Network system transmission control method

• US 6,088,363 A
• Filed: 12/04/1997
• Issued: 07/11/2000
• Est. Priority Date: 12/04/1996
• Status: Expired due to Term

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Shiobara, Yasuhisa
• Primary Examiner(s): Kizou, Hassan
• Assistant Examiner(s): Elallam, Ahmed
• Application Number:
  US08/984,952
• Time in Patent Office: 950 Days
• Field of Search: 370/389, 370/400, 370/407, 370/425, 370/442, 370/461, 370/462, 370/471, 709/213, 709/225
• US Class Current: 370/461
• CPC Class Codes: H04L 47/50 Queue scheduling

Abstract

To improve the method of scheduling data transfer requests based on the transfer completion times to the transfer addresses which are assigned to the data for which transfers are requested. A limit time is assigned as an attribute to the data for which transfer is requested from control system 1. The transmission station which becomes the data station (transmission control processing circuit 12) produces a transfer completion time, taking the limit time as the upper digit, the count value of counter 13 which counts a constant clock as the middle digit and the number inherent to the transmission station as the lower digit, and transfers to the transmission station, which becomes the master station, output request control information which includes the data packet length found from this transfer completion time and the data length to be transferred. The transmission station, which becomes the master station, (transmission control processing circuit 12 and reception control processing circuit 17) determines the order given to output permissions based on the transfer completion times, determines the number of output requests permitted based on the data packet lengths, and schedules output permissions for the output requests of multiple transmission stations.

Claims

1. A network system transmission control method comprising the steps of:

assigning a limit time as an attribute for data for which transfer is requested;

generating, by a first data station, a transfer completion time by combining the limit time as a first value, a count value of a counter which measures a specified clock as a second value, and an inherent number of the data station as a third value;

transferring, by the first data station, first output request control information including the transfer completion time and a data packet length obtained from a data length to a master station;

determining, by the master station, an order for a plurality of output permissions for a plurality of output requests of a plurality of transmission stations based on the transfer completion time;

determining, by the master station, a number of the plurality of output requests to which the plurality of output permissions is given based on the data packet length; and

scheduling, by the master station, the plurality of output permissions.

2. The method according to claim 1, wherein:

the step of assigning further comprises assigning a transfer data priority discriminator as an attribute for the data for which transfer is requested indicating whether the data comprises one of transfer time guaranteed data and transfer optimum data, the method further comprising the step of

generating, by a second data station, the first output request control information including the transfer data priority discriminator,

the step of transferring further comprises transferring the first output request control information to the master station every specified time interval which comprises slot and; and

the step of scheduling further comprises scheduling the plurality of output permissions for a group of the plurality of output requests which include transfer time guaranteed data and transfer optimum data every slot time.

3. The method according to claim 2, further comprising the steps of:

determining, by the master station, a marshalling order of received first output request control information based on the transfer completion time;

monitoring, by the master station, remaining time allocated to the output of transfer time guaranteed data in one of the specified time intervals as an asynchronous period; and

reading, by the master station, the transfer completion time and the data packet length of transfer optimum data from the first output request control information in the case of the output of transfer optimum data within the asynchronous period being judged to be possible.

4. The method according to claim 2, further comprising the steps of:

determining, by a second data station, an order of the first output request control information based on the transfer completion time;

transferring, by the second data station, only the first output request control information of the transfer time guaranteed data to the master station;

monitoring, by the master station, remaining time allocated to the output of transfer time guaranteed data within a specified time interval as an asynchronous period;

determining, by the mast station, a first maximum data length for the output of transfer optimum data within the asynchronous time;

outputting, by the master station, transfer optimum output permission information which includes the first maximum data length;

sequentially reading, by a third data station which receives the transfer optimum output permission information, the data packet length from the first output request control information of the transfer optimum data; and

outputting transfer optimum data in a range of the first maximum data length or less.

5. The method according to claim 4, further comprising the steps of:

reading, by the master station, a second maximum data length for a transfer addressee data station number from predetermined lists including each transmission station if it is determined that the output of transfer optimum data is possible during the asynchronous time;

outputting, by the master station, transfer optimum data output permission information which includes the second maximum data length when the second maximum data length is less than the first maximum data length;

outputting, by a fourth data station which receives the transfer optimum output permission information, transfer optimum data in a range of the second maximum data length or less; and

limiting the data length of the transfer optimum data outputted to every transfer addressee transmission station.

6. The method according to claim 1, further comprising the steps of:

assigning a transfer data priority discriminator as an attribute for data for which transfer is requested, wherein the data priority discriminator indicates whether the data is one of transfer time guaranteed data and transfer optimum data;

generating, by a second data station, the first output request control information including the transfer data priority discriminator;

seeking a slot waiting number and a slot limit number based on the limit time in the case of transfer time guaranteed data;

determining an order in which to arrange the first output request control information based on the slot waiting number and slot limit number;

sequentially transferring to the master station the first output request control information every specified time interval including slot time;

determining, by the master station, an order in which output permission is given based on the limit time; and

scheduling every slot time.

7. The method according to claim 6, wherein, in the case of transfer optimum data,

a third data station transfers the transfer request control information to the master station;

the master station determines a line-up order of the received first output request control information based on the transfer completion time, monitors remaining time allocated to the output of transfer time guaranteed data within a said specified time interval as an asynchronous period, and reads the transfer completion times and the data packet lengths of the transfer optimum data from the first output request control information in the case of the output of transfer optimum data being judged possible within the asynchronous period.

8. The method according to claim 6, wherein, in the case of transfer optimum data,

a third data station determines a line-up order of the first output request control information based on the limit time but does not execute output of the first output request control information;

the master station monitors the remaining time allocated to output of transfer time guaranteed data within a specified time interval as an asynchronous period, determines a first output maximum data length for which output of transfer optimum data is possible within the asynchronous period, and transfers the transfer optimum data output permission information which includes the first maximum data length to data stations; and

a fourth data station which receives the transfer optimum data output permission information sequentially reads the data packet length from the first output request control information of the transfer optimum data and outputs transfer optimum data in a range of the first output maximum data length or less.

9. The method according to claim 8, further comprising the steps of:

reading, by the master station, a second output maximum data length for the transfer addressee data station number from predetermined lists including every transmission station in the case of the output of transfer optimum data being judged possible within the asynchronous period;

outputting transfer optimum data output permission information including the second output maximum data length when the second output maximum data length is in a range of the first output maximum data length or less;

outputting, by a fifth data station which receives the transfer optimum data output permission information, transfer optimum data in a range of less than the second output maximum data length; and

limiting the data length of the transfer optimum data which is outputted to every transfer addressee transmission station.

10. The method according to claim 1, wherein:

the step of assigning further comprises assigning a transfer data priority discriminator as an attribute of data for which transfer has been requested indicating whether the data comprises one of transfer time guaranteed data and transfer optimum data, and, when the data comprises transfer time guaranteed data, the method further comprises

determining, by a second data station, a slot waiting number and a slot limit number based on the limit time;

generating, by the second data station, second output request control information which includes the transfer data priority discriminator, the slot waiting number and the slot limit number and the data packet corresponding to the data which is to be transferred;

transferring, by the second data station, the second output request control information to the master station in an order which is determined based on the slot waiting number and slot limit number every specified time interval including a slot time;

determining, by the master station, a number of output requests to which output permission is given based on the data packet length using the slot waiting number and the slot limit number instead of the transfer completion time; and

scheduling every slot time.

11. The method according to claim 10, wherein, in the case of transfer optimum data,

a third data station transfers the transfer request control information to the master station, and

the master station determines a line-up order of the received output request control information based on the transfer completion time, monitors the remaining time allocated to the output of transfer time guaranteed data within a specified time interval as an asynchronous period, and reads the sequential transfer completion time and the data packet length form the output request control information in the case of the output of transfer optimum data being judged possible within the asynchronous period.

12. The method according to claim 10, wherein, in the case of transfer optimum data,

a third data station determines a line-up order of the first and second output request control information based on the limit time, but does not execute output of the first and second output request control information;

and

the master station monitors the time remaining allocated to the output of transfer time guaranteed data within a specified time interval as an asynchronous period, determines a first output maximum data length for which transfer optimum data output is possible within the asynchronous period, and transfers transfer optimum data output permission information including the first output maximum data length at at least one data station; and

a fourth data station which receives the transfer optimum data output permission information sequentially reads the data packet length from the output request control information of the transfer optimum data and outputs transfer optimum data in a range of the first output maximum data length or less.

13. The method according to claim 12, wherein, in the case of transfer optimum data,

a fifth data station reads a second output maximum data length for the transfer addressee data station number from predetermined lists including every transmission station in the case of the output of transfer optimum data being judged possible within the asynchronous period and outputs transfer optimum data output permission information which includes the second output maximum data length when the second output maximum data length is in a range of the first output maximum data length or less;

and

a sixth data station which receives the transfer optimum data output permission information outputs transfer optimum data in a range of the second output maximum data length or less and limits the data length of the transfer optimum data which the sixth data station outputs to every transfer addressee transmission station.

14. The method according to claim 1, wherein:

the step of assigning further comprises assigning a transfer data priority discriminator as an attribute to the data for which transfer is requested indicating whether the data comprises one of transfer time guaranteed data and transfer optimum data and, in the case of transfer time guaranteed data, the method further comprises

determining, by a second data station, a slot waiting number and a slot limit number based on the limit time;

generating, by the second data station, second output request control information which includes a data packet length corresponding to the slot waiting number, the slot limit number and the data length to be transferred; and

transferring, by the second data station, the second output request control information to the master station in an order determined based on the slot waiting number and the slot limit number every specified time interval including slot time; and

the master station determines the order of granting output permission based on the slot waiting number and slot limit number, determines the number of output requests to which output permission is given based on the data packet length and a predetermined extended output maximum data length, and permits output in excess of the slot time frame in the case of an accumulation of output requests for urgent transfer time guaranteed data.

15. The method according to claim 14, wherein, in the case of transfer optimum data,

a third data station transfers the transfer request control information to the master station in the order determined based on the transfer completion times;

and

the master station determines a line-up order of the received output request control information based on the transfer completion times, monitors the remaining time allocated to the output of transfer time guaranteed data within a specified time interval as an asynchronous period, and reads the transfer completion time and the data packet length of the transfer optimum data from the output request control information in the case of output of transfer optimum data being judged possible within the asynchronous period.

16. The method according to claim 14, wherein, in the case of transfer optimum data,

a third data station determines a line-up order of output request control information based on the limit time, but does not output the output request control information;

and

the master station monitors the remaining time allocated to the output of transfer time guaranteed data within a specified time interval as an asynchronous period, determines a first output maximum data length for which transfer optimum data output is possible within the asynchronous period, and transfers transfer optimum data output permission information which includes the first output maximum data length to the data stations, and

a fourth data station which receives the transfer optimum data output permission information, sequentially, reads the data packet length from the transfer optimum data output request control information and outputs transfer optimum data in a range of the first output maximum data length or less.

17. The method according to claim 16, wherein, in the case of transfer optimum data,

a fifth data station reads a second output maximum data length for the transfer addressee data station number from predetermined lists including every transmission station in the case of the output of transfer optimum data being judged possible within the asynchronous period, and outputs transfer optimum data output permission information which includes the second output maximum data length when the second output maximum data length is in the range of the first output maximum data length or less, and

a sixth data station which receives the transfer optimum data output permission information outputs transfer optimum data in a range of the second output maximum data length or less, and limits the data length of the transfer optimum data which the sixth data station outputs to every transfer addressee transmission station.

19. In the network system transmission control method according to claim 18, a network system transmission control method which adopts the network system transmission control method stated in any of claims 2, 6, 10 or 14, wherein the step of enabling further comprises:

enabling judgement of whether or not a data packet of transfer time guaranteed data which an output addressee data station has outputted has been received by the transfer addressee data station.

20. The method according to any of claims 4, 5, 8, 9, 12, 13, 16, or 17, further comprising:

providing, by the master station, within the specified time, a synchronous period to cause the execution of the output of transfer time guaranteed data, a reception period in which output requests for transfer time guaranteed data are received, and an asynchronous period comprising the remaining time after the synchronous period and the reception period are subtracted from the specified time;

causing, by the master station, the output of transfer time guaranteed data from the data station in the specified time by outputting output permission information for the transfer time guaranteed data based on the output request control information received up to that point;

causing, by the master station, the output of output request control information from a transmitting data station in the reception period by outputting enquiry packets which urge output requests for transfer time guaranteed data;

causing, by the master station, the output of output request control information from each data station by outputting enquiry packets which urge output requests for transfer optimum data sequentially to each data station in a predetermined output request search list, in the case of the output of transfer optimum data being judged possible within the asynchronous period

causing, by the master station, the output of transfer optimum data from each data station by outputting output permission information for transfer optimum data; and

scheduling, by the master station, output permission to output requests for transfer time guaranteed data and transfer optimum data every slot time for multiple transmission stations using a bus type network.

21. The method according to any of claims 4, 5, 8, 9, 12, 13, 16, or 17, wherein

the master station and a plurality of data stations are connected by full duplex communication star-type transmission paths and

the master station has, within the specified time, a synchronous period in which the master station causes the execution of the output of transfer time guaranteed data, an asynchronous period comprising the remaining time when the synchronous period is subtracted from the specified period, and a reception period in which the master station receives output requests for transfer time guaranteed data and transfer optimum data by operating the synchronous period and the asynchronous period in parallel, the method further comprising

causing, by the master station, the output of transfer time guaranteed data from data stations by outputting output permission information for transfer time guaranteed data in the synchronous period;

causing, by the master station, the output of transfer optimum data from data stations by outputting output permission information for transfer optimum data in the case of the output of transfer optimum data being judged possible in the asynchronous period and

scheduling, by the mast station, output permissions for the transfer time guaranteed data and transfer optimum data output requests of multiple transmission stations, every slot time, using the star-type network.

22. The method according to any of claims 6, 10 or 14, further comprising:

computing, by a third data station, float time (Taf) by subtracting current time and the transfer minimum time (Trq), which is predetermined for every transfer addressee data station, from the limit time;

computing, by the third data station, a slot limit number (Nm) by dividing the s float time (Taf) by the slot time (Ts);

computing, by the third data station, a trial possible number (Ntr) by dividing the float time (Taf) by the transfer minimum time (Trq);

computing, by the third data station, a trial subtrahend (Nr) based on a function (f(Ntr, STNo, K (constant))) predetermined for every transfer addressee data station (STNo); and

computing, by the third data station, a slot waiting number (Nw) by multiplying the transfer minimum time (Trq) by the trial subtrahend (Nr) and dividing by the slot time (Ts).

23. The method according to claim 22, further comprising:

reading, by a seventh data station, a transfer addressee data station reception processing time forecast value (T1) and a signal transfer time forecast value as far as the transfer addressee (T2) based on a transfer addressee data station number (STNo) assigned to the data for which transfer is requested from a predetermined list (TBL-1) which includes every transfer addressee data station number;

reading, by the seventh data station, a processing time forecast value (T3) required by the predetermined scheduling;

computing, by the seventh data station, a data packet delay time (T4) as far as the reception of the data packet by the transfer addressee data station based on the data packet length to be transferred, and

determining, by the seventh data station, a transfer minimum time (Trq) by adding together the T1, T2, T3 and T4.

24. The method according to claim 22, further comprising:

subtracting, by a seventh data station, 1 from the slot waiting number and the slot limit number which were added to the transfer request control information of an output which is not complete every said specified time interval;

arranging, by the seventh data station, the transfer request control information in an order determined based on the slot waiting number and slot limit number every time a transfer is requested, and

transferring, by the seventh data station, to the master station transfer request control information for which the slot waiting number becomes 0 or less.

18. A network system transmission control method comprising the steps of:

executing, by a first data station, output requests for data packets every specified time interval;

granting, by a master station, output permission by executing scheduling for the output requests every specified time interval; and

, in the case of multiple transmission stations mutually exchanging data,

generating, by a second data station, a received packet information list by updating packet discrimination information and received packet numbers for every output originator data station every time the second data station receives a data packet from an other data station which has obtained the output permission;

transferring, by the second data station, the contents of the received packet information list to the master station and all other data stations when executing output requests for data packets every said specified time interval regardless of whether or not there is an output data packet, and

enabling judgement of whether or not an outputted data packet has been received by the transfer addressee data station.