Overview
ISO/IEC 9314-3:1990 - Information processing systems - Fibre Distributed Data Interface (FDDI) - Part 3: Physical Layer Medium Dependent (PMD) defines the medium-dependent aspects of the FDDI physical layer. It describes the optical point‑to‑point baseband transmission used in a 100 Mbit/s token‑ring architecture over fibre optics, specifying the interconnection point (Media Interface Connector - MIC), cable‑plant requirements, optical power budgets, and the services PMD provides to the PHY and station management (SMT). Annexes A–G supply test methods, optical procedures, cable options, electrical considerations, jitter allocation, keying guidance and reference test plugs.
Key topics and technical requirements
- Scope & performance: Supports FDDI high‑bandwidth interconnection at 100 Mbit/s (sustained ~80 Mbit/s), designed for multi‑station networks with total path lengths up to several kilometres (default calculations based on 1 000 physical connections and 200 km total fibre).
- Fibre and cable plant: Specifies 62.5/125 µm fibre optic cable requirements, suggested fibre types, bandwidth and attenuation values, connectors and splice considerations, and bypass switch behavior.
- Media Interface Connector (MIC): Mechanical mating, receptacle/plug geometry and keying details to ensure intermateability and correct optical reference plane.
- Optical interfaces: Defines active output/input characteristics, optical rise/fall times, pulse envelopes, transmitter/receiver requirements, centre wavelength and spectral width.
- Station bypass & timing: Bypass interface behavior, timing characteristics and the need to maintain cable continuity when a station is isolated.
- Signal detect and jitter: Signal detect thresholds, timing and definitions of jitter types relevant to FDDI PMD - data‑dependent jitter (DDJ), duty cycle distortion (DCD) and random jitter (RJ) - plus test patterns and measurement methods.
- PMD services: Services to PHY (clock sync, code‑bit transport, encoding/decoding boundary) and SMT (management interfaces and status).
Applications and who uses it
- Network equipment manufacturers designing FDDI transceivers, MIC receptacles, concentrators and bypass switches.
- Cable and systems integrators specifying fibre plant, loss budgets and connectorization for FDDI rings.
- Test laboratories and QA engineers implementing the standard’s test methods (Annex A/B) and jitter/allocation procedures (Annex E).
- Network architects and legacy system maintainers working with token‑ring fibre backbones or documenting historical deployments.
- Standards bodies and engineers needing interoperability and compatibility guidance for FDDI physical implementations.
Related standards
- ISO/IEC 9314-1: Token Ring Physical Layer Protocol (PHY) - complements PMD for encoding/decoding and clocking.
- ISO/IEC 9314-2: Token Ring Media Access Control (MAC) - defines data link layer behavior.
- Consult SMT documents (Station Management) for node and configuration management details.
Keywords: ISO/IEC 9314-3:1990, FDDI PMD, Physical Layer Medium Dependent, 100 Mbit/s token ring, MIC, 62.5/125 µm fibre, optical power budget, jitter, station bypass.