Network address managing method and system

Abstract: A network address managing system comprises a plurality of ports distributed over a network to input and output information therethrough, and a plurality of nodes connectable to the plurality of ports in a plug-in manner, respectively, thereby managing node addresses indicating positions of the plurality of nodes. Each of the plurality of ports comprises a port identifier storage section for setting a unique port identifier therein, a node address storage section for storing a node address transferred over the network therein, and a port control section for determining a coincidence between a port identifier ID sent over the network along with the node address and the port identifier ID stored in the port identifier storage section, storing the node address transferred thereto in the node address storage section upon determination of the coincidence, and, when some node is connected to the port, transferring the stored node address to that node. Each of the plurality of nodes comprises a node address storage section for storing a node address therein, and a node control section for storing the node address transferred from the connected port into the node address storage section of the node.

Description: The present invention relates to a network address managing method and system for managing network (node) addresses at node positions in a network system which comprises ports connected to the network and nodes connectable to the ports in a plug-in manner. Fig. 1 is a block diagram showing the configuration of a network system which adopts a conventional network address managing system. In Fig. 1, the reference numeral 1 denotes a plurality of ports connected to network cables N1, N2 for input/output of information, 2 a plurality of nodes connectable to the ports 1 in a plug-in manner, and 3 gate ways (or bridges) for interconnecting the network cables N1 and N2. Fig. 2 is a representation showing a correspondence table 5 between node names and node addresses. The node 1 of a node name A is located at a node address 1-1, the node 1 of a node name B at a node address 1-2, the node 1 of a node name C at a node address 2-1, and the node 1 of a node name D at a node address 2-2, respectively. Processing by means of that conventional network address managing system will now be described. When the nodes 2 are connected to the network cables N1, N2 via the ports 1, a management operator of the network assigns respective nodes their node addresses corresponding to node names, as exemplarily shown in the correspondence table 5 of Fig. 2, for uniquely identifying the nodes throughout the network. Sharing of the correspondence table 5 allows each node 1 to know the node address of the node 1 to be communicated and carry out communication with that node 1. The above conventional network address managing system is problem free in the case that the network configuration is fixed and does not change. However, when the nodes are optionally connectable to the ports in a plug-in manner, the nodes can be easily moved from network to network, which leads to the problem described below. Namely, whenever any of the nodes is moved among networks, the management operator of the system must update the correspondence table between node names and node addresses for each network without causing a contradiction in the table and, as a result, the burden imposed on the management operator is increased. More specifically, in Fig. 1, each node 2 incorporates therein a node address storage section 4 to store its own address, and is connected to the network cable N1 or N2 via the port 1. By connecting a number of nodes to the respective network cables in such a manner, the nodes can be distributed over the network. Looking at a network environment including the nodes distributed therein, each node 2 holds in the node address storage section 4 a node address used for identifying itself in the network, and is also connected to the network cable N1 or N2 via the port 1. Thus, the nodes 2 on the network are connected to the network cables N1, N2 via the respective ports 1 and hold in their node address storage sections 4 respective node addresses uniquely assigned throughout the network. While each node is identified on the network using its node address, the node is connected to the port in a plug-in manner and thus portable. When the node is connected to another network, the content of the node address storage section 4 is corrected because of a different node address assigned thereto. Since the conventional ports just connect the nodes and the network cables, none of the nodes can identify to which port out of the numeral ones it is connected. In order to identify the node, therefore, it is required for the node to directly hold the node address corresponding to the port to which it is connected. Furthermore, in the case that the node is connected to another port in a plug-in manner and moved to another network, the node address must be updated so as to correspond to the port to which it has been newly connected. To solve the above problem, there has so far been disclosed "an adress determining system" in Japanese Patent Public Disclosure (Kokai) No. 1-166640. With this system, a star connection LAN system includes a network extension unit interconnecting respective terminals wherein a local address transferred to the terminal is initially set by setting a dip switch or the like. When a first terminal is connected to the LAN system, the initially set local address is transferred to the first terminal and when a next terminal is connected to the LAN system, the initially se local address is counted up and the resulting local address is transferred to the newly connected next terminal. As a result, there are a plurality of network extension units each of which is required to initially set the local address, and set a new local address by hardare means in need of updating to another local address. The incidental work or procesing and address management become more intricate as the number of units increases. EP-A-00 82 889 relates to a local communication network, wherein stations (nodes) can be attached by plugging via extension lines and individual ports to main transmission lines. Each port has a physical address or local identification key. Means are provided for transmitting the local key of a port to a station when it is plugged into the extension lines of this port. The local key is stored in a key register provided in the station. The key can either be used as the single permanent address of the station, or it can be used as a system internal address for network maintenance procedures with an external system address additionally assigned. The port is provided with a ROM for storing the local key. The key can only be changed by replacing the ROM. The present invention has been made in view of solving the problem mentioned above, and is to provide a network address managing method which does not require a management operator to manage network addresses resulting from the movement ofnodes. Another object of the present invention is to provide an intelligent port which can eliminate the need of changing node addresses on the node side even if nodes are moved to anywhere, and can proberly set any arbitrary node addresses to each port, without taking into account the network configuration. In a network address managing method according to the present invention, a correspondence table between port identifiers and node addresses is prepared, and the node addresses are assigned to respective ports having the corresponding port identifiers. When one node is connected to some port ina plug-in manner, a correspondence between a node name an a node address is given via the port identifier for management of the node-address at which the node is positioned. Thus, with the method of the present invention, the node address is assigned to the port having the corresponding port identifier in accordance with the correspondence table. Upon connection of one node to a port, a port identifier unique to the port operates to provide a correspondence between the node name and the node address. This enables it to manage the network addresses at the respective node positions. An intelligent port according to the present invention is used in a network system wherein nodes are connectable in a plug-in manner to ports distributed over a network, and is constructed by incorporating in each of the ports both a port ID storage section for setting a unique port identifier ID therin, and a control section for determining a coincidence between the set port identifier ID and a port identifier ID sent over the network along with a node address, storing the node address in the node address storage section upon determination of the coincidence, and, when some node is connected to that port, transferring the stored node address to the node for storage therein. The control section of each intelligent port according to the present invention determines a coincidence between the port identifier ID sent over the network along with the node address and the port identifier ID stored in the port ID storage section. When the coincidence is determined, it updates the node address already stored in the node address storage section with the node address sent thereto. Upon connection of a node to that port, the updated node address is transferred to the node. Therefore, the node can automatically update the node address in the node at the connection timing of the node, without having to recognize the node address set on the port side. In other words, according to the present invention, since the correspondence table between the port identifiers and the node addresses is prepared, and the node addresses are assigned to the respective fixed ports having the corresponding port identifiers in the network, the correspondence between the node name and the node address can be automatically created in pair even if the node is moved over the network. As a result, it is possible to automate management of the node addresses at the node positions, and thus greatly the burden imposed on a management operator of the network. Also, according to the present invention, since the port holds the node address so that the node address may be automatically set in the node upon connection of the node to the port, it is to possible to prevent an increase in the node address management operation incidental to an improved portability of nodes. Fig. 1 is a block diagram showing the configuration of a network system which adopts a conventional network address managing system; Fig. 2 is a representation showing a correspondence table between node names and node addresses in the conventional system of Fig. 1; Fig. 3 is a block diagram conceptually showing the configuration of a network system which adopts a network address managing system according to one embodiment of the present invention; Fig. 4 is a representation showing a correspondence table between port ID's and node addresses in the system of the embodiment shown in Fig. 3; and Fig. 5 is a block diagram showing the configuration of the node and the port in the system of the embodiment shown in Fig. 3. Fig. 3 is a block diagram showing the configuration of a network system which adopts a network address managing system according to one embodiment of the present invention. In Fig. 3, the identical components to those in Fig. 1 are denoted by the same reference numerals and will not be described again. Referring to Fig. 3, nodes 2 are connected to network cables N1, N2 via intelligent ports 5 having unique port identifiers (ID) such as α, β, γ, δ, ..., respectively. The network cables N1, N2 are interconnected via gate ways (or bridges) 3. Fig. 4 illustrates a correspondence table 4 between port ID's and node addresses. In the correspondence table, α, β, γ, δ are port identifiers, and 1-1, 1-2, 2-1, 2-2 are node addresses indicating positions of the nodes 2 given with node names A, B, C, D and connected to the ports having their port identifiers α, β, γ, δ, respectively. Processing in the network address managing system of this embodiment will now be described below. When constructing a network, a management operator of the network prepares a correspondence table between port ID's and node addresses, like that shown in Fig. 4, for identifying the nodes 2, which is shared within the network. This correspondence table is not changed unless a port is added to or deleted from the system. Because communication is carried out among the nodes 2, there must be known a node address corresponding to a node to be communicated with. This is achieved by the port 5 informing the node address to the node 2 when the node 2 is plugged into the port 5. Thus, the node 2 receives the node address from the port 5 upon its connection to the port 5, whereby the correspondence between the node name and the node address is determined via the port identifier in the correspondence table in one-to-one relation. Stated otherwise, with a sharing of correspondence between node names and node addresses in the system, the same information as given by the conventional correspondence table, such as that shown in Fig. 2, is automatically created in the node 2. Consequently, correspondence between node names and node addresses can be automatically updated in pairs upon movement of the nodes 2 connectable to the ports 5 in a plug-in manner, making it possible to reduce the burden imposed on the management operator. Fig. 5 is a block diagram showing the configuration of the network system, in which the intelligent port 5 used in the embodiment of Fig. 3 is shown in more detail. As with the above, in Fig. 5, the node 2 is connected to the network cable N1 by being plugged into the intelligent port 5. The node 2 incorporates therein a node address storage section 4, and a node control section 6 for transferring node address information to the node address storage section 4 under control. The port 5 has a port control section 7, a port ID storage section 8 and a node address storage section 9 on the port side, the node address storage section 9 holding the node address. At the timing when the node 2 is connected to the port 5, the node address in the port-side node address storage section is transferred to the node 2 by the port control section 7 and held in the node-side node address storage section 4. Operation of the embodiment shown in Fig. 5 will be described below. The port control section 7 determines whether or not the port identifier ID stored in the port ID storage section 8 coincides with a port identifier ID sent over the network along with a node address. When coincidence therebetween is determined, the port control section 7 operates to receive the node address which has been sent over the network and to store it in the node address storage section 9. When it is required to update the node address already stored, a new update node address is sent over the network cable N1 along with the port identifier ID of the port in which the node address to be updated is stored. Consequently, the port control section 7 of the port 5, which has the port ID storage section 8 storing the same port identifier ID as that sent, takes in the update node address and stores it in the node address storage section 9. After the node address storage section 9 of the port 5 has acquired and stored the node address in such a manner, when the node 2 is connected to the port 5, the port control section 7 first transfers the node address information stored in the port-side node address storage section 9 to the node 2, and the node control section 6 of the node 2 then stores the node address information in the node-side node address storage section 4.

Claims: A network address managing method for use in a network system including a plurality of ports (5) distributed over a network to input and output information therethrough with a plurality of port identifiers being assigned to said plurality of ports (5), respectively, and a plurality of nodes (2) connectable to said plurality of ports (5) in a plug-in manner, respectively , thereby managing node addresses indicating positions of said plurality of nodes (2) characterized by the steps of: preparing a correspondence table between said plurality of port identifiers adapted to identify said plurality of ports (5) and said node addresses, assigning the corresponding node addresses to said plurality of ports (5) already assigned with said port identifiers, respectively, based on said correspondence table, and determining a correspondence between said node (2) and said node address via said port identifier, when said node (2) is connected to said port (5), and transferring the node address to said node (2). A network address managing system comprising a plurality of ports (5) distributed over a network to input and output information theretrough, and a plurality of nodes (2) connectable to said plurality of ports (5) in a plug-in manner, respectively, thereby managing node addresses indicating positions of said plurality of nodes (2), said plurality of ports (5) each comprising a port identifier storage section (8) for setting a unique port identifier therein and said plurality of nodes (2) each comprising a node address storage section (4) for storing a node address therein, and a node control section (6) for storing the node address transferred from said connected port (5) into said node address storage section (4) of said node (2), characterized in that each of said plurality of ports (5) further comprises: a node address storage section (9) for storing a node address transferred over said network therein, and a port control section (7) for determining a coincidence between a port identifier ID sent over said network along with said node address and the port identifier ID stored in said port identifier storage section (8), storing the node address transferred thereto in said node address storage section (9) upon determination of the coincidence, and, when some node (2) is connected to said port (5), transferring the stored node address to that node (2).

Inventors: KANDA AKIRA, KOMATSU TAKAO, KANDA, AKIRA,, KOMATSU, TAKAO,, Kanda, Akira, c/o Computer Seisakusho, Komatsu, Takao, c/o Computer Seisakusho
Applicants: MITSUBISHI ELECTRIC CORP, MITSUBISHI DENKI KABUSHIKI KAISHA
Application year: 1991
Main classification: H04L12
IPC codes: H04L12