ATM interface and shaping method

A shaping method of controlling an interval between cells transmitted to a transmission path in association with a group and a subgroup to which each of the cells belongs, comprising:

• a first step of setting a first peak cell interval corresponding to a peak rate declared for each group in which a one-cell transfer time determined by an output interface rate is used as one unitary time and memorizing a parameter corresponding to a traffic rate declared for each subgroup;
• a second step operative at arrival of a cell of obtaining a relative cell transmission time according to the parameter corresponding to a subgroup to which the cell belongs, the peak cell interval corresponding to the cell being employed as one unitary time;
• a third step of deciding a cell transmission time according to the relative cell transmission time in which a one-cell transfer time determined by the output interface rate is adopted as one unitary time;
• and
• a fourth step of transmitting the cell according to the cell transmission time.

An asynchronous transfer mode (ATM) interface having a shaping function of controlling transmission of ATM cells to an output line according to groups and subgroups to which the cells respectively belong, comprising:

• a buffer memory for temporarily accumulating a plurality of ATM cells supplied via an input line;
• and
• control means for writing the cells in the buffer memory and reading the cells therefrom and transferring the cells to the output line, wherein the control means includes:
• table means for storing therein a first peak cell interval obtained for each group in association with a peak rate declared to the group in which a one-cell transfer time determined according to a cell transmission rate of the output line is used as one unitary time and a control parameter for each subgroup obtained in association with a traffic rate declared for the subgroup in which the first peak cell interval is adopted as one unitary time;
• and
• access means operative when a cell arrives thereat via the input line for obtaining a relative cell transmission time according to the control parameter associated with a subgroup of the cell and stored in the table means in which the first peak cell interval corresponding to the cell being employed as one unitary time, deriving a cell transmission time from the relative cell transmission time in which a one-cell transfer time decided according to an interface rate of the output line is utilized as one unitary time, and reading from the buffer memory each of the cells according to the cell transmission time associated therewith, thereby transmitting the cell to the output line.

An asynchronous transfer mode (ATM) interface having a shaping function of controlling an interval of transmission of ATM cells to an output line, comprising:

• a buffer memory for temporarily accumulating a plurality of ATM cells supplied via an input line;
• and
• control means for writing the cells in the buffer memory and reading the cells therefrom and transferring the cells to the output line, wherein the control means includes:
• first table means for storing therein a control parameter obtained in association with a traffic condition beforehand declared for each group and each subgroup to which the input cells respectively belong;
• second table means for storing therein an available state of each timeslot on the output line;
• and
• the access means for obtaining, when a cell arrives thereat from the input line, transmission timing of the cell according to a control parameter which corresponds to a group and a subgroup of the cell and which is stored in the first table means and referencing the second table means for thereby deciding an available transmission timeslot to be associated with the transmission timing, thereby transferring the cell from the buffer memory to the output line at the timing of the transmission timeslot.