Kabushiki Kaisha Toshiba

Nippon Telegraph and Telephone Corporation

Tomoo Kunikyo

Osamu Yamagishi

Keiichi Obara

Kazuo Nogami

Tamiya Ochiai

Shigeaki Tanimoto

Hirobumi Karasawa

Tatsuo Kaji

Tadashi Kayano

An information communication system in which a switch constituting section (,) housing a data generating source is connected to a center switch constituting section (,) through a communication channel (,) using an ATM technology as if the function of an ATM switch of distributed arrangement type was realized. This information communication system flexibly handles new kinds of information provided with the progress of times, and, even when a fault occurs, properly copes with the fault.

Communication system

An improved time slot allocation method for a loop network. Loop networks in which the present invention is applied include a loop-connecting a control station and a number of branch stations. The control and branch stations each have at least one terminal connected thereto such that interstation communication, when demanded by a terminal, is made by passing a frame through the transmission path. The frame includes a synchronization area for indicating the leading end of the frame, a fixed-length control area, and a data area composed of a plurality of time slots. According to the invention, the control and branch stations are each allocated with a predetermined or unique number of time slots to be used by terminals for interstation communication. When a station has its reserve of unused time slots fall below a preset lower limit, the control station supplements time slots from its own reserve. On the other hand, if a station has its reserve exceed a preset upper limit, the station returns the excess time slots to the control station. Thus, wait times for a communication demand before a line connection is established are reduced, with enhanced control station response. Also, efficiency of time slot use is enhanced, with a considerable reduction in call losses.

Time slot allocation for loop networks

The present invention relates to a loop network arranged by loop-connecting a control station and a number of substations through a main transmission path where at least one of the substations comprises a branch station inserting and coupling another station into the main transmission path as a lobe or subloop. In order to prevent an out-of-step condition of the main transmission path, resulting from a failure in the lobe or subloop, the branch station includes a frame buffer for normally selecting the signal from the lobe or subloop and selecting the signal from the main transmission path during detection of a failure and on a bypass command, and for accumulating the selected signal in units of a single frame, and a mechanism for supplying the accumulated signal to the main transmission path.

Loop network

Growing community of inventors

Tokyo, Japan

Tomoo Kunikyo