Multimedia jitter removal in an asynchronous digital home network

A method and an apparatus using a system level clocking scheme to remove jitter from multi-media packets distributed over an asynchronous network, in particular an Ethernet network. The present invention overcomes the problems associated with jitter introduced in an Ethernet network by using various time stamps to synchronize a client device clock to a headend clock and to control the data flow in the client device to match the rate that the data is received by a broadband receiver coupled to the headend. A first time stamp is prepended to the transport packets when the packets are received from the headend. A second time stamp is placed in the data frame when the data frame is placed on the network. A third time stamp is placed in the data frame when the data frame is received from the network. The second and third time stamps are used for clock synchronization and the first time stamp is used for data flow control. According to the present invention, the time stamps are added at the physical layer so that the time stamps correspond to the actual time the data packets are placed onto and received from the asynchronous network. 一种方法和装置，利用系统级定时方案从在特别是以太网的异步网络上分发的多媒体报文分组中消除抖动。本发明通过利用各种时间戳将客户端设备时钟同步到头端器时钟上，和控制客户端设备中的数据流以和由连接至头端器的宽带接收机接收数据的速率相匹配，克服了与在以太网中引入的抖动相关的问题。当从头端器接收到报文分组时，第一时间戳被预先挂起到传输报文分组。当数据帧被放置在网络上时，第二时间戳被放置在该数据帧中。当从网络接收到数据帧时，第三时间戳被放置在该数据帧中。第二和第三时间戳被用于时钟同步，第一时间戳被用于数据流控制。根据本发明，时间戳被添加在物理层处，以致时间戳与数据报文分组被放置在异步网络上和从异步网络接收数据报文分组的实际时间相对应。