ADSL ASYMMETRIC DIGITAL SUBSCRIBER LINE

Transkripsi

1 ADSL ASYMMETRIC DIGITAL SUBSCRIBER LINE

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 Konfigurasi dasar ADSL

4 ADSL Cara kerja 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 highpass filter.

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 Sebagai internet 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 Radius 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 ADSL is now available in every region of the world

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 pair copper loop to the subscriber premises

15 ADSL standards : Standard name ITU G ITU G ITU G.992.3/4 Common name ADSL (G.DMT) Downstream rate Upstream rate 8 Mbit/s 1.0 Mbit/s ADSL Lite (G.Lite) 1.5 Mbit/s 0.5 Mbit/s ADSL2 12 Mbit/s 1.0 Mbit/s ITU G.992.3/4 Annex J ITU G.992.3/4 Annex L ITU G ITU G Annex L ITU G Annex M ADSL2 RE-ADSL2 ADSL2+ RE-ADSL2+ ADSL2+ 12 Mbit/s 3.5 Mbit/s 5 Mbit/s 0.8 Mbit/s 24 Mbit/s 1.0 Mbit/s 24 Mbit/s 1.0 Mbit/s 28 Mbit/s 3.5 Mbit/s

16 ADSL Speed Comparison Pure Fibre Hybrid Fibre/Copper FTTH Enhanced Copper ADSL FTTx, VDSL2, ADSL2plus Voice band Modem ISDN

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 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 1.5 or 2 Mbps 26 AWG 0.4 mm 2.7 For larger distances, you may be able to have DSL if your phone company has extended the local loop with optical fiber cable

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 The proximity of the wires to radio transmitters.

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 Voice Switch DSL ISP Central Office Subscriber premises

21 ADSL Requirements Phone-line, activated by your phone company for ADSL Filter to separate the phone signal from the Internet signal ADSL modem Subscription with an ISP supporting ADSL

22 How does ADSL work ADSL exploits the unused analogue bandwidth available in the wires PSTN Upstream Downstream 4 25, KHz ADSL works by using a frequency splitter device to split a traditional voice telephone line into two frequencies

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) Discrete Multi-Tone (DMT)

24 Carrierless Amplitude Phase Carrierless Amplitude Phase (CAP) is an encoding method that divides the signals into two distinct bands: 1. The upstream data channel (to the service provider), which is carried in the band between 25 and 160kHz 1. 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 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 kHz 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) Echo Cancellation

27 ADSL Protocol stacks Ethernet over ATM (EoA) IP over ATM (IPoA) PPP over ATM (PPPoA) PPP over Ethernet (PPPoE) Native ATM

28 Point-to-Point Protocol over Ethernet over ATM (PPPoEoA)

29 Conclusion: Pros & Cons Why ADSL? Simultaneous Internet and voice/fax capabilities over a single telephone line Uninterrupted, high-speed Internet access that's always on-line Cost-effective solution for society Data Security that exceeds other technologies Fast download speeds ADSL disadvantages: Distance-sensitive Slower upload speeds Phone line required