IEEE 802.3和以太网(3)

IEEE 802.3 架构图解,包括10M,100M,1G,10G。

持10/100/1000Mbps速率。通常情况下，它实现MII/GMII/RGMII接口，来同行业标准PHY器件实现接口。IEEE 802.3标准还规范了以下兼容性接口（Compatibility interfaces）The following important compatibility interfaces are defined within what is architecturally the Physical Layer. 下列重要的兼容性接口被定义在物理层架构里。a) Medium Dependent Interfaces (MDI). To communicate in a compatible manner, all stations shall adhere rigidlyto the exact specification of physical media signals defined in Clause 8 (and beyond) in this standard, and to theprocedures that define correct behavior of a station. The medium-independent aspects of the LLC sublayer andthe MAC sublayer should not be taken as detracting from this point; communication by way of the ISO/IEC8802-3 [IEEE Std 802.3] Local Area Network requires complete compatibility at the Physical Medium interface(that is, the physical cable interface).a）媒体相关接口。为了以兼容的方式通讯，所有站点会严格遵照在本标准字句8（及以后）定义的物理层媒体信号的确切规格，并且严格遵照定义站点正确行为的规程。LLC子层和MAC子层的媒体无关方面不应该被认为从这一点减损；通过ISO/IEC 8802-3 [IEEE Std 802.3]局域网方式通讯需要在物理媒体接口上完全兼容（即，物理电缆接口）。b) Attachment Unit Interface (AUI). It is anticipated that most DTEs will be located some distance from theirconnection to the physical cable. A small amount of circuitry will exist in the Medium Attachment Unit (MAU)directly adjacent to the physical cable, while the majority of the hardware and all of the software will be placedwithin the DTE. The AUI is defined as a second compatibility interface. While conformance with this interface isnot strictly necessary to ensure communication, it is recommended, since it allows maximum flexibility inintermixing MAUs and DTEs. The AUI may be optional or not specified for some implementations of this standardthat are expected to be connected directly to the medium and so do not use a separate MAU or itsinterconnecting AUI cable. The PLS and PMA are then part of a single unit, and no explicit AUI implementation isrequired.连接单元接口（AUI）。也称为附件单元接口。预计大部分的DTE(Data Terminal Equipment，数据终端设备)将被置于离他们到物理电缆连接一段距离。少量的电路将存在于直接毗邻物理电缆的媒体连接单元（MAU，MediumAttachment Unit ），而大部分的硬件和所有的软件都将被放置在DTE中。AUI被定义为第二兼容性接口。虽然为确保通信，和这种接口的一致性不严格必须，但是和这种接口的兼容性是建议的，因为它允许在混杂MAU和DTE的最大的灵活性。AUI可能是可选的或不为本标准的一些实现指定，这些实现预计将直接连接到媒体，所以不使用单独的MAU或它的互联AUI电缆。然后，PLS（Physical Layer Signaling，物理层信令）和PMA（PhysicalMedium Attachment，物理媒体附加）是单个单位的一部分，显式的AUI实现是不必要的。AUI 端口是用来与粗同轴电缆连接的接口，它是一种"D"型15针接口，这在令牌环网或总线型网络中是一种比较常见的端口之一。路由器可通过粗同轴电缆收发器实现与10Base-5网络的连接，但更多的是借助于外接的收发转发器（AUI-to-RJ-45），实现与10Base-T以太网络的连接。当然也可借助于其他类型的收发转发器实现与细同轴电缆（10Base-2）或光缆（10Base-F）的连接。这里所讲的路由器AUI接口主要是用粗同轴电缆作为传输介质的网络进行连接用的，AUI接口示意图如图所示。 AUI:Attachment Unit Interface 连接单元接口c) Media Independent Interface (MII). It is anticipated that some DTEs will be connected to a remote PHY,and/or to different medium dependent PHYs. The MII is defined as a third compatibility interface. Whileconformance with implementation of this interface is not strictly necessary to ensure communication, it isrecommended, since it allows maximum flexibility in intermixing PHYs and DTEs. The MII is optional.媒体独立接口（MII，Meida Independent Interface）。预计一些DTE将被连接到远程的PHY上，并且/或者连接到不同的媒体相关的PHYs。MII被定义为第三兼容接口。 而为确保通信，与此接口实现相一致性不严格必须，和这种接口的兼容性是建议的，因为它允许在混杂PHY和DTE的最大的灵活性。MII是可选的。The Media Independent Interface (MII) is an Ethernet industry standard defined in IEEE 802.3. It consists of adata interface and a management interface between a MAC and a PHY (Fig. 1). The data interface consists of achannel for the transmitter and a separate channel for the receiver. Each channel has its own clock, data, andcontrol signals. The MII data interface requires a total of 16 signals. The management interface is a two-signal

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