Nippon Telegraph and Telephone Corporation

Norio Tamaki

Noriki Miki

Kiyomi Kumozaki

Akihiro Otaka

Ryu-ichi Watanabe

Masashi Hashomoto

A packet multiplexing apparatus is presented for multiplexing packets to be transmitted from a number of user facilities to a local service node in such a way to assure equal access to the output port for all the users. The apparatus is provided with input ports for inputting a packet in a respective input port; a buffer memory provided for each input port for temporary storage of a packet; an output signal transmission circuit for retrieving a packet from each buffer memory in a specific sequence; an output port for transmitting packets output from the output signal transmission circuit; and a retrieval sequencing section for controlling the specific sequence by changing a retrieving order of packets from buffer memories for each complete round of packet retrieval so that a frequency of the retrieving order for each input port is uniformly shared by the input ports.

Packet multiplexing apparatus

An optical WDM transmission system formed by integrating by using an optical WDM device at least two point-to-multipoint optical transmission systems which provide independent services by using optical signals of different wavelengths. It provides a plurality of user terminals with optical signals obtained by splitting with an optical splitter an optical signal which is wavelength multiplexed by the WDM device. The splitting numbers of optical splitters placed ahead of or behind the WDM device are set such that a loss from the center terminal to the user terminals of each optical transmission system falls within an allowed loss of each system. Since the splitting numbers of the optical system of each system can be set independently, each system can accommodate a maximum number of user terminals per center terminal within the allowed loss of the system.

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Tokyo, Japan

Norio Tamaki