Data repeater and multiplex communication system using the same

• US 6,879,563 B1
• Filed: 02/17/2000
• Issued: 04/12/2005
• Est. Priority Date: 02/18/1999
• Status: Expired due to Term

• Current Assignee: DENSO Corporation, Nippon Soken, Inc. (DENSO Corporation), Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: DENSO Corporation, Nippon Soken, Inc. (DENSO Corporation), Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Tomita, Kenji, Wakamatsu, Toshihiro, Hayashi, Ikuo, Sakai, Kazunori, Kamiya, Masachika, Kishigami, Tomohisa, Sato, Yoshihisa, Honda, Hiroshi, Kume, Masato, Yagyu, Mikito
• Primary Examiner(s): Pezzlo, John
• Assistant Examiner(s): Levitan, D
• Application Number:
  US09/505,704
• Time in Patent Office: 1,881 Days
• Field of Search: 370/395.42, 370/395.43, 370/412, 370/395.7, 370/395.71, 370/226, 370/243, 370/246, 370/401
• US Class Current: 370/246
• CPC Class Codes: H04L 12/4625 Single bridge functionality, e.g. connection of two networks over a single bridge
• CPC Class Codes: H04L 25/20 Repeater circuits; Relay circuits
• CPC Class Codes: H04L 47/50 Queue scheduling
• CPC Class Codes: H04L 47/56 implementing delay-aware scheduling
• CPC Class Codes: H04L 47/6215 Individual queue per QOS, rate or priority
• CPC Class Codes: H04L 49/90 Buffering arrangements
• CPC Class Codes: H04L 49/9021 Plurality of buffers per packet
• CPC Class Codes: H04L 49/9084 Reactions to storage capacity overflow

Abstract

A multiplex communication system having a data repeater, which can prevent data from being lost so as to improve reliability of data communication, when a data repeater of a multiplex communication system repeats data. A multiplex communication system is made up of a plurality of communication groups including a plurality of communication lines and a data repeater. The data repeater is made up of receiving buffers, sending buffers, a data controller and a transfer-address table. The data controller selects multiplex communication lines through which the received data is to be repeated and transfers the received data thereto. The data controller has a priority-reset means for increasing a priority of a received data before being sent. The priority-reset means prioritizes a sending of the data from the data repeater, even if the data sent from the data repeater collides with the other data on the multiplex communication lines through which the received data is to be repeated. In this way, the priority-reset means prevents the data waiting for being sent in the data repeater from being lost by being overwritten with newly received data.

Claims

1. A data repeater for repeating plural types of data and being interfaced with a plurality of multiplex communication lines through a receiving buffer and a sending buffer for transmitting data whose priority is previously set based on data type, comprising:

a data controller for selecting a certain multiplex communication line of the multiplex communication lines through which received data that is received from one of the multiplex communication lines other than the certain multiplex communication line is to be repeated and for transmitting the received data to the certain multiplex communication line, the data controller for preventing direct transmission of data between respective ones of the plurality of multiplex communication lines over which data is being transmitted and received by causing the received data to be temporally held from when the data is received by the receiving buffer through when the received data is transmitted from the receiving buffer to the sending buffer to when the data is transmitted by the sending buffer; and

priority-reset means within the data controller for resetting a priority of the received data to a priority higher than an original priority of the received data when it is received, when the received data is transmitted from the receiving buffer to the sending buffer,

wherein the priority-reset means resets the priority of the received data to a predetermined constant priority higher than original priorities of other data within the certain multiplex communication line.

2. A data repeater according to claim 1, wherein:

the priority-reset means is prospectively provided to each one of the plurality of multiplex communication lines through which the received data is to be repeated, and

the priority-reset means resets the priority of the received data to a predetermined constant priority higher than original priorities of other data within the certain communication line.

3. A data repeater according to claim 1, wherein:

the predetermined constant priority to which the priority-reset means resets the priority of the received data is a maximum priority that the priority-reset means can reset.

4. A data repeater for repeating plural types of data and being interfaced with a plurality of multiplex communication lines through a receiving buffer and a sending buffer for transmitting data whose priority is previously set based on data type, comprising:

a data controller for selecting a certain multiplex communication line from the plurality of multiplex communication lines through which received data that is received from one of the plurality of multiplex communication lines other than the certain multiplex communication line is to be repeated and for transmitting the received data to the certain multiplex communication line, the data controller for preventing direct transmission of data between respective ones of the plurality of multiplex communication lines over which data is being transmitted and received by causing the received data to be temporally held from when the data is received by the receiving buffer through when the received data is transmitted from the receiving buffer to the sending buffer to when the data is transmitted by the sending buffer; and

priority-reset means within the data controller for resetting the previously set priority of the received data to a priority higher than a predetermined priority before transmitting the received data when the received data is transmitted from the receiving buffer to the sending buffer,

wherein the priority-reset means resets the priority of the received data to a predetermined constant priority higher than original priorities of other data within the certain multiplex communication line.

5. A data repeater according to claim 4, wherein:

the priority-reset means is prospectively provided to each of the plurality of multiplex communication lines through which the received data is to be repeated, and

the priority-reset means resets the priority of the received data to a predetermined constant priority higher than priorities of other data within the certain communication line.

6. A data repeater according to claim 4, wherein:

the predetermined constant priority to which the priority-reset means resets the priority of the received data is a maximum priority that the priority-reset means can reset.

7. A multiplex communication system comprising:

a plurality of communication groups each having;

a multiplex communication line for transmitting data whose priority is previously set based on data type; and

a communication node connected to the multiplex communication line; and

a data repeater interfaced with the multiplex communication lines of the communication groups through a receiving buffer and a sending buffer, for repeating plural types of data, comprising;

a data controller for selecting a certain multiplex communication line of the multiplex communication lines through which received data that is received from a communication line of other than the certain multiplex communication line is to be repeated and for transmitting the received data to the certain multiplex communication line, the data controller having priority-reset means for resetting the previously set priority of the received data to a priority higher than a predetermined priority before transmitting the received data, the data controller for preventing direct transmission of data between respective ones of the plurality of multiplex communication lines over which data is being transmitted and received by causing the received data to be temporally held from when the data is received by the receiving buffer through when the received data is transmitted from the receiving buffer to the sending buffer to when the data is transmitted by the sending buffer;

wherein the priority-reset means resets the priority of the received data to a predetermined constant priority higher than original priorities of other data within the certain multiplex communication line.