Network system, nodes connected thereto and data communication method using same

• US 20060146829A1
• Filed: 12/29/2005
• Published: 07/06/2006
• Est. Priority Date: 01/04/2005
• Status: Abandoned Application

• Current Assignee: Omron Corporation
• Original Assignee: Omron Corporation
• Inventors: Yamada, Hiroaki
• Application Number:
  US11/323,648
• Publication Number:
  US 20060146829A1
• Time in Patent Office: Days
• US Class Current: 370/392
• CPC Class Codes: H04L 12/18 for broadcast or conference , e.g. multicast
• CPC Class Codes: H04L 12/417 with deterministic access, e.g. token passing
• CPC Class Codes: H04L 49/90 Buffering arrangements
• CPC Class Codes: H04L 49/901 using storage descriptor, e.g. read or write pointers

Abstract

A plurality of nodes are connected to a network and share data among them to form a network system. Each node has a communication interface for transmission and reception of data by full duplex transmission through the network and a virtual memory for storing data to be transmitted. Multicast addresses are set to the data to be transmitted in units of frames, and the communication interface serves to transmit data by multicast together with their corresponding multicast addresses. Each node, when data to be received thereby are set, serves to store one or more of multicast addresses of frames containing data to be transmitted from other nodes by multicast and to be received thereby. The communication interface of each node, when receiving frames transmitted by multicast, serves to copy the data of those of the received frames having a multicast address that matches one of the stored multicast addresses and to discard frames with a multicast address that does not match any of the stored multicast addresses.

Claims

1. A network system comprising a network and a plurality of nodes connected thereto, said nodes having data shared in common among said nodes;

said nodes each having a communication interface for transmission and reception of data by full duplex transmission through said network;

said nodes each having a virtual memory for storing data to be transmitted by said node, said data to be transmitted having multicast addresses set thereto in units of frames;

the communication interface, when the node corresponding thereto is transmitting data, serving to transmit said data by multicast together with the multicast addresses corresponding to said transmitted data;

each of said nodes, when data to be received thereby are set, serving to store one or more of multicast addresses of frames containing data to be transmitted from other nodes by multicast and to be received thereby; and

the communication interface of each of said nodes serving, when receiving frames transmitted by multicast, to copy to the corresponding node the data of those of said received frames having a multicast address that matches one of the stored multicast addresses and to discard frames with a multicast address that does not match any of the stored multicast addresses.

2. The network system of claim 1 wherein said network is an Ethernet network.

3. A node adapted to be connected to a network and to share data in common with other nodes connected to said network, said node comprising;

a communication interface for transmission and reception of data by full duplex transmission through said network;

a virtual memory for storing data to be transmitted by the node and multicast addresses in correlation; and

a memory for storing multicast addresses of frames containing those of the data transmitted by multicast from other nodes that are to be received by itself;

wherein said communication interface serves to transmit data by multicast together with said stored multicast addresses and, when frames transmitted by multicast are received, to copy to the node the data in those of said received frames having a multicast address that matches one of said stored multicast addresses and to discard data in those of said received frames having a multicast address not matching any of said stored multicast addresses.

4. A data communication method using a network system with a network and a plurality of nodes connected to said network and adapted to share data in common among said nodes, said method comprising the steps of:

providing each of said nodes with a communication interface for transmission and reception of data by full duplex transmission through said network;

providing each of said nodes with a virtual memory for storing data to be transmitted by said node;

setting multicast addresses to data in units of frames for transmission;

causing the communication interface of one of said nodes to transmit by multicast the data for transmission together with said set multicast addresses;

causing each of said nodes for which data to be received are set, to store multicast addresses of frames containing data that are transmitted from other nodes and intended to be received by said each node; and

causing the communication interface of each of said nodes, when data are thereby received by multicast, to copy to the corresponding node the data contained in those of the frames transmitted by multicast and having a multicast address that matches one of said stored multicast addresses and to discard data in those of said received frames having a multicast address not matching any of said stored multicast addresses.

5. The data communication method of claim 4 further comprising the steps of:

causing each of said nodes to transmit data by assigning a same identification number to a plural number of frames; and

causing each of said nodes, when receiving data, to copy said received data to said each node only after data in said plural number of frames have been received.

6. The data communication method of claim 4 further comprising the steps of:

causing each of said nodes to record node-identifying data for identifying a data-transmitting node that transmits data to be received by itself and address data of the virtual memory of said data-transmitting node; and

causing an inquiry to be made to said data-transmitting node regarding multicast address based on said recorded address data and obtaining said multicast address.

7. The data communication method of claim 5 further comprising the steps of:

causing each of said nodes to record node-identifying data for identify a data-transmitting node that transmits data to be received by itself and address data of the virtual memory of said data-transmitting node; and

causing an inquiry to be made to said node transmitting data regarding multicast address thereof based on said recorded address data and obtaining said multicast address.

8. A network system comprising a network and a plurality of nodes connected thereto through a switching hub, said nodes having data shared in common among said nodes;

said nodes each having a communication interface for transmission and reception of data by full duplex transmission through said network;

said nodes each having a virtual memory for storing data to be transmitted by said node, said data to be transmitted having multicast addresses set thereto in units of frames;

the communication interface, when the node corresponding thereto is transmitting data, serving to transmit said data by multicast together with the multicast addresses corresponding to said transmitted data;

each of said nodes, when data to be received thereby are set, serving to store one or more of multicast addresses of frames containing data to be transmitted from other nodes by multicast and to be received thereby;

the communication interface of each of said nodes serving, when receiving frames transmitted by multicast, to copy to the corresponding node the data of those of said received frames having a multicast address that matches one of the stored multicast addresses and to discard frames with a multicast address that does not match any of the stored multicast addresses; and

each of said nodes serving to transmit data cyclically at transmission timing of itself to thereby share the transmitted data with the others of said nodes.

9. The network system of claim 8 wherein each of said nodes is adapted, when transmitting data by dividing said data into a plural number of frames within a same communication cycle, to assign a same identification number to said frames and, when receiving data, to copy said received data to said each node only after data in a number same as said plural number of frames have been received.