Fujitsu Corporation

Nagao Shimada

Tomohiro Shinomiya

Haruo Yamashita

Masatake Miyabe

Masaki Hirota

In a frame relay apparatus or a frame relay method, in order to be able to transfer data between channels having different maximum transfer units, payloads are fragmentized or combined and assembled into a frame, in response to the maximum transfer units of the channels. Fragmentized payloads are associated with the original data. By doing so, especially the number of frames in a channel with a large maximum transfer unit is controlled, and the transfer efficiency of frames of the entire network may be improved.

Method and apparatus for frame relay

A communication device for transmitting and receiving frames, which is capable of preventing an overflow of a buffer memory due to clock error even when the utilization factor of a transmission line is high. A frame holding section stores frames awaiting transmission. A transmission section sequentially takes out each frame from the frame holding section and outputs the frame to the transmission line, based on a control signal indicative of timing for transmitting the frame. A transmission control section initially outputs the control signal at a repetition period of T clocks (T&#x2267;2) and acquires the number of waiting frames in the frame holding section every N&#xd7;T clocks (N&#x2267;2). When the number of waiting frames is equal to K (K&#x2267;1), the transmission control section makes some of transmission intervals shorter than T clocks to thereby output the control signal N+K times during next N&#xd7;T clocks

Communication device and communication method

A communication system that includes a single subscriber line terminal on a network side, a number of terminal units on a user side, and a single transmission line shared thereby multiplexing through polling. In the communication system, a queue length extracting unit extracts from information stored for each connection, a parameter setting unit sets the contracted parameters of a sustainable cell rate and peak cell rate and contracted parameters of fluctuation values, a parameter managing memory stores the queue length information and the contracted parameter information, a bandwidth calculating unit re-stores results of periodic calculation of the cell rates so that the contracted parameters are observed, and a transfer polling information generating unit determines timings of transfer of information in accordance with the calculated allocated cell rates and outputting them.

Network side transmission apparatus and method for controlling variable traffic rate by dynamic bandwidth allocation

A method for time-division multiplexing including steps of generating a plurality of first signals and a plurality of second signals to which specific pulse trains for frame synchronization are allocated respectively; generating low speed signals of plural channels including the first and second signals and transmission signals; a conversion step; and time-division multiplexing the low speed signals after the conversion step, thereby obtaining high speed signals. When applied to SDH, for example, the first and second signals may be A1 bytes and A2 bytes respectively, and the transmission signals may ho payload signals. According to one aspect of the invention, at the conversion step, the first and second signals in each channel are panty convened into either of '1/0' alternating signals and '0/1' alternating signals. Consequently, it becomes possible to reduce the number of successive same code and to diminish the deviation of the mark rate.

Method for time-division multiplexing

There is provided a communication system directed to inhibiting degradation of the efficiency of transmission of user information and improving the communication quality. A correspondence table management unit creates a correspondence table based on table forming information. A buffer status value acquiring unit acquires a buffer status value of a buffer that issues a transmission event. A notice information setting unit compares a size relation between status information about past buffer status values for the buffer and a current buffer status value acquired, and sets notice information on a bit basis. A terminal-side notice information management memory stores and manages the notice information as the status information. A notice information sending unit sends the notice information to notify an upper device of the buffer status. A table forming information sending unit sends the table forming information. A control-side notice information management memory receives and manages the notice information. A buffer status recognizing unit recognizes the buffer status from the content of the control-side notice information management memory.

Communication system preforming control of information between a terminal device and a network side device including buffer management

A subscriber-line-terminating apparatus for dynamically allocating band portions to a plurality of terminal apparatuses includes an in-buffer-information-amount receiving unit for receiving an in-buffer-information amount from each of the terminal apparatuses; an insufficient-band-computing unit for computing an insufficient band portion required by each of the terminal apparatuses; an in-buffer-information-amount-proportional-band-allocating unit for allocating a band portion corresponding to the in-buffer-information amount to each of the terminal apparatuses and a past-use-band-allocating unit for allocating a past-use band part to each of the terminal apparatuses as a past-use band portion based on a first past-use band variable of the terminal apparatus.

Growing community of inventors

Kawasaki, Japan

Nagao Shimada