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Browse Prior Art Database

Method for Distributed Allocation of Circuit-Switched Channels in a Multichannel Optical Network

IP.com Disclosure Number: IPCOM000119992D
Original Publication Date: 1991-Mar-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 4 page(s) / 176K

Publishing Venue

IBM

Related People

Varma, A: AUTHOR

Abstract

Disclosed is a method for distributed assignment of circuit-switched channels in a multichannel optical network. In a multichannel optical network, the aggregate bandwidth of an optical medium is divided among multiple communication channels. Two well-known methods of implementing such networks are wavelength-division multiplexing (WDM) and optical subcarrier multiplexing. In the case of WDM, each individual channel corresponds to a distinct optical wavelength [1]. In the case of subcarrier multiplexing, the channels are created by the use of individual subcarrier signals, similar to the carriers in broadcast television [2]. In either case, each station in such a system is equipped with an agile transmitter and a tunable receiver which can be operated in parallel.

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This is the abbreviated version, containing approximately 34% of the total text.

Method for Distributed Allocation of Circuit-Switched Channels in
a Multichannel Optical Network

      Disclosed is a method for distributed assignment of
circuit-switched channels in a multichannel optical network. In a
multichannel optical network, the aggregate bandwidth of an optical
medium is divided among multiple communication channels.  Two
well-known methods of implementing such networks are
wavelength-division multiplexing (WDM) and optical subcarrier
multiplexing.  In the case of WDM, each individual channel
corresponds to a distinct optical wavelength [1].  In the case of
subcarrier multiplexing, the channels are created by the use of
individual subcarrier signals, similar to the carriers in broadcast
television [2].  In either case, each station in such a system is
equipped with an agile transmitter and a tunable receiver which can
be operated in parallel.  The tuning is performed in the optical
domain in the case of WDM, and in the electronic domain in the case
of optical subcarrier multiplexing.  We assume that the transmitter
and receiver of a station can be tuned independently to distinct
channels.  Each receiver is capable of receiving data only from the
channel it is tuned to.

      We assume that the system contains N stations and b channels.
When multiple channels are available for communication, the channels
should be assigned among the communication-requests such that no
conflicts result.  In the networks considered, re-configuration of
communication paths is assumed to be infrequent enough to allow the
use of circuit-switched operation of the network.  The assignment of
channels to communication-requests can be achieved either by the use
of a centralized controller or by a distributed control algorithm.
The disclosed method avoids the use of a centralized control point.
This results in a robust method as well as improved speed because of
the parallelism in the assignment algorithm.

      The mode of communication assumed is the general multicast,
where the connection requests consist of a set of multicast
connections.  That is, station i needs to connect to ni (0 & ni &
N-1) other stations such that no two source stations will be
connected to the same destination station. Note that one or more of
the connections can be pairwise connections.  We assume the number of
channels b is a number between 1 and N.

      The distributed control algorithm is stored in each station so
that the steps in the algorithm can be executed synchronously by all
stations; asynchronous operation can be allowed by inserting
synchronization steps in the algorithms.  Each step in the algorithms
is performed by all stations unless indicated otherwise.  Whenever
communica tion has to take place between two stations in any step of
these algorithms, they do so using the channel indicated. Station i
is assumed to have the following registers:
 ID(i)  Stores the address of the station.  ID[i] equals i before the
ini...