Abstract: Traditional interception is hard to be implemented in Asymmetric Digital Subscriber Line（ADSL） because of its end-to-end architecture.Analyzing the encapsulating methods ADSL carrying network traffic and user authentication，the gateway based on Digital Subscribe Loop Access Multiplexer（DSLAM） technology is designed.This paper describes the picking-up of IP packages and the mapping of ATM channels in detail and the user’s network traffic is online intercepted.

Key words: Asymmetric Digital Subscriber Line（ADSL）, Digital Subscribe Loop Access Multiplexer（DSLAM）, Asynchronous Transfer Mode（ATM）, interception

摘要： 由于ADSL（Asymmetric Digital Subscriber Line）端到端的通讯结构，传统的监听技术很难进行，在分析了ADSL数据承载方式和用户认证的基础上，设计了一种基于DSLAM（Digital Subscribe Loop Access Multiplexer）技术模式的监听网关。详细描述了IP数据的获取以及ATM通道的映射，实现了对ADSL用户网络层数据的在线监听。

关键词: 非对称数字用户线路（ADSL）, 数字用户线接入复用器（DSLAM）, 异步传输模式（ATM）, 监听