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Digital Subscriber Line(DSL)

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xDSL Family Tree

xDSL

Symmetric DSL

Provide identical data rates upstream &downstream

Asymmetric DSL

Provide relatively lower rates upstream but higherrates downstream

Four main variations of xDSL exist:

ADSL-Asymmetrical Digital Subs Line HDSL-High bit/data rate Digital Subs Line

VDSL-Very-high-data-rate Digital Subs Line

IDSL-ISDN Digital Subs Line

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ADSL

Asymmetric Digital Subscriber Line

Used for applications which require greaterdownload bandwidth but require relatively little in

opposite direction like Web browsing; Filedownloads

An ADSL circuit connects an ADSL modem oneach end of a twisted pair telephone line creatingthree information channels

A high speed downstream channel

A medium speed duplex channel

A basic telephone service channel

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ADSL

Allows simultaneous access to theline by the telephone and the

computer In case of power/ADSL failure, data

transmission is lost but basictelephone service will be operational

Can work up to a distance of 3.7 to5.5 kms depending upon the speedrequired

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Data Rate - Wire Size Distance

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

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RADSL

Rate-Adaptive DSL

Is a form of ADSL

Automatically configures themodem at startup to adjust its rateaccording to the quality of phoneline

Supports a maximum of 1088 kbps

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ADSL Deployment Today

Central OfficeHome/Office

ADSL

CPE

Curb

ADSL up to 5Km

SHDSL (PAM16) up to 5KmSHDSL

Splitter

DSLAM

Data switch

Voice Switch

POTS

2 wire

2 wire

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DSL Technologies Evolution of

Network

Central OfficeHome/Office

ADSL

CPE

C r

ADSL up to 5Km

SHDSL (PAM16) up to 10KmSHDSL

IAD

VDSL

IAD

S litter ONU OLT

DSLAM

VDSL up

to 1.5Km

Fiber

VoDSL

VOICE

Fiber

Multicast

TV

S litter

4-wire

SHDSL

Voice SwitchIP Phone

POTS

IP Phone

POTS

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HDSL

High bit/data rate DSL

Can be viewed as equivalent of PCM stream

Offers the same bandwidth both upstreamand downstream

Can work up to a distance of 3.66 to 4.57kms depending upon the speed required

Can deliver 2048 kbps On 2 phone lines, each line carrying 1168 kbps

On 3 phone lines, each line carrying 784 kbps

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HDSL

No provision exists for voice becauseit uses the voice band

HDSL-2 is proposed as nextgeneration HDSL over single phoneline

Requires more aggressivemodulation, shorter distance andbetter phone line

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SDSL

Symmetric Digital Subscriber Line

Rate adaptive version of HDSL

Does not support analog calls

Works up to 3.7 kms on 0.5 mm dia cable Affordable alternative to dedicated leased

lines

SHDSL-Symmetric High-bit-rate Digital

Subscriber Line is an further improvementover HDSL/SDSL and uses single phoneline

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VDSL

Very-high Data-rate DSL

Also known as BDSL

Originally named VADSL (A Asymmetric) but was later extended tosupport both symmetric & asymmetric

Requires one phone line

Supports voice & data Works between 0.3-1.37 kms depending

on speed

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Upstream data rate of 1.6-2.3 mbps

Downstream data rate of 13-52 mbps

Data Rate - Wire Size Distance

VDSL

Downstream Upstream Distance

12.96 Mbps 1.6-2.3mbps

4500 Feet 1.37 Kms

25.82 Mbps 1.6-2.3mbps

3000 Feet 0.91 Kms

51.84 Mbps 1.6-2.3mbps

1000 Feet 0.30 Kms

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IDSL

ISDN DSL-a hybrid DSL/ISDN solution

Works over existing ISDN connection

Increases ISDN speed from 128 kbps to144 kbps

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What is a Cable Modem?

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PLC

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The Distribution System

Insert Power Line

Carrier at middle

voltage

Backhaul to NAP

(fiber, DSL, wireless,

satellite)

Gettingbeyond thetransformer

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Requirement at Customer End

BSNLs BFone

Computer of minimum configuration, with

10/100 Mbps Ethernet Card

DSL Modem + Splitter

PPPoE software to be loaded in the Client

Broadband Account (Username and Password)

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UT- 300R ADSL CPE

Product Features

One RJ 45 andOne RJ-11 ports available

Supports ANSI T1.413, G.DMT and G.LITE

Supports swappable Bridge and Router

mode

Supports IP routing and NAT/NAPT function

Supports DHCP server anddynamic

allocation ofIP address

Built-inIP filter and access logsHigh reliability, easy operation and low power

consumption

Web based configuration and monitoring

Interoperable with other DSLAM

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How to connect Multiple Telephones

(1) Phone Socket

(2)&(3) Phone

(4) ,(6)& (7)

RJ-11 Tel cable

(5) Splitter

(8) Phone Jack

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highpass

filterLINEDSL

lowpassfilter

TELE

Circuit Diagram of A POTS Splitter

Splitter

Separates the 300 Hz to 3500 Hz voicechannel from upstream anddownstream channels

Reduces traffic congestion

Pass voice, dial tone, ringing and

on/off hook signals Consists of a lowpass filter (LPF) for

POTS and a highpass filter (HPF) forupstream/downstream channels

Passive device

Contains lighting protection circuitry

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CPE Installation

BRAS

CPE

PPPoE Session

T2 Switch

T1 Switch

BRAS

CPE

PPPoE Session

T2 Switch

T1 Switch

Bridge Mode

DSLAM

IP Address is allocated

to PC ByBRAS

Router ModeIP Address isallocated to CPE

ByBRAS

IP Address is

allocated

to PC By CPE

NATDSLAM

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Multi User Customer

BRAS

CPE

T2 Switch

T1 Switch

Bridge Mode

DSLAM

IP Address is allocated

to PCs ByBRAS

Multi User Customer

If a user is allowed to login multiple sessions with

BRAS with same password, every machine esta lishesa separate PPPoE Session with BRAS. Every machine

Gets full andwidth for that account provided CPE -

DSLAMLink supports that.

Switch

ADSL Port on DSLAM Should

allow that many MAC addresses

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Multi User Customer

BRAS

CPE

T2 SwitchT1 Switch

Router Mode

DSLAM

IP Address is allocated

to PCs By CPE

Multi User Customer

In this mode PPPoE is configured on CPE and only

One session is esta lished etween CPE and BRAS.

CPE gets IP Address from BRAS. DHCP in CPE

Allocates IP addresses to machines. In this case all

The machines share the andwidth allowed for that

Account. CPE has to do NAT also.

Switch PPPoE Session

NAT

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IP DSLAM

P-Slot

PCU

ICMSlots

UniversalSlots (1 16)

116 B A

Fan Fuses

Power In

Chassis Ground

Ext. Alarm

Integrated

Splitter Shelf

Fan Fuses

Power In

Chassis Ground

Ext. Alarm

Integrated

Splitter Shelf

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DSL Technologies

Technology ITU-TStandard

Distance Downstream

Data Rate

Upstream

Data Rate

ADSL G-992.1 3.5 Kms 8 Mbps 640 Kbps

Splitterless ADSL G-992.2 4.0 Kms 1.5 Mbps 512 Kbps

ADSL-

Extended Bandwidth

G-992.5 1.5 Kms 16 Mbps 100 Kbps

2 Wire High-Speed DSL G-991.2 3.0 Kms 2312 Kbps 2312 Kbps

4 Wire High-Speed DSL G-991.2 3.0 Kms 4624 Kbps 4624 Kbps

Very High-speed DSL G-993.1 300 Mts 52 Mbps 6-26 Mbps

Very High-speed DSL G-993.1 700 Mts 26 Mbps 26 Mbps

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NIB-II Broadband DSL Deployment

Normal Line

Ex Side Line SideMDF

InternetGE/FE

Normal Line

DSL Line

Normal Line

Normal Line

Normal Line

DSL Line

DSL Line

Telco Switch

DSLAM

POTS Line

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Customer Premises Installation

Splitter ADSLRJ 11 RJ 11

RJ 11

RJ 11

RJ 45

Line

Single User with

Voice and Data

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Customer Premises Installation

Splitter ADSL

STB

RJ 11 RJ 11

RJ 11 RJ 45 RJ 45

RJ 45

AV Port

Single User with

Voice, Data and Video

Line RJ 11

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Customer Premises Installation

Splitter ADSL

Switch

Multi user Business

Customer

Line

RJ 11 RJ 11

RJ 11

RJ 45

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ADSL POTS Splitter

DSLHigh pass

filter

Low pass

filter

Telephone

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