ISO/IEC 9314的这一部分规定了光纤分布式数据接口(FDDI)的单模光纤物理层介质依赖(SMF-PMD)要求，FDDI提供了以光纤波导为传输介质的计算机和外围设备之间的高带宽(100兆位秒)通用互连。FDDI可以被配置为支持大约每秒80兆比特(10兆字节)的持续传输速率。FDDI可能不满足所有无缓冲高速设备的响应时间要求。外国直接投资在分布在数公里范围内的许多站点之间建立了连接。FDDI的默认值是根据1000个物理连接和200公里的总光纤路径长度计算的（参见MAC标准-ISO/IEC 9314-2或ISO/IEC 9314-8)。FDDI包括:1）物理层介质相关（PMD）在四个替代标准中规定:a）ISO/IEC 9314-3（FDDI PMD）对应于多模光纤（MMF），实际上意味着“FDDI MMF-PMD”。b）该标准ISO/IEC 9314-4（SMF-PMD），包含站之间单模光纤（SMF）物理连接的要求。c）ISO/IEC 9314-9（FDDI LCF-PMD），用于更短距离的替代低成本多模光纤（LCF）。d）ISO/IEC 9314-10（FDDI TP-PMD），铜双绞线（TP）替代品。FDDI环可以由所有这些备选方案组成。（一些限制见6.4）。PMD提供从站到站传输适当编码的数字比特流所需的所有服务。SMF-PMD规定了媒体接口连接器（MIC）两侧的FDDI站和电缆设备的互连点要求，以符合使用单-模光纤。SMF-PMD包括以下内容:i)使用单模光纤电缆和光旁路开关的两(2)类有源输出和有源输入接口的光功率预算ii)MIC插座机械配合要求，包括键控功能iii)单模光纤电缆要求iv)PMD向PHY和SMT2提供的服务2)物理层协议(PHY)，提供多模或单模PMD与数据链路层(DLL)之间的连接。PHY与上游码位数据流建立时钟同步，并将该输入码位流解码为等效符号流以供更高层使用。PHY提供数据和控制指示符符号和码位之间的编码和解码、介质调节和初始化、输入和输出码的同步-位时钟，以及向或从更高层传输信息所需的八位字节边界的划定。要在接口介质上传输的信息由PHY编码成分组传输码。3)数据链路层(DLL)，它控制对介质的访问以及帧校验序列的生成和验证，以确保将有效数据正确传送到-8-9314-4？ISO/IEC:1999（E）高层。DLL还涉及设备地址的生成和识别以及FDDI网络内的对等关联。出于PHY的目的，根据媒体访问控制(MAC)实体来引用DLL，它是DLL的最低子层。4)站管理(SMT)，它在站级提供必要的控制，以管理在各个FDDI层中正在进行的过程，使得站可以在环上协同工作。SMT提供诸如控制配置管理、故障隔离和恢复以及调度程序等服务。ISO/IEC 9314的这一部分是ISO/IEC 9314-1的支持文件，应与之一起阅读。有关支持的FDDI工作站和网络配置的信息，请参阅SMT文档ISO/IEC 9314-6。该组FDDI标准规定了确保符合的FDDI实现之间的互操作性所必需的接口、功能和操作。ISO/IEC 9314的这一部分是功能描述。一致的实现可以采用不违反互操作性的任何设计技术。

This part of ISO/IEC 9314 specifies the Single-mode fibre Physical Layer Medium Dependent (SMF-PMD) requirements for the Fibre Distributed Data Interface (FDDI).

FDDI provides a high bandwidth (100 megabits per second) general purpose interconnection among computers and peripheral equipment using a fibre optic waveguide as the transmission medium. The FDDI may be configured to support a sustained transfer rate of approximately
80 megabits (10 megabytes) per second. The FDDI may not meet the response time requirements of all unbuffered high speed devices. The FDDI establishes the connection among many stations distributed over distances of several kilometers in extent. Default values for FDDI were calculated on the basis of 1000 physical connections and a total fibre path length of 200 kilometers (see the MAC Standard – ISO/IEC 9314-2 or ISO/IEC 9314-8).

The FDDI consists of:

1) The Physical Layer Medium Dependent (PMD) is specified in four alternative standards:

a) ISO/IEC 9314-3 (FDDI PMD) corresponding to multimode fibre (MMF) which actually
means "FDDI MMF-PMD".
b) This standard ISO/IEC 9314-4 (SMF-PMD) which contains the requirements for singlemode
fibre (SMF) physical connections between stations.
c) ISO/IEC 9314-9 (FDDI LCF-PMD), an alternative lower cost multimode fibre (LCF) for
shorter distances.
d) ISO/IEC 9314-10 (FDDI TP-PMD), a copper twisted pair (TP) alternative.
An FDDI ring can be made up of all these alternatives. (For some restrictions see 6.4).
The PMD provides all services necessary to transport a suitably coded digital bit stream
from station to station. The SMF-PMD specifies the point of interconnection
requirements for FDDI stations and cable plants at both sides of the Media Interface
Connector (MIC) for conforming stations utilizing single-mode fibre.
SMF-PMD includes the following:
i) The optical power budgets for two (2) categories of Active Output and Active Input
Interfaces using single-mode fibre optic cables and optical bypass switches
ii) The MIC Receptacle mechanical mating requirements including the keying features
iii) The single-mode fibre optic cable requirements
iv) The services provided by PMD to PHY and SMT

2) A Physical Layer Protocol (PHY), which provides connection between multimode or singlemode
PMD and the Data Link Layer (DLL). PHY establishes clock synchronization with the
upstream code-bit data stream and decodes this incoming code-bit stream into an
equivalent symbol stream for use by the higher layers. PHY provides encoding and
decoding between data and control indicator symbols and code-bits, medium conditioning
and initializing, the synchronization of incoming and outgoing code-bit clocks, and the
delineation of octet boundaries as required for the transmission of information to or from
higher layers. Information to be transmitted on the interface medium is encoded by the PHY
into a grouped transmission code.

3) A Data Link Layer (DLL), which controls the accessing of the medium and the generation
and verification of frame check sequences to assure the proper delivery of valid data to the
– 8 – 9314-4？ISO/IEC:1999(E)
higher layers. DLL also concerns itself with the generation and recognition of device
addresses and the peer-to-peer associations within the FDDI network. For purpose of the
PHY, references to DLL are made in terms of the Media Access Control (MAC) entity, which
is the lowest sublayer of DLL.

4) A Station Management (SMT), which provides the control necessary at the station level to manage the processes underway in the various FDDI layers such that a station may work cooperatively on a ring. SMT provides services such as control of configuration management, fault isolation and recovery, and scheduling procedures.

This part of ISO/IEC 9314 is a supporting document to ISO/IEC 9314-1 which should be read in
conjunction with it.

The SMT document ISO/IEC 9314-6 should be consulted for information pertaining to
supported FDDI station and network configurations.

The set of FDDI standards specifies the interfaces, functions and operations necessary to
insure interoperability between conforming FDDI implementations. This part of ISO/IEC 9314 is
a functional description. Conforming implementations may employ any design technique which
does not violate interoperability.