Access method for optical local area network systems

Assignee: NEC Corp

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Filing: 1991-12-27

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Granted: —

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Expires: 2011-12-27

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Abstract

Abstract A supervisory node (2) and non-supervisory nodes (3 through 9) are connected in a loop by an optical transmission path (1). Over the loop (1) are transferred optical signals having wavelengths of λl through λn. An access right control packet 10 is transferred in the loop at the optical wavelength of λl. A node performing data transmission by line exchange writes its own node address (SA), the destination address (DA) and transmit reservation in the header of the access right control packet 10, and sends the packet out on the optical transmission path. The supervisory node 2 having received this access right control packet writes the wavelength to be used (λi) into the used wavelength field (UWL), and notifies the transmit and receive nodes of the choice of the wavelength. The transmit node sends data to the receive node by line exchange at the designated wavelength λi.

Inventors

👤 Masahiro c/o NEC Corporation Eda

Bibliographic Details

Application Number —

Jurisdiction EP

Data Source google_patents

Last Synchronized 2026-11-09 11:50

CPC Classifications

H; H04; H04J; H04J14/00; H04J14/02; H04J14/0227; H04J14/0241; H04J14/0242; H04J14/0245; H04J14/0246; H04L; H04L12/00; H04L12/28; H04L12/42; H04L12/423; H04J14/0201; H04J14/0278; H04J14/0283

Claims Analysis

Total Claims: 2

Claim 1

Independent Claim 324 words

A media access method for use in an optical local area network (LAN) system having a plurality of nodes including a supervisory node and an optical fiber transmission path for data transmission between said nodes, and performing data transmission by a wavelength-division multiplex method using N optical wavelengths, wherein the transmission and reception of data takes place in the following manner: an access right control packet, consisting of a reservation field in which is written transmit reserve information indicating the presence of a data transmission request, a send address field in which is written a send node address, a destination address field in which is written a receive node address and a wavelength designation field in which is written used wavelength information for notifying the nodes of the optical wavelength to be used for data transmission, is transferred by a first optical wavelength between nodes including said supervisory node; when a node is to transmit data, said supervisory node and said receive node are notified of the presence of a data transmission request by writing into said access right control packet said transmit reserve information, the send node's own address, and the address of the receive node to which the data are to be sent and sending the packet; and when said supervisory node, upon perception of said data transmission request from said node, selects one transmit optical wavelength out of the second through Nth optical wavelengths unless said receive node for which the data are to be sent is receiving data, writes the selected wavelength into said access right control packet as said used wavelength information, sends the packet, and thereby notifies said send and receive nodes of said transmit optical wavelength; said send node transmits the data by said transmit optical wavelength or which it has been notified, said receive node takes only said transmit optical wavelength into itself but no other optical wavelengths and instead let them pass as optical signals.

Claim 2

Dependent Claim 153 words

A media access method for use in an optical LAN system, as claimed in Claim 1, wherein: a packet exchanging packet, consisting of an identifier field, a send node address field, a receive node address field and a data section, and another packet exchanging packet, in whose identifier field are written information for distinguishing said access right control packet from said packet exchanging packet, are further transferred at said first optical wavelength; each node receives, out of the packet exchanging packets having flowed into itself, a packet exchanging packet having a receive node address identical with its own node address; and when any node is to transmit packet exchanging data, it sends a packet exchanging packet in said send node address, said receive node address and said data section of which are respectively written the transmitting node's own address, the address of the destination node and the packet exchanging data to be transmitted.

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