What is xDSL technology and what does xDSL mean?

XDSL is a general term for DSL (Digital Subscriber Line), which means digital subscriber line, which is a point-to-point transmission technology with copper wire as the transmission medium. DSL technology supports symmetric and asymmetric transmission modes on the user loop of traditional networks (POTS), which solves the problem that often occurs between network service providers and end users"The last mile"transmission bottlenecks. Since a large number of user loops have been laid, making full use of existing copper cable resources and achieving high-speed access through copper twisted pair cables has become the most realistic broadband access network solution with the lowest cost for operators.

DSL technology has been widely used and is a very mature access technology.

The XDSL system is mainly composed of a central office device (DSLAM--Digital Subscriber Line Access Multiplexer) and a client device (CPE), and the central office is composed of a DSLAM access platform, a DSL central office card, a voice splitter, and an IPC (data aggregation device). The voice separator separates the audio signal and the high-frequency digital modulation signal on the line, and sends the audio signal to the first-class switch, and the high-frequency digital modulation signal is sent to the DSL access system; The DSLAM access platform can insert different DSL access cards and NMS cards at the same time. The central office card modulates the signal on the line into a digital signal and provides a data transmission interface; IPC provides different WAN interfaces for DSL access systems, such as ATM, Frame Relay, T1 E1, etc. These devices are located in the exchange room of the ** system.

The user device consists of a DSL modem and a voice splitter, and the DSL modem modulates and demodulates the user's data packets and provides a data transmission interface.

XDSL is a general term for various types of DSL, including ADSL, RADSL, VDSL, SDSL, IDSL, and HDSL. DSL=Digital Subscribe Line=

Digital subscriber lines.

Hello: XDSL1 Foreword With the advent of XDSL technology, copper wires have evolved from low-speed data access that can only transmit voice and 56 kbits, to high-speed data signals. XDSL access technologies based on copper transmission, such as ADSL and HDSL SHDSL, have made copper an important means of broadband user access, and have become the mainstream technology of broadband access, which has been adopted by the majority of users.

According to the latest statistics from the DSL Forum, as of 31 March 2004, the number of XDSL users worldwide had reached 73.4 million. In the XDSL technology system, the most widely used technology in China is the first-generation ADSL technology based on the first twisted pair. However, with the gradual expansion of operators' network coverage and the gradual increase in user traffic, the first-generation ADSL technology has gradually exposed some insurmountable weaknesses, such as:

The low downlink transmission rate is difficult to meet the development of some high-speed services, such as the flow service; With the increasing number of users, how to quickly determine the quality of the line before the opening of the road has become a headache for operators; It is difficult to solve the heat dissipation problem of the device, etc. Due to the needs of business development, in order to better meet the needs of network operation and information consumption, ADSL2, ADSL2+, VDSL and other technologies came into being, which are called the new generation of XDSL technology. The emergence of a new generation of XDSL technology has provided a new impetus for the development of DSL technology to a large extent.

The following content will introduce and discuss the technical characteristics of these technologies and how to deploy applications on carrier networks. The specific introduction is not enough, I will give you the ** and you will take a look.

1. Overview.

The current copper line can reach a rate of 56kbps with the help of software) to carry voice communication, these lines use the existing network, do not require any additional hardware or software, and its advantage is that it can be immediately accessed to any network reachable place, but this is also its disadvantage: the entire network is routed at the rate required in the past.

In an ideal environment, the rate of copper wire is only limited by cable attenuation, but in the existing ** network, the bandwidth is very large, and it is procedurally limited by the filter and the network itself. Upgrading existing copper twisted pair cables can dramatically improve overall network performance, but it can be costly, so you need an approach that can use existing cabling while significantly improving performance. Bellcore invented the first generation of digital user technology and coined the term DSL.

The aim is high performance and low cost: at least 2Mbps of bandwidth on existing copper networks. DSL uses a combination of software and electronics to compensate for some of the shortcomings of copper wires.

XDSL is a general term for DSL (Digital Subscriber Line), which means digital subscriber line, which is a point-to-point transmission technology with copper wire as the transmission medium. DSL technology supports symmetric and asymmetric transmission modes on the user loop of traditional networks (POTS), which solves the problem that often occurs between network service providers and end users"The last mile"transmission bottlenecks. Because the first user loop has been laid in large quantities, how to make full use of the existing copper cable resources, through the copper twisted pair to achieve high-speed access has become the focus of the industry's research, so DSL technology has soon been paid attention to, and in some countries and regions have been widely used.

2. Implementation.

The XDSL system is mainly composed of a central office device (DSLAM--Digital Subscriber Line Access Multiplexer) and a user device (CPE), and the central office is composed of a DSLAM access platform, a DSL central office card, a voice splitter, and an IPC (data aggregation device), among which IPC is an optional device. The voice separator separates the audio signal and the high-frequency digital modulation signal on the line, and sends the audio signal to the first-class switch, and the high-frequency digital modulation signal is sent to the DSL access system; The DSLAM access platform can insert different DSL access cards and NMS cards at the same time. The central office card modulates the signal on the line into a digital signal and provides a data transmission interface; IPC provides different WAN interfaces for DSL access systems, such as ATM, Frame Relay, T1 E1, etc. These devices are located in the exchange room of the ** system.

The user device consists of a DSL modem and a voice splitter, and the DSL modem modulates and demodulates the user's data packets and provides a data transmission interface.