Internet access.
• Security: A more significant weakness of cable networks using a
shared line is the risk of loss of privacy, especially considering the
availability of hacking tools for cable modems.
• Connectivity Problem :Many cable Internet providers are reluctant to
offer cable modem access without tying it to a cable television
subscription.
• Cost factor: The cost of Cable modem & splitters is high as complared
to ADSL modems.

Slide No. 9 of 45
ADSL Broadband Vs Cable Modem Service
ADSL Access Cable Modem Access
ADSL Access provides
dedicated connection to home
Cable Modem (internet service
given by Cable TV operators)
offers shared bandwidth.
Speed is asymmetric Speed is asymmetric
Performance of DSL based
service depends on the distance
between end user and phone
company central office
Speed will vary depending on
the number of people on the
network.

Power Line Communication (PLC)
PLC also called Broadband over Power Lines (BPL) or Power Line Telecoms
(PLT), is a wireline technology that is able to use the current electricity
networks for data and voice transmission.
The carrier can communicate voice and data by superimposing an analog
signal over the standard 50 or 60 Hz alternating current (AC).
Traditionally electrical utilities use low-speed power-line carrier circuits
for control of substations, voice communication, and protection of high-
voltage transmission lines.
More recently, high-speed data transmission has been developed using
the lower voltage transmission lines used for power distribution.
A short range form of power-line carrier is used for home automation
and intercoms.A computer (or any other device) would need only to plug
a BPL "modem" into any outlet in an equipped building to have high-
speed Internet access.

PLC
The asymmetric speed in the modem is generally from 256 kbit/s to 2.7
Mbit/s.
In the repeater situated in the meter room the speed is up to 45 Mbit/s
and can be connected to 256 PLC modems.
In the medium voltage stations, the speed from the head ends to the
Internet is up to 135 Mbit/s.
To connect to the Internet, utilities can use optical fiber backbone or
wireless link.

PLC
PLC uses the following frequencies bands.
Low frequencies
• Below 400 kHz (US)
• Below 125 kHz (Europe)
• Transmission rate about 1 to 10 kbps
Low Band is used for Telemetry,Security & Remote Control.
High frequencies
• 2 to 30 MHZ (HF)
• Transmission rate about 1 to 40 Mbps
High Band is used for Telephony & Internet.

Advantages
The major advantage of BPL over regular cable
or DSL connections is the availability of the
extensive infrastructure already available which
would appear to allow more people in more
locations to have access to the Internet.

Disadvantages
1. Network characteristics (topology, impedance) and devices
(regulators, capacitors) can adversely affect signal strength and
quality.
2. Electronic loads and nearby high frequency radiation sources may
cause high frequency noise that interferes with BPL.
3. Equipment will be exposed to severe lightning and switching surges.
4. Utility operations and maintenance personnel may damage or
improperly install equipment.
5. Some of the PLC systems are not fully operable at very low or no
load without battery backup.

OPTIC FIBER TECHNOLOGIES
Currently fiber costs are high as compared to copper but there is a trend
towards decreasing costs of optical fiber cables.
Its small weight and size over copper cable are making it a very
attractive technology to replace copper in subs loop when advanced
broadband services need to be offered to the customer.
To carry the same information as one fiber cable we would need
hundreds of reels of twisted wire Cu cables.
Further, fiber is 23 times lighter than Cu cable and 36 times less in cross-
sectional area.
These features of light weight and small size make it easier to handle
fiber cable.
In crowded city networks they can easily be accommodated in existing
ducted systems.

Fiber in loop (FITL) can be developed in several
configurations.
• Fiber to the Curb(FTTC)
• Fiber to the building(FTTB)
• Fiber to the home/Office(FTTH/FTTO)

Fibre to the Curb(FTTC)
In FTTC terminal equipment is located on the curb from where
it would be convenient to serve a suitable service area.
Since the distribution would still be copper, suitable location
for the terminal would be one which optimizes the cost,
reduces back-feeding, reduces distribution cost and takes
safety factors into consideration.
Space and power availability need to be confirmed before
finalising the location.

Fibre to the building(FTTB)
In FTTB, terminal equipment is located inside a multistoreyed
building.
This brings higher bandwidth closer to the subscriber.
The distribution part is still copper.
For new buildings, the planners may negotiate for suitable
location well in time.

Fibre to the home/Office (FTTH/FTTO)
In this method the fiber goes upto the
subscriber premises.

Slide No. 46 of 45
High Speed, Always-on Internet Access Content
Based Services
Video on Demand
Education
Audio on Demand
Web conferencing
Interactive Gaming
Multiplay Services
VPN on broadband
or Games on Demand
BSNL BROADBANDSERVICES

Slide No. 47 of 45
DO'S AND DON’TS
No phone/Fax should be connected before splitter.
Change your password regularly
Remember or write down your password after every
change of password.
Check your usages detail regularly..
Surfing, Listening Live Music, Chatting, Online
Gaming, Internet Telephony, E-mail, Anti-virus and
any other software updates through Internet etc. all
are part of download/upload.

Slide No. 48 of 45
DO'S AND DON’TS
Keep automatic updates disabled on your computer
Clean your computer virus regularly.
Log off from broadband connection and switch off
modem when not in use.
Do not disclose your broadband User ID and
Password to anybody.

Slide No. 49 of 45
SPEED CHECK
Customer is assured of promised speed.
Customer can check speed for their connection at link
http://www.speedtester.bsnl.co.in/
The check is performed by measuring the speed of a
file transfer.

Slide No. 50 of 45
DATA USAGE
It is the aggregate of data uploaded and downloaded
through broadband connection.
The Data Usage is accounted in GB (Giga Bytes).
A customer if subscribed for Games on demand or
other services ,the data usage is normally not
charged separately

Line Parameters for Broadband
1. The loop resistance should be less than 1100 ohms.
2. Insulation resistance between the a limb and b linb, a limb
to earth & b limb to earth should be more than 2
Megaohms .
3. Wires should not contain any joints.
4. The foreign potential between a limb to earth & b limb to
earth should be less than 6 volts.
5. There should not be any cross talk in the line.
6. There should not be any noise in the line.
7. Usage of drop wire should be minimum
8. The capacitance excluding the instrument should be
inbetween 0.3 to 0.5 microfarads.

Broadband network overview bsnl industrial training engineering

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