Browse Prior Art Database

Hot Pluggable Modular Optical Multistation Access Unit

IP.com Disclosure Number: IPCOM000121326D
Original Publication Date: 1991-Aug-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 2 page(s) / 122K

Publishing Venue

IBM

Related People

Gfeller, F: AUTHOR [+4]

Abstract

This article proposes a modularly designed Optical Concentrator, to which multiple stations are attached without the need for electo- optical conversion for each station, allowing controlling of station insertion processes by optical low-speed signalling independent of the data transmission speed. The modular design of the concentrator allows for hot pluggability.

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This is the abbreviated version, containing approximately 52% of the total text.

Hot Pluggable Modular Optical Multistation Access Unit

      This article proposes a modularly designed Optical
Concentrator, to which multiple stations are attached without the
need for electo- optical conversion for each station, allowing
controlling of station insertion processes by optical low-speed
signalling independent of the data transmission speed.  The modular
design of the concentrator allows for hot pluggability.

      Proposed is a concentrator consisting of three types of modules
as shown in the figure:

      The Control Module 1 has the full functionality of a station
and contains control and powering functions for the other modules.
It is the only part of the concentrator containing electro-optical
converters working at the data rate.  Therefore, it is the only
module of the concentrator that has to be changed in case of a change
of the high-speed data signals (e.g., an upgrade from 100 Mb/s to 1
Gb/s). The Concentrator Control block 2 controls and powers attach
modules 3, switches 4, and the optical amplifier 5 via an electrical
bus 6.  Each station can be separately controlled and (optically)
switched off (decoupled) from the network via the Control Module's
management function. Stations can notify the Concentrator Control
unit via the low-speed signalling about the intention of inserting
without needing to understand the (optical) high-speed data signal
protocols, allowing the Control Module's management function to take
actions required for graceful insertion of stations, e.g., by holding
off a token.

      There is one Attach Module for each station.  It contains a
simple (low speed) optical receiver 7 that monitors the station's
sending fiber 8 by tapping a small amount of power, e.g., -10 dB.  It
decodes low-speed signals from the station that are sent before a
station wants to insert itself into the network.  Furthermore, the
receiver monitors the average power of the high-speed signal when a
station is inserted in order to detect cable breaks or unplanned
shutdowns of a station.  The attach modules are plugged into a group
module 9.

      A concentrator may house one or more Group Modules 9. Each
Group Module contains an optical amplifier 5 and as many optical
switches 4...