Data transmission confirmation by sending frame with command to change transmitter's resend counter when receiver's buffer is full

• US 5,623,602 A
• Filed: 04/09/1993
• Issued: 04/22/1997
• Est. Priority Date: 04/09/1992
• Status: Expired due to Term

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Nakashima, Toshihiro
• Primary Examiner(s): Lee, Thomas C.
• Assistant Examiner(s): DINH, DUNG C
• Application Number:
  US08/044,485
• Time in Patent Office: 1,474 Days
• Field of Search: 395/200, 395/575, 395/182.02, 395/185.01, 395/185.03, 395/200.13, 395/200.14, 395/200.1, 395/200.11, 395/849, 395/250
• US Class Current: 709/235
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/32 by discarding or delaying data units, e.g. packets or frames
• CPC Class Codes: H04L 69/324 in the data link layer [OSI layer 2], e.g. HDLC
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A computer network system includes a plurality of computers and a network connected to the computers for allowing them to interchange data. Each computer has a data send module and a data receive module. The data send module is made up of a means for sending a data frame to the network in response to a send request, a resend number storing means for storing the number of times that the data frame is to be resent, and a means for updating the content of the resend number storing means upon receiving a frame for changing the number of times that the data frame is to be resent from the network. The data receive module includes a receive buffer for storing the data frame received from the network, and a means for sending, when the receive buffer is full, the frame for changing the number of times that the data frame is to be resent to the network.

Claims

1. A computer network system for sending and receiving data by a frame synchronization system, comprising:

a plurality of computers; and

a network connected to said plurality of computers for sending and receiving data;

said plurality of computers each comprising;

a data send module comprising means for sending a data frame to said network in response to a data send request, resend number storing means for storing a resend limit defining a maximum number of times that the data frame may be resent following an unsuccessful sending of the data frame, and means for updating a content of said resend number storing means upon receiving a frame comprising an instruction for changing the resend limit; and

a data receive module comprising a receive buffer for storing the data frame received from said network, and means for sending, when said receive buffer is full, the frame comprising the instruction for changing the resend limit.

2. A system as claimed in claim 1, wherein said data receive module comprises:

a frame send and receive module for sending and receiving a frame to said network;

a receive buffer for storing the frame received by said frame send and receive module;

a received frame decode module for decoding the frame stored in said receive buffer and executing processing for each type of frame received;

a data receive response module for generating a receive response frame matching the frame decoded by each received frame decode module, and delivering a data send request to said frame send and receive module;

a received data disposal module for processing data received from said data receive response module;

a receive buffer control module responsive to end-of-processing information from said received data disposal module for executing first processing which allows said frame send and receive module to access said receive buffer and second processing which determines whether or not said receive buffer is full; and

a resend number change request module for generating, when said receive buffer is full, as determined by said receive buffer control module, the frame comprising the instruction for changing the resend limit and sending the frame comprising the instruction for changing the resend limit to said network via said frame send and receive module.

3. A system as claimed in claim 1, wherein said data send module comprises:

a data send request module for generating a data send request;

a frame send and receive module for sending a data frame in response to the data send request from said data send request module and receiving a frame from said network;

a receive buffer for storing the frame received by said frame send and receive module;

a received frame decode module for decoding the frame stored in said receive buffer and executing processing for each type of frame received;

a data send confirmation module for executing processing which generates a data frame in response to the data send request from said data send request module and delivers the data frame send request to said frame send and receive module, for executing processing which determines that data transmission was successful upon receiving a receive response frame from said network, for executing processing which resends the data frame when the receive response frame is not received within a predetermined period of time, and for executing processing which informs said data send request module of a failure of data transmission when the receive response frame is not received even after the data frame has been repetitively sent, on the basis of a content of said resend number storing means; and

a resend number change module for updating the content of said resend number storing means on the basis of the frame comprising the instruction for changing the resend limit, as decoded by said received frame decode module.

4. A system as claimed in claim 1 or 2, wherein said data receive module comprises means for sending the frame comprising the instruction for changing the resend limit as a broadcast frame.

5. A system as claimed in claim 1, wherein said means for updating a content of said resend number storing means, upon receiving the frame comprising the instruction for changing the resend limit, updates the content of said resend number storing means by replacing the resend limit presently stored with a new resend limit defining a number of times that the data frame may be resent that is greater than the maximum number of times defined by the presently stored resend limit.

6. A method, utilizing a plurality of computers and a network connecting the plurality of computers, for sending and receiving frame synchronized data;

said method comprising the steps of;

sending a data frame to the network in response to a data send request;

storing a resend limit indicative of a number of times that the data frame is to be resent following an unsuccessful sending of the data frame;

updating the resend limit upon receiving a frame comprising an instruction for changing the resend limit from the network;

receiving and storing the data frame sent to the network; and

sending, when a receive module is full, the frame comprising the instruction for changing the resend limit to the network.

7. A method as claimed in claim 6, further comprising the steps of:

generating the data send request;

executing processing which generates the data frame in response to the data send request;

executing processing which determines that data transmission was successful upon receiving a receive response frame from the network;

executing processing which resends the data frame when the receive response frame is not received within a predetermined period of time; and

executing processing which informs of an unsuccessful data transmission when the receive response frame is not received even after said data frame has been resent a number of times corresponding to the resend limit.

8. A method as claimed in claim 6, wherein the frame comprising the instruction for changing the resend limit is sent as a broadcast frame.

9. A method as claimed in claim 6, further comprising the steps of:

decoding a frame received from the network and executing processing specific to each type of frame received;

generating a receive response frame matching the decoded frame;

processing the data frame received from the network;

executing first processing, which opens access to the receive module, in response to an end-of-processing signal, and executing second processing for determining whether or not the receive module is full; and

generating, when the receive module is full, the frame comprising the instruction for changing the resend limit.

10. A method as claimed in claim 6, wherein said step of updating the resend limit comprises increasing the resend limit from a first predetermined value to a second predetermined value that is greater than the first predetermined value.

11. A computer network system for sending and receiving data by a frame synchronization system, comprising:

a plurality of computers; and

a network connected to said plurality of computers for sending and receiving data;

said plurality of computers each comprising;

a data frame transmitter;

a resend number store that stores a value signifying the maximum number of times that the data frame is to be resent; and

an input for updating the value in response to an increase signal for increasing the value; and

a data frame receiver; and

a value change transmitter for sending the increase signal in response to a capacity signal from said data frame receiver;

wherein the increase signal comprises an instruction for increasing the value.

12. A system as claimed in claim 11, further comprising:

a receive buffer for storing a frame received by said data frame receiver;

a received frame decode module for decoding the frame stored in said receive buffer and for executing processing specific to each type of frame received;

a data receive response module for generating a receive response frame matching the frame decoded by said received frame decode module, and delivering a data send request to said data frame receiver;

a received data disposal module for processing data received from said data receive response module;

a receive buffer control module responsive to end-of-processing information from said received data disposal module for executing first processing which allows said data frame receiver to access said receive buffer and second processing which determines whether or not said receive buffer has attained a given capacity; and

a resend number change request module for generating the increase signal when said receive buffer control module determines that the receive buffer has attained the given capacity.

13. A system as claimed in claim 11, further comprising:

a generator for generating a data send request;

a receive module associated with said data frame transmitter for receiving a frame from the network;

a receive buffer associated with said data frame transmitter for storing the frame received by said receive module;

a received frame decode module associated with said data frame transmitter for decoding the frame stored in said receive buffer and for executing processing specific to each type of frame received;

a data send confirmation module for executing processing which generates a data frame in response to the data send request from the generator and delivers a data frame send request to said data frame transmitter, for executing processing which determines that data transmission was successful upon receiving a receive response frame from the network, for executing processing to resend the data frame when the receive response frame is not received within a predetermined period of time, and for executing processing when the receive response frame is not received even after the data frame has been repetitively sent, on the basis of the value stored in said resend number store; and

a resend number change module for updating the value in response to the increase signal as decoded by said received frame decode module.

14. A system as claimed in claim 11, wherein:

said data frame receiver comprises a receive buffer; and

the capacity signal comprises a signal indicating a data capacity of said receive buffer.

15. A system as claimed in claim 14, wherein:

said receive buffer stores a frame received by said data frame receiver; and

further comprising;

a received frame decode module for decoding the frame stored in said receive buffer and for executing processing specific to each type of frame received;

a data receive response module for generating a receive response frame matching the frame decoded by said received frame decode module, and delivering a data send request to said data frame receiver;

a received data disposal module for processing data received from said data receive response module;

a receive buffer control module responsive to end-of-processing information from said received data disposal module for executing first processing which allows said data frame receiver to access said receive buffer and second processing which determines whether or not said receive buffer has attained a given capacity; and

a resend number change request module for generating the increase signal when said receive buffer control module determines that the receive buffer has attained the given capacity.

16. A system as claimed in claim 14, further comprising:

a generator for generating a data send request;

a receive module associated with said data frame transmitter for receiving a frame from the network;

a receive buffer associated with said data frame transmitter for storing the frame received by said receive module;

a received frame decode module associated with said data frame transmitter for decoding the frame stored in said receive buffer and for executing processing specific to each type of frame received;

a data send confirmation module for executing processing which generates a data frame in response to the data send request from the generator and delivers a data frame send request to said data frame transmitter, for executing processing which determines that data transmission was successful upon receiving a receive response frame from the network, for executing processing to resend the data frame when the receive response frame is not received within a predetermined period of time, and for executing processing when the receive response frame is not received even after the data frame has been repetitively sent, on the basis of the value stored in said resend number store; and

a resend number change module for updating the value in response to the increase signal as decoded by said received frame decode module.