Information Processing Systems - Fibre Distributed Data Interface (FDDI) - Part 3: Physical Layer Medium Dependent (PMD)
|Publication Date:||15 October 1990|
|ICS Code (Interface and interconnection equipment):||35.200|
This part of ISO/IEC 9314 specifies Physical Layer, Medium Dependent (PMD) requirements for the Fibre Distributed Data Interface (FDDI).
The FDDI provides a high-bandwidth (100 Mbit/s) general-purpose interconnection among computers and peripheral equipment using fibre optics as the transmission medium. The FDDI may be configured to support a sustained transfer rate of approximately 80 Mbit/s (10 Mbyte/s). It may not meet the response time requirements of all unbuffered high-speed devices. The FDDI establishes the connection among many FDDI nodes (stations) distributed over distances of several kilometres in extent. Default values for FDDI were calculated on the basis of 1 000 physical connections and a total fibre path length of 200 km.
The FDDI consists of
(a) A Physical Layer (PL) which is divided into two sublayers:
(1) A Physical Layer, Medium Dependent (PMD), which provides the digital baseband point-to-point communication between nodes in the FDDI network. PMD shall provide all services necessary to transport a suitably coded digital bit stream from node to node. PMD specifies the point of interconnection requirements for conforming FDDI stations and cable plants at both sides of the Media Interface Connector (MIC). PMD includes the following:
-The optical power budgets for cable plants using 62,5/125 μm fibre optic cables and optical bypass switches.
-The MIC receptacle mechanical mating requirements including the keying features.
-The 62,5/125 μm fibre optic cable requirements.
-The services provided by PMD to PHY and SMT.
(2) A Physical Layer Protocol (PHY), which provides connection between 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.
(b) A Data Link Layer (DLL), which controls the accessing of the medium and the generation and verification of frame check sequences to ensure the proper delivery of valid data to the other layers. DLL also concerns itself with the generation and recognition of device addresses and the peer-to-peer associations within the FDDI network. For the purposes of this part of ISO/IEC 9314, references to DLL are made in terms of the Media Access Control (MAC) entity, which is the lowest sublayer of DLL.
(c) A Station Management (SMT)1) which provides the control necessary at the node level to manage the processes underway in the various FDDI layers such that a node may work co-operatively 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 should be consulted for information pertaining to supported FDDI node and network configurations.
ISO/IEC 9314 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.
1) SMT will form the subject of a future part of ISO/IEC 9314.