本标准规定了使用IEEE 802 LAN技术将网桥及其管理扩展到物理机柜之外所需的设备、协议、程序和受管对象。为此，它:a）识别并隔离扩展网桥内端口之间的流量；b） 指定此标识的标签格式；c） 建立由控制网桥和一个或多个网桥端口扩展器组成的扩展网桥；d） 指定网桥端口扩展器的功能和特定要求；e） 跨互连的网桥端口扩展器扩展网桥端口的MAC服务，包括支持客户虚拟局域网（C-VLAN）。f） 确定连接桥接端口扩展器的桥接组件和系统的要求；g） 指定一个协议，用于通过控制网桥配置和监控网桥端口扩展器； 和h）制定桥梁管理的要求，以支持港口扩展、识别管理对象并定义管理操作。

This standard specifies the devices, protocols, procedures, and managed objects necessary to extend a bridge and its management beyond its physical enclosure using IEEE 802 LAN technologies. To this end, it: a) Identifies and isolates traffic between ports within an Extended Bridge; b) Specifies a tag format for this identification; c) Establishes an Extended Bridge consisting of a Controlling Bridge and one or more Bridge Port Extenders; d) Specifies the functionality and the specific requirements of a Bridge Port Extender; e) Extends the MAC service of a Bridge Port across the interconnected Bridge Port Extenders, including support of Customer Virtual Local Area Networks (C-VLANs). f) Establishes the requirements of bridge components and systems for the attachment of Bridge Port Extenders; g) Specifies a protocol to provide for the configuration and monitoring of Bridge Port Extenders by a Controlling Bridge; and h) Establishes the requirements for Bridge Management to support Port Extension, identifying the managed objects and defining the management operations.