ADSL ASYMMETRIC DIGITAL SUBSCRIBER LINE

(1)

ASYMMETRIC DIGITAL SUBSCRIBER LINE ASYMMETRIC DIGITAL SUBSCRIBER LINE

ADSL

(2)

ADSL

•ADSL (Asymmetric Digital Subscriber Line) : teknologi akses, yang memungkinkan terjadinya

komunikasi data, voice dan video secara bersamaan, menggunakan media jaringan akses kabel tembaga 1 pair.

•Disebut asimetrik karena rate / kecepatan transmisi dari sentral ke pelanggan (dowstream) tidak sama

dengan rate transmisi dari arah pelanggan ke sentral (upstream)

•Bit rate downstream  8 Mb/s, upstream  640 kb/s

•Aplikasi ini digunakan untuk menyalurkan layanan broadband

(3)

ADSL

(4)

ADSL

(5)

ADSL

Komponen pembangun ADSL :

•Modem ADSL •Splitter •DSLAM •Remote DSLAM •ATM Switch •BRAS •RADIUS •NMS

(6)

ADSL

•Modem ADSL merupakan perangkat di sisi

pelanggan/client sehingga data digital dapat

diterima dan dikirimkan melalui kabel telepon,

atau berfungsi sebagai pengubah sinyal analog

to digital atau sebaliknya. Beberapa merek

modem sering dipakai diantaranya : Alcatel,

ZTE, Huawei, Dear Global, Allied Telesyn,

Ericsson, dsb.

(7)

ADSL

•Splitter berfungsi sebagai pemisah/pengenal

antara sinyal analog (voice) ataukah data. Jika

yang datang adalah voice, maka informasi

tersebut akan diteruskan ke telepon. Jika yang

datang adalah data, maka informasi tersebut

akan diteruskan ke modem untuk selanjutnya

ke computer. Prinsip kerja dari splitter adalah

menggunakan filter, Lowpass filter dan

(8)

ADSL

•_{DSLAM Adalah Konfigurasi perangkat xDSL yang secara fisik} modem sentralnya berupa card module yang berisi banyak modem sentral.

•Fungsi DSLAM diantaranya :

• _{Sebagai filter Voice dan Data}

• Sebagai Modulator / Demodulator DSL • Sebagai Multiplexer (Sebagai ATM )

• VP Multiplexing • _{VC Multiplexing}

• _{Traffic management} • OAM Functionality

(9)

ADSL

•_{REMOTE DSLAM, Merupakan DSLAM yang dipasang} didaerah yang jauh/terpencil tetapi dimungkinkan banyak

pelanggan yang menggunakan fasilitas ADSL. Kapasitas dari Remote DSLAM ini biasanya tidak terlalu besar.

•ATM Switch

Fungsi ATM Switch adalah :

• _{Titik penyambungan/}_switching₍_{cross connect}_{) antara} DSLAM dan RAS

• Sebagai gateway jaringan ATM

• _Multiplexer_{paket ATM dari DSLAM} • Titik interkoneksi antara ATM dan IP

(10)

ADSL

•BRAS

Broadband Remote Access Service berfungsi : • Melakukan routing dari user ke ISP tujuan

• IP management

• Konfigurasi interface user

• Sebagai ISP gateway

(11)

ADSL

•RADIUS

Fungsi RADIUS adalah :

• Authentication → mengidentifikasi user melalui

user name, password, calling number

• Authorization→ melayani akses user sesuai dengan service level nya (LDAP)

• Accounting → melakukan proses billing and informasi penggunaan seorang user

(12)

ADSL

•NMS

Network Management Sistem berfungsi : • DSLAM management

• Monitoring status/kondisi DSLAM • Buka/tutup port pelanggan

• Setting speed pelanggan

• Monitoring status/kondisi modem pelanggan • ATM Switch management

• BRAS management

(13)

Introduction

ADSL is a form of DSL, a data communications technology

that enables faster data transmission over copper telephone lines

ADSL is capable of providing up to 50 Mbps, and supports

voice, video and data.

ADSL is the #1 Broadband Choice in the World with over

60% market share

(14)

What does ADSL mean

Asymmetric - The data can flow faster in one direction

than the other. Data transmission has faster downstream to the subscriber than upstream

Digital - No type of communication is transferred in an

analog method. All data is purely digital, and only at the end, modulated to be carried over the line.

Subscriber Line - The data is carried over a single twisted

(15)

ADSL standards :

Standard name

Standard name Common name Common name Downstream Downstream rate rate Upstream Upstream rate rate ITU G.992.1

ITU G.992.1 ADSL (G.DMT) ADSL (G.DMT) 8 Mbit/s 8 Mbit/s 1.0 Mbit/s 1.0 Mbit/s ITU G.992.2

ITU G.992.2 ADSL Lite (G.Lite) ADSL Lite (G.Lite) 1.5 Mbit/s 1.5 Mbit/s 0.5 Mbit/s 0.5 Mbit/s ITU G.992.3/4

ITU G.992.3/4 ADSL2 ADSL2 12 Mbit/s 12 Mbit/s 1.0 Mbit/s 1.0 Mbit/s ITU G.992.3/4 Annex J

ITU G.992.3/4 Annex J ADSL2 ADSL2 12 Mbit/s 12 Mbit/s 3.5 Mbit/s 3.5 Mbit/s ITU G.992.3/4 Annex L

ITU G.992.3/4 Annex L RE-ADSL2 RE-ADSL2 5 Mbit/s 5 Mbit/s 0.8 Mbit/s 0.8 Mbit/s ITU G.992.5

ITU G.992.5 ADSL2+ ADSL2+ 24 Mbit/s 24 Mbit/s 1.0 Mbit/s 1.0 Mbit/s ITU G.992.5 Annex L

ITU G.992.5 Annex L RE-ADSL2+ RE-ADSL2+ 24 Mbit/s 24 Mbit/s 1.0 Mbit/s 1.0 Mbit/s ITU G.992.5 Annex M

(16)

ISDN ADSL FTTx, VDSL2, ADSL2plus Enhanced Copper Hybrid Fibre/Copper Pure Fibre

ADSL Speed Comparison

Voice band Modem

(17)

ADSL Range

In general, the maximum range for DSL without a repeater

is 5.5 km

As distance decreases toward the telephone company office,

the data rate increases

For larger distances, you may be able to have DSL if your

phone company has extended the local loop with optical fiber cable

Data Rate Wire gauge Wire size Distance

1.5 or 2 Mbps 24 AWG 0.5 mm 5.5 km

1.5 or 2 Mbps 26 AWG 0.4 mm 4.6 km

6.1 Mbps 24 AWG 0.5 mm 3.7 km

(18)

ADSL Speed Factors

The distance from the local exchange The type and thickness of wires used

The number and type of joins in the wire

The proximity of the wire to other wires carrying ADSL,

ISDN and other non-voice signals

(19)

ADSL network components

The ADSL modem at the customer premises(ATU-R) The modem of the central office (ATU-C)

DSL access multiplexer (DSLAM) Broadband Access Server (BAS)

Splitter - an electronic low pass filter that separates the

analogue voice or ISDN signal from ADSL data frequencies DSLAM.

(20)

ADSL Loop Architecture

ISP

Central Office _{Subscriber premises} Voice Switch

(21)

ADSL Requirements

Phone-line, activated by your phone company for ADSL

Filter to separate the phone signal from the Internet signal ADSL modem

(22)

How does ADSL work

ADSL exploits the _{ADSL exploits the}unused analogue bandwidth _{unused analogue bandwidth}

available in the wires available in the wires

ADSL works by using a frequency splitter device to split a _{ADSL works by using a frequency splitter device to split a}

traditional voice telephone line into two frequencies traditional voice telephone line into two frequencies

4 25,875 138 1104 KHz

PSTN

(23)

ADSL Modulation

Modulation is the overlaying of information (or the signal)

onto an electronic or optical carrier waveform

There are two competing and incompatible standards for

modulating the ADSL signal:

 Carrierless Amplitude Phase (CAP)

(24)

Carrierless Amplitude Phase

 Carrierless Amplitude Phase (CAP) is an encoding _{Carrierless Amplitude Phase (CAP) is an encoding}

method that divides the signals into two distinct bands: method that divides the signals into two distinct bands:

1.

1. The upstream data channel (to the service provider), which is The upstream data channel (to the service provider), which is

carried in the band between 25 and 160kHz

1.

1. The downstream data channel (to the user), which is carried in The downstream data channel (to the user), which is carried in

the band from 200kHz to 1.1MHz .

 These channels are widely separated in order to _{These channels are widely separated in order to}

minimize the possibility of interference between the minimize the possibility of interference between the channels.

(25)

Discrete Multi-tone (DMT)

Discrete Multi-Tone (DMT) separates the DSL signal so

that the usable frequency range is separated into 256 channels of 4.3125kHz each.

DMT has 224 downstream frequency bins (or carriers) and

32 upstream frequency bins.

DMT constantly shifts signals between different channels

to ensure that the best channels are used for transmission and reception.

(26)

The DMT frequency bands

_{Frequency Division Multiplexing (FDM)}

(27)

ADSL Protocol stacks

Ethernet over Ethernet over ATM (EoA) ATM (EoA) IP over ATM IP over ATM (IPoA) (IPoA) PPP over ATM PPP over ATM (PPPoA) (PPPoA) PPP over Ethernet PPP over Ethernet (PPPoE) (PPPoE) Native ATM Native ATM

(28)

Point-to-Point Protocol over Ethernet over ATM

(PPPoEoA)

(29)

Conclusion: Pros & Cons

Why ADSL?Why ADSL?

 Simultaneous Internet and voice/fax capabilities over a Simultaneous Internet and voice/fax capabilities over a

single telephone line

 Uninterrupted, high-speed Internet access that's always Uninterrupted, high-speed Internet access that's always

on-line

 Cost-effective solution for societyCost-effective solution for society

 Data Security that exceeds other technologies Data Security that exceeds other technologies

 Fast download speedsFast download speeds

ADSL disadvantages:ADSL disadvantages:

 Distance-sensitiveDistance-sensitive

 Slower upload speedsSlower upload speeds