Nec Corporation

Masahiro Eda

Masahiko Fujiwara

A plurality of node apparatuses are connected by an optical transmission line. Each of the node apparatuses is assigned with a wavelength as an address different from the others. Therefore, when a first node apparatus transmits data to a second node apparatus, the data is of a wavelength corresponding to the address of the second node apparatus. The data transmission is carried out in a time slot defined by a frame pulse. The data of the corresponding wavelength is only received in the second node apparatus, and data of other wavelengths are passed through the second node apparatus. Consequently, media-access control is easily carried out independently in each node apparatus in an optical network system by using wavelength division multiplexing.

System for transmitting data using wavelength division multiplexing

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 .lambda.1 through .lambda. n. An access right control packet 10 is transferred in the loop at the optical wavelength of .lambda.1. 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 (.lambda.i) 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 .lambda.i.

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Tokyo, Japan

Masahiro Eda