Communication method and communications system

• US 6,901,074 B1
• Filed: 12/01/1999
• Issued: 05/31/2005
• Est. Priority Date: 12/03/1998
• Status: Expired due to Term

• Current Assignee: National Institute of Advanced Industrial Science and Technology (Government of Japan)
• Original Assignee: National Institute of Advanced Industrial Science and Technology (Government of Japan), Nobuyuki Yamasaki
• Inventors: Yamasaki, Nobuyuki
• Primary Examiner(s): Nguyen, Brian
• Application Number:
  US09/452,351
• Time in Patent Office: 2,008 Days
• Field of Search: 370/400, 370/401, 370/402, 370/412, 370/413, 370/414, 370/417, 370/418, 370/425, 370/431, 370/432, 370/437, 370/442, 370/447, 370/449, 370/455, 370/458, 370/461, 370/462, 370/465, 370/475, 370/498, 370/536, 370/537, 370216-218, 370/225, 370/228, 370/229, 370/235, 370/242, 370/351, 370/352, 370/357, 370/360, 370389-392, 370/395.1, 370396-397, 370/395.2, 370/395.21, 370/395.3, 370/395.31, 370/395.4, 370/395.41, 370/395.42, 370/396.65
• US Class Current: 370/400
• CPC Class Codes: H04L 12/28 characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks] wireless communication networks H04W ; arrangements for dividing the transmission path H04W40/00
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/22 Alternate routing
• CPC Class Codes: H04L 45/3065 for real time traffic
• CPC Class Codes: H04L 45/44 Distributed routing
• CPC Class Codes: H04L 47/2416 Real-time traffic
• CPC Class Codes: H04L 47/2458 Modification of priorities while in transit

Abstract

A real-time communications system for decentralized management is accomplished which was not implemented conventionally. To achieve this, the following techniques are employed: (1) Overtaking of communication packets based on priority; (2) Path control based on the priority; and (3) Priority change at each node. When carrying out real-time communication between a plurality of information processors, each communication node (information processor) carries out overtaking of the communication packets in accordance with the priority. In the course of this, each communication node can change the priority, and establish different paths for each of the priority.

Claims

1. A communications method in a communications system having one or more communication nodes each of which is provided with an information processor, said communications method comprising the steps of:

accepting an incoming communication packet with a priority at one of the communication nodes; and

controlling, when a plurality of communication packets accepted at the step of accepting at said one of the communication nodes have the same output destination, a communication packet with a higher priority to be outputted first,

wherein said step of controlling comprises the substeps of;

buffering, at said one of the communication nodes, by using a plurality of packet overtaking buffers provided for individual input ports, a communication packet to be overtaken in accordance with the priority when a collision takes place between communication packets;

making an output request from each input port side to one or more output port sides, the output request with the priority assigned to an input communication packet;

carrying out arbitration of output from said each input port side using a priority arbiter for the communication packets which is allocated to each output port; and

outputting an input packet to each output port side independently in accordance with the output arbitration.

2. The communications method as claimed in claim 1, further comprising the step of controlling acceleration or deceleration of the communication packet by changing the priority of the communication packet at said one of the communication nodes.

3. A communications system having one or more communication nodes each of which is provided with an information processor, at least one of the communications nodes comprising:

means for accepting an incoming communication packet with a priority, and

means for controlling, when a plurality of communication packets accepted by the means for accepting have the same output destination, a communication packet with a higher priority to be outputted first,

wherein said control means comprises;

means for buffering, by using a plurality of packet overtaking buffers provided for individual input ports, a communication packet to be overtaken in accordance with the priority when a collision takes place between communication packets;

means for making an output request from each input port side to one or more output port sides, the output request with the priority assigned to an input communication packet;

means for carrying out arbitration of output from said each input port side using a priority arbiter for the communication packets which is allocated to each output port; and

means for outputting an input packet to each output port side independently in accordance with the output arbitration.

4. The communications system as claimed in claim 3, wherein said at least one of the communications nodes further comprises means for controlling acceleration or deceleration of the communication packet by changing the priority of the communication packet.

5. A communications method in a communications system having one or more communication nodes each of which is provided with an information processor, said communications method comprising the steps of:

accepting an incoming communication packet including a network address and a priority at one of the communication nodes; and

outputting a communication packet accepted at the step of accepting at said one of the communication nodes to another communication node in accordance with the network address and the priority of the communication packet, wherein

said step of outputting is able to output, when network addresses of communication packets are the same and priorities of the communication packets are different from each other, the communication packets to different communication nodes in accordance with the priorities of the communication packets,

said step of outputting determines one or more communication nodes to which the accepted communication packet is to be outputted by referring to a routing table by using a pair of the network address and the priority of the accepted communication packet, and outputs the accepted communication packet to the determined communication nodes, wherein

said routing table has correspondence between a pair of a network address and a priority, and one or more communication nodes to which a communication packet is to be outputted, and

said routing table further has correspondence between a pair of a network address and a priority, and a new priority, and

said step of outputting determines, by referring to the routing table by using the pair of the network address and the priority of the accepted communication packet, one or more communication nodes to which the accepted communication packet is to be outputted and a new priority, replaces the priority of the accepted communication packet with the determined new priority, and outputs the accepted communication packet to the determined communication nodes.

6. A communications system having one or more communication nodes each of which is provided with an information processor, at least one of the communications nodes comprising:

means for accepting an incoming communication packet including a network address and a priority; and

means for outputting a communication packet accepted by the means for accepting to one or more communication nodes in accordance with the network address and the priority of the communication packet, wherein

said means for outputting is able to output, when network addresses of communication packets are the same and priorities of the communication packets are different from each other, the communication packets to different communication nodes in accordance with the priorities of the communication packets,

said means for outputting determines one or more communication nodes to which the accepted communication packet is to be outputted by referring to a routing table by using a pair of the network address and the priority of the accepted communication packet, and outputs the accepted communication packet to the determined communication nodes, wherein

said routing table has correspondence between a pair of a network address and a priority, and one or more communication nodes to which a communication packet is to be outputted, and

said routing table further has correspondence between a pair of a network address and a priority, and a new priority, and

said means for outputting determines, by referring to the routing table by using the pair of the network address and the priority of the accepted communication packet, one or more communication nodes to which the accepted communication packet is to be outputted and a new priority, replaces the priority of the accepted communication packet with the determined new priority, and outputs the accepted communication packet to the determined communication nodes.