Browse Prior Art Database

Method for Interconnecting Present And Future Optical Networks Via Switches

IP.com Disclosure Number: IPCOM000100729D
Original Publication Date: 1990-May-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 95K

Publishing Venue

IBM

Related People

Cheng, T: AUTHOR [+3]

Abstract

Disclosed is a method for interconnecting fiber-optic computer networks via switches. Computer networks are conventionally interconnected via gateways or bridges which provide the functions of routing, protocol conversion, flow control, and buffering. The disclosed method allows many fiber-optic networks to be interconnected through electronic or optical switches of lesser complexity. This is achieved by the use of multiple optical wavelengths for communication. Two different implementations of the method are described below, one using an all-optical switch and the second an electronic switch. (Image Omitted)

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

Method for Interconnecting Present And Future Optical Networks Via Switches

       Disclosed is a method for interconnecting fiber-optic
computer networks via switches.  Computer networks are conventionally
interconnected via gateways or bridges which provide the functions of
routing, protocol conversion, flow control, and buffering.  The
disclosed method allows many fiber-optic networks to be
interconnected through electronic or optical switches of lesser
complexity.  This is achieved by the use of multiple optical
wavelengths for communication.  Two different implementations of the
method are described below, one using an all-optical switch and the
second an electronic switch.

                            (Image Omitted)

      The method of implementation with all-optical switches is
illustrated in the figure, which shows four passive optical star
networks interconnected through a switch.  Two distinct optical
wavelengths are used in the system, g1 and g2 .  All intra-network
communication in each passive-star network is performed at wavelenght
g1 using a medium-access protocol, such as Carrier-Sense
Multiple-Access (CSMA) or Token Bus.  Each network may use a
different medium-access protocol.  A second wavelength g2 is used
solely for communicating control messages between the switch and the
network nodes.  The switch-ports respond to the control messages at
wavelength g2 while allowing all messages at wavelength g1 to pass
through transparently.

      The inter-network communication is performed as follows:  If a
node 1 in one of the networks P needs to communicate with a node 2
in a different network Q, it first sends a connect-request to the
switch using wavelength g2 .  The switch, on recognizing this
request, sets up a connection between the two networks. When the
connection is made, the networks P and Q are physically joined, and
node 1 can start to communicate with node 2 on wavelength g1 using
the medium-access protocol employed in network Q.  This medium-access
protocol may or may not be the same as that employed in network P.
Messages between nodes 1 and 2 transmitted at wavelength g1 pass
through the switch unimpeded.  While the message-transmission is in
progress, the wavelength of g2 can b...