Communication protocol system

• US 5,425,025 A
• Filed: 03/01/1994
• Issued: 06/13/1995
• Est. Priority Date: 10/30/1990
• Status: Expired due to Term

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Tahara, Tadayuki
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): BLUM, RUSSELL
• Application Number:
  US08/203,767
• Time in Patent Office: 469 Days
• Field of Search: 370/60, 370/94.1, 370/99, 371/32
• US Class Current: 370/394
• CPC Class Codes: H04L 1/0083 Formatting with frames or packets; Protocol or part of protocol for error control
• CPC Class Codes: H04L 1/1657 Implicit acknowledgement of correct or incorrect reception, e.g. with a moving window
• CPC Class Codes: H04L 1/1832 Details of sliding window management
• CPC Class Codes: H04L 1/1848 Time-out mechanisms
• CPC Class Codes: H04L 1/187 Details of sliding window management
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A communication protocol used in a communication utilizing a window system, wherein a transmitting window number, a receiving window number, a transmitting sequence number and a receiving sequence number are provided as items in a message. The transmitting side and receiving side respectively count up the number of times of transmission and reception of messages transmitted and received and also give or provide the counted value to or in a message as the transmitting window number or receiving window number. In addition, transmitting window number is counted up when a number of messages transmitted or received has exceeded the window width, and thereby a number of times of transmission and reception of messages is controlled in units of the window number.

Claims

1. In a window system communication where predetermined messages between a transmitting side and a receiving side used to execute data communication via a packet switching network are defined by a window width, the transmitting side transmits continuously a plurality of messages each having particular regions in the window width and the receiving side returns a response for acknowledgment of reception to the transmitting side when the plurality of messages of the window are received, a communication protocol method comprising the steps of:

(a) providing a transmitting window number, a receiving window number, a transmitting sequence number and a receiving sequence number as items in the particular regions of each of the plurality of messages;

(b) counting a first number of times of transmission of the plurality of messages in the transmitting side to generate a transmitting sequence number;

(c) counting a second number of times of reception of the plurality of messages in the receiving side to generate a receiving sequence number;

(d) incrementing the transmitting window number when one of the transmitting and receiving sequence numbers has exceeded the window width; and

(f) incrementing the receiving sequence number for each successful reception of the plurality of messages in the receiving side and including the receiving sequence number in the response;

(e) controlling transmission and reception using the transmitting and receiving window numbers and the transmitting and receiving sequence numbers.

2. In a window system communication according to claim 1, wherein said step (e) further comprises the substep of transmitting a request for a response from the transmitting terminal to the receiving terminal when the number of continuous transmissions and receptions exceeds a predetermined sequence number.

3. A communication protocol method for use with transmitting and receiving sides, comprising the steps of:

(a) incrementing, in the transmitting side, an internal transmitting sequence value forming an incremented transmit sequence value each time a message is transmitted, the message including a transmitting sequence number which is assigned the incremented transmitting sequence value and a transmitting window number;

(b) incrementing, in the receiving side, an internal receiving sequence value forming an incremented receiving sequence value when the internal receiving sequence value matches the transmitting sequence number;

(c) assigning, in the receiving side, to a receiving sequence number the incremented internal receiving sequence value;

(d) incrementing, in the receiving side, an internal receiving window number forming an incremented internal receiving window number, initializing the internal receiving sequence counter, and sending a response without data to the transmitting side having a receiving window number, indicating normal operation when the internal receiving window number matches the transmitting window number;

(e) incrementing, in the transmitting side, an internal transmitting window number forming an incremented internal transmitting window number and assigning to the transmitting window number the incremented internal transmitting window number when the incremented internal transmitting window number matches the receiving window number received in the response; and

(f) controlling transmission and reception using the transmitting and receiving window numbers and the transmitting and receiving sequence numbers.

4. An apparatus performing a communication protocol, comprising:

first incrementing means for incrementing an internal transmitting sequence value forming an incremented transmit sequence value each time a message is transmitted, the message including a transmitting sequence number which is assigned the incremented transmitting sequence value and a transmitting window number;

second incrementing means for incrementing an internal receiving sequence value forming an incremented receiving sequence value each time the message is received when the internal receiving sequence value matches the transmitting sequence number;

assigning means for assigning to a receiving sequence number the incremented internal receiving sequence value each time the message is received;

third incrementing means for incrementing each time the message is received, an internal receiving window number forming an incremented internal receiving window number, initializing the internal receiving sequence counter, and sending a response without data to the transmitting side having a receiving window number assigned the incremented internal receiving window number, indicating normal operation when the internal receiving window number matches the transmitting window number;

fourth incrementing means for incrementing, each time the response is received, an internal transmitting window number forming an incremented internal transmitting window number and assigning to the transmitting window number the incremented internal transmitting window number when the incremented internal transmitting window number matches the receiving window number received in the response; and

control means for controlling transmission and reception using the transmitting and receiving window numbers and the transmitting and receiving sequence numbers.