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CLI-based Configuration Guide - Interface Management

AR100, AR120, AR160, AR1200, AR2200, AR3200, and AR3600 V300R003

This document provides the basic concepts, configuration procedures, and configuration examples of the interfaces supported by the device.
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Huawei uses machine translation combined with human proofreading to translate this document to different languages in order to help you better understand the content of this document. Note: Even the most advanced machine translation cannot match the quality of professional translators. Huawei shall not bear any responsibility for translation accuracy and it is recommended that you refer to the English document (a link for which has been provided).
Overview of ADSL Interfaces

Overview of ADSL Interfaces

ADSL is a data communications technology that enables fast data transmission over copper twisted pairs by employing high frequencies that are not used by regular telephone lines.


Users must access networks to use Internet services. Varying with transmission media, network access modes include wired access, wireless access, and combination of wired and wireless access. Wired access includes copper access, fiber access, and access by using both twisted pairs and fibers. Copper twisted pair access is widely used currently, so ADSL becomes the most competitive access mode.

ADSL uses frequency division multiplexing (FDM) technology to classify telephone lines into regular telephone lines, upstream channels, and downstream channels to avoid interference. ADSL can provide channelized data services (including E1/Tl, FR, IP, and ATM services) and transmit data, voice, and video signals at a high rate.

ADSL Evolution

The first ADSL standards (G.992.1 G.DMT and G.992.2 G.Lite) supported the upstream transmission rate of 640 kbit/s to 2 Mbit/s, downstream transmission rate of 1 Mbit/s to 8 Mbit/s, and transmission distance of 3 to 5 km. Since the release of ADSL in June 1999, the ITU-T has been improving the ADSL transmission performance, anti-attenuation and anti-interference capabilities, line diagnosis, and operation maintenance. In 2002, the ITU-T released ADSL2, which comprises two new ADSL standards (G.992.3 and G.992.4). In 2003, the ITU-T defined G.992.5, which is referred to as ADSL2+.

Compared with the first ADSL technology, ADSL2/2+ has the following advantages:

  1. ADSL2 improves performance in long-distance transmission, anti-attenuation, and anti-noise. ADSL2 also improves the frame structure, so it can provide a maximum of 1 Mbit/s upstream transmission rate and 12 Mbit/s downstream transmission rate. Expanding the frequency spectrum used, ADSL2+ greatly improves transmission performance and provides a maximum rate of 1 Mbit/s upstream and 24 Mbit/s downstream.
  2. In addition to providing higher rates, ADSL2/2+ improves transmission performance in long-distance transmission and anti-interference by improving the modulation rate and coding gain, reducing the frame overhead, and using enhanced signal processing methods. Currently, ADSL provides a transmission distance of 3 km, whereas ADSL2+ achieves a maximum of 6 km transmission distance.
  3. ADSL2/2+ saves energy. The first ADSL technology provides the same transmission rate regardless of whether data is being transmitted. ADSL2/2+ enables a transmitter to enter the sleep state when the data transmission rate is low or no data is being transmitted, reducing power consumption and heat dissipation.

ADSL System

As shown in Figure 16-1, an ADSL system consists of a Digital Subscriber Line Access Multiplexer (DSLAM) and Customer Premises Equipment (CPE).
  • A DSLAM is an aggregation device that terminates ADSL packets on the central office.
  • A CPE provides interfaces for users, modulates and demodulates data signals, and uploads user data to a DSLAM.

A router functions as a CPE.

In the ADSL system, downstream transmission refers to data transmission from a DSLAM to a CPE, and upstream transmission refers to data transmission from a CPE to a DSLAM. ADSL interfaces on the device are upstream interfaces.

Figure 16-1  ADSL system

Service Supported by an ADSL Interface

This section provides only the physical attribute configuration of ADSL interfaces. For details about ATM service configuration including the PVC configuration, see ATM Configuration in the Configuration Guide - WAN.

Updated: 2019-03-06

Document ID: EDOC1100069331

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