Method of updating network reconfiguration information exchanged between a host computer and a communication control processor

What is claimed is:

1. A method of processing reconfiguration information for a network system including at least one host computer provided with network configuration definition information and a dictionary file for storing a plurality of reconfiguration directories each including a reconfiguration designating data for defining a relation between said network and a resource to be deleted from or added to said network, a communication control processor connected to said host computer, and a plurality of resources connected to said communication control processor, said network reconfiguration information processing method comprising the steps of:

supplying, by an operator, a new reconfiguration directory to said host computer;

inputting by said operator a reconfiguration command designating said new reconfiguration directory for instructing said host computer to update said network configuration definition information; and,

responsive to said reconfiguration command, reconfiguring said network configuration definition information by said host computer in accordance with the reconfiguration designating data defined within said new reconfiguration directory designated by said reconfiguration command, and storing said new configuration directory in said directory file.

2. A network reconfiguration information processing method for use with a network system including at least one host computer provided with network configuration definition information and a directory file for storing a plurality of reconfiguration directories each including at least a reconfiguration designating data for defining a relation between said network and a resource to be deleted from or added to said network, a communication control processor connected to said host computer, and a plurality of resources connected to said communication control processor, the network reconfiguration information processing method comprising the steps of:

supplying, by an operator of the network system, a reconfiguration directory to said host computer to add the reconfiguration directory in said directory file;

inputting, by said operator, a reconfiguration command for instructing said host computer to update said network configuration definition information;

responsive to said reconfiguration command, reconfiguring said network configuration definition information, by said host computer, in accordance with a reconfiguration designating data defined within said reconfiguration directory which is designated by said reconfiguration command;

inputting, by said operator, a cancel command designating a one of said reconfiguration directories stored in said directory file, instructing said host computer to cancel at least a part of already executed reconfigurations of said network configuration definition information; and,

responsive to said cancel command, performing a cancellation of a part of the reconfiguration of said network configuration definition information already executed in accordance with said defined reconfiguration designating data within said designated reconfiguration directory, to restore said network configuration definition information to a state before the reconfiguration, and to delete a one of said reconfiguration directories from said directory file in accordance with the reconfiguration designating data within a reconfiguration directory designated by said cancel command.

3. The network reconfiguration information processing method according to claim 2, further comprising, when said designated reconfiguration directory contains said reconfiguration designating data for a plurality of resources, the steps of:

executing the reconfiguration of said network configuration definition information, by said host computer, in response to said reconfiguration command so as to sequentially add or delete a resource to or from said network, in the order that said reconfiguration designating data was described in said reconfiguration directory; and,

executing the cancellation of the reconfiguration of said network configuration definition information, by said host computer, in response to said cancel command in the reverse order of having described said reconfiguration designating data in said reconfiguration directory.

4. The network reconfiguration processing method according to claim 2, further comprising when the reconfiguration designating data within said directory designated by said reconfiguration command or said cancel command relates to a source to be connected to said communication control processor, the steps of:

communicating, by said host computer to said communication control processor, a control command instructing the communication control processor to reconfigure network configuration definition information stored in said communication control processor in accordance with said reconfiguration designating data; and,

in response to said control command, reconfiguring, in said communication control processor the network configuration definition information stored in said communication control processor.

5. The network reconfiguration information processing method according to claim 4, further comprising, when the reconfiguration designating data within said designated reconfiguration directory relates to a plurality of resources, the steps of:

said host computer and said performing said reconfiguration of said network configuration definition information by said host computer and said communication control processor such that a resource is sequentially added to or deleted from said network, in an order that said reconfiguration designating data was described in said reconfiguration directory; and,

cancelling the reconfiguration of said network configuration definition information, by said host computer and said communication control processor, in a reverse order of that described by said reconfiguration designating data in said reconfiguration directory.

6. The network reconfiguration information processing method according to claim 2, further comprising the steps of:

storing by said host computer said reconfiguration command in a reconfiguration history file; and

after executing said cancel command, deleting by said host computer a reconfiguration command corresponding to said reconfiguration directory designated by said cancel command, from said reconfiguration history file.

7. The network reconfiguration information processing method according to claim 6, further comprising:

maintaining, in said host computer, original network configuration definition information; and,

when said host computer restarts upon loading a program, said host computer sequentially reconfigures said original network configuration definition information in accordance with reconfiguration commands read out from said reconfiguration history file to generate current network configuration definition information.

8. A method of processing reconfiguration information in a network system including a plurality of host computers at least one of which operates as a master while others operate as slaves, each of said host computers being provided with configuration definition information and a directory file for storing a plurality of reconfiguration directories, at least one communication control processor provided with configuration definition information and commonly connected to said plurality of host computers, and a plurality of resources connected to said plurality of host computers, and a plurality of resources connected to said communication control processor, said network reconfiguration information processing method comprising the steps of:

supplying, to each of said host computers by an operator of the network system, a reconfiguration directory, said reconfiguration directory including at least one reconfiguration designating data for defining a relation between said network and a resource to be deleted from or added to said network;

issuing, by said operator, a reconfiguration command designating said reconfiguration directory to each of said host computers;

responsive to said reconfiguration command, reconfiguring said network configuration definition information in accordance with the reconfiguration designating data within said reconfiguration directory designated by said reconfiguration command and storing said designated reconfiguration directory in said directory file, by each of said host computers, respectively; and,

when said reconfiguration designating data within said reconfiguration directory corresponds to a resource to be connected to said communication control processor, transmitting, from said master host computer to said communication control processor, a control command instructing said communication control processor to reconfigure said network configuration definition information in said communication control processor in accordance with said reconfiguration designating data.

9. The network reconfiguration information processing method according to claim 8, further comprising the steps of:

issuing, to each of said plurality of host computers by the operator, a cancel command designating at least one of said reconfiguration directories stored in said directory file, for instructing a canceling of at least a part of already executed reconfiguration of said network configuration definition information;

responsive to said cancel command, cancelling at least a part of the reconfiguration directories of said network configuration definition information, by each of said host computers, so as to restore said network configuration definition information to a state as before the recognition already executed in accordance with the reconfiguration designating data within said designated reconfiguration directory, and deleting said designated reconfiguration directory from said directory file, respectively; and,

when said reconfiguration designating data within said reconfiguration directory designated by said cancel command corresponds to a resource of said communication control processor, transmitting, from said master host computer to said communication control processor, a control command instructing said communication control processor to cancel a part of the reconfiguration of said network configuration definition information of said communication control processor in accordance with the reconfiguration designating data.

10. The network configuration information processing method according to claim 9, further comprising, when said reconfiguration designating data within said designated reconfiguration directory corresponds to a plurality of resources, the steps of:

executing the reconfiguration of said network configuration definition information of each of said host computers and said communication control processor in response to said reconfiguration command so as to sequentially add or delete a resource to or from said network in the order that said reconfiguration designating data was described in said reconfiguration directory; and

executing the cancellation of the reconfiguration of said network configuration definition information of each of said host computers and said communication control processor in response to said cancel command so as to sequentially add or delete a resource to or from said network in the reverse order of said reconfiguration designating data in said reconfiguration directory.

11. The network reconfiguration information processing method according to claim 9, further comprising the steps of:

storing, by each of said host computers, said reconfiguration command in a reconfiguration history file; and,

after executing said cancel command, deleting, by each of said host computers, a reconfiguration command corresponding to said reconfiguration directory designated by said cancel command, from said reconfiguration history file.

12. The network reconfiguration information processing method according to claim 11, further comprising:

storing, in each of said host computers, original network configuration definition information; and,

when said host computer restarts upon loading a program, each of said plurality of host computers sequentially reconfigures said original network configuration definition information in accordance with said reconfiguration command read out from said reconfiguration history file to generate current network configuration definition information.

13. The network reconfiguration information processing method according to claim 10, further comprising, when said cancel command has been executed normally, each of said host computers deletes at least one of said reconfiguration commands corresponding to said reconfiguration directory by said cancel command, from said reconfiguration history file.

14. A method of processing reconfiguration information in a network system including a plurality of host computers at least one of which operates as a master and others operate as slaves, each of said plurality of host computers being provided with configuration definition information and a directory file for storing a plurality of reconfiguration directories, at least one communication control processor provided with configuration definition information related thereto and commonly connected to said host computers, and a plurality of resources connected to said communication control processor, said network reconfiguration information processing method comprising the steps of:

inputting to a first one of said host computers a command designating a one of said plurality of reconfiguration directories for instructing a reconfiguration of said network configuration definition information of said first host computer, said reconfiguration directory including a reconfiguration designating data related to at least one resource to be added to or delete from said network;

reconfiguring, by said one host computer, said network configuration definition information of said first host computer in accordance with a format of said inputted command and the contents of said designated reconfiguration directory;

when said first host computer is a master and said reconfiguration designating data within said designated reconfiguration directory corresponds to a resource of said communication control processor, transmitting, from said master host computer to said communication control processor, a control command instructing said communication control processor to reconfigure said network configuration definition information of said communication control processor in accordance with the format of said inputted command and the content of said reconfiguration designating data, said control command including a reconfiguration directory, and an indicator for indicating that said reconfiguration directory is the last one to be processed by said communication control processor;

reconfiguring the network configuration information of said communication control processor in response to said control command, by said communication control processor;

updating, by said communication control processor, first status information stored in correspondence with said reconfiguration sequence number in accordance with whether said communication control processor has successfully reconfigured said network configuration information, and transmitting, from said communication control processor to said master host computer, a response message including information representative of whether said reconfiguring of said network configuration information has been executed successfully; and,

updating, by said master host computer, second status information stored in correspondence with said reconfiguration sequence number in accordance with the contents of said response message received from said communication control processor.

15. The network reconfiguration information processing method according to claim 14, further comprising the steps of:

in response to a request from said master host computer after the operation of said master host computer restarts, informing said master host computer, from said communication control processor, of all reconfiguration numbers and said first status information stored in said communication control processor; and,

comparing, by said master host computer, said reconfiguration sequence numbers and said first status information received from said communication control processor with reconfiguration sequence numbers and second status information stored in said master host computer respectively, and specifying in accordance with the comparison result, a reconfiguration directory for which reconfiguration should be re-executed.

16. The network reconfiguration information processing method according to claim 14, further comprising the steps of:

in response to a request from said master host computer after the operation of said host computer restarts, informing said master host computer, from said communication control processor, of all reconfiguration numbers and said first status information stored in said communication control processor;

comparing, by said master host computer, said reconfiguration sequence numbers and said first status information received from said communication control processor with reconfiguration sequence numbers and said second status information stored in said master host computer; and,

outputting a message for an operator, by said master host computer, when the comparison result indicates a presence of an inconsistency between said reconfiguration sequence numbers.

Description Submit all comments and votes

BACKGROUND OF THE INVENTION

The present invention relates to a method of processing network reconfiguration information. More particularly, the present invention relates to a method of processing reconfiguration information of a network composed of at least one host computer, a communication control processor (hereinafter called CCP) connected to the host computer, and a plurality of resources connected to the CCP, suitable for dynamically changing the network configuration information of the host computer and CCP under operation.

In a conventional technique for dynamically changing the network configuration information of a CCP, there is disclosed, for example, in Japanese Patent Laid-open Publication JP-A-63-156264, a reconfiguration information processing system in which, as a reconfiguration command is entered from a host computer, the reconfiguration data of the host computer is sent to the CCP which in turn dynamically changes its own reconfiguration definition information in accordance with the reconfiguration data sent from the host computer. This Publication also discloses that the host computer sequentially stores inputted reconfiguration commands in a history infoldnation file, and when an NCP load module is loaded to the CCP, the reconfiguration data associated with the previously entered reconfiguration commands and read from the history information file is sent to the NCP, so that the CCP automatically reconfigure its original network configuration definition information as if the reconfiguration commands were actually entered again.

In a computer network, if for example the reconfiguration information designated by the reconfiguration command contradicts with the physical network structure to be actually changed, it becomes necessary to change the reconfiguration information to the proper information. However, the above-described example technique does not disclose an effective method of changing such a defective reconfiguration command to a proper one.

Furthermore, according to the above-described example technique, the network configuration information at a CCP side becomes coincident with that at a host computer when the CCP restarts its operation. However, if the host computer restarts its operation upon loading a program while the CCP is already operating, the host computer does not send the reconfiguration data to the CCP. Accordingly, if there is a reconfiguration command whose reconfiguration process failed previously at the CCP because of some trouble, there occurs a problem that the host computer restarts, having an inconsistence of configuration definitions between the host computer and CCP.

Still further, in a network arrangement having a single CCP connected to a plurality of host computers, consider the case where a host computer having operated as a slave is changed to a master. In this case, if the new master host computer happens to forget entering a necessary reconfiguration command existing in the past, there occurs an inconsistence of reconfiguration definition information between the master host computer and CCP.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a method of processing configuration definition information of a network composed of at least one host computer, and at least one CCP, capable of dynamically and easily changing the network configuration definition information of both the host computer and CCP.

It is another object of the present invention to provide a method of processing network configuration definition information, capable of canceling an erroneous reconfiguration of configuration definition information caused upon execution of a reconfiguration command and easily correcting the reconfiguration definition command to a proper one.

It is a further object of the present invention to provide a method of processing configuration definition information of a network composed of a plurality of host computers and at least one CCP commonly connected to the plurality of host computers, one of which operates as a master and the others operates as slaves, capable of easily correcting an inconsistence of network configuration definition information between each host computer and CCP.

In order to achieve the above objects, a method of processing reconfiguration information for a network according to the present invention comprises the steps of:

arranging a reconfiguration directory to a host computer, the reconfiguration directory including at least one reconfiguration designating data for defining a relation between the network and a resource to be deleted from or added to the network;

designating the reconfiguration directory and giving a reconfiguration command for reconfigurating the network configuration definition information, to the host computer; and

responsive to the reconfiguration command, causing the host computer to reconfigure the network configuration definition information in accordance with the defined reconfiguration designating data within the reconfiguration directory designated by the reconfiguration command.

The network reconfiguration information processing method according to the present invention, further comprises the steps of:

storing the reconfiguration directory in a directory file;

designating one of the reconfiguration directories stored in the directory file, and giving to the host computer a cancel command for canceling the already executed reconfiguration of the network configuration definition information; and

responsive to the cancel command, causing the host computer to cancel the reconfiguration of the network configuration definition information already executed in accordance with the defined reconfiguration designating data within the designated reconfiguration directory, restore the network configuration definition information before the reconfiguration, and delete the designated reconfiguration directory from the directory file.

In this case, if the designated reconfiguration directory contains the reconfiguration designates data for a plurality of resources: the reconfiguration of the network configuration definition information to be executed in response to the reconfiguration command is executed such that a resource is sequentially added to or deleted from the network, in the order that the reconfiguration designating data was described in the reconfiguration directory; and the cancel of the reconfiguration of the network configuration definition information to be executed in response to the cancel command is executed in the reverse order of having described the reconfiguration designating data in the reconfiguration directory.

If the reconfiguration command or the reconfiguration command designated by the cancel command contains the reconfiguration designating data related to a source to be connected to the CCP, the host computer gives to the CCP "a control command for reconfiguring the network configuration definition information of the CCP in accordance with the reconfiguration designating data; and in responsive to the control command the CCP reconfigures the network configuration definition information of the CCP.

According to one aspect of the present invention, the network reconfiguration information processing method, further comprises the steps of:

causing the host computer to store the reconfiguration command in a reconfiguration history file; and

after executing the cancel command, causing the host computer to delete the reconfiguration command corresponding to the reconfiguration directory designated by the cancel command, from the reconfiguration history file.

The network configuration definition information of the host computer includes original network configuration definition information and current network configuration definition information obtained by reconfiguring the original network configuration definition information, and when the operation of the host computer restarts upon loading a program, the host computer sequentially reconfigures the original network configuration definition information in accordance with the reconfiguration command read from the reconfiguration history file to generate the current network configuration definition information.

According to another aspect of the present invention, there is provided a method of processing reconfiguration information for a network having network configuration definition information, the network including a plurality of host computers one of which operates as a master and the others operate as slaves, at least one communication control processor (hereinafter called CCP) commonly connected to the host computers, and a plurality of resources connected to the CCP, the network reconfiguration information processing method comprises the steps of:

arranging a reconfiguration directory to each of the host computers, the reconfiguration directory including at least one reconfiguration designating data for defining a relation between the network and a resource to be deleted from or added to the network;

designating the reconfiguration directory and giving a reconfiguration command for reconfiguring the network configuration definition information, to each of the host computers;

responsive to the reconfiguration command, causing each of the host computers to reconfigure the network configuration definition information of each of the host computers in accordance with the defined reconfiguration designating data within the reconfiguration directory designated by the reconfiguration command, and store the designated reconfiguration directory in a directory file; and

if the reconfiguration directory designated by the reconfiguration command contains the reconfiguration designating data related to a resource to be connected to the CCP, causing the master host computer to give to the CCP a control command for reconfiguring the network configuration definition information of the CCP in accordance with the reconfiguration designating data, to thereby reconfigure the network configuration definition information of the CCP in response to the control command.

If the reconfiguration of the configuration definition information already executed by the reconfiguration command is to be canceled, this cancel is executed by the following steps:

designating one of the reconfiguration directories stored in the directory file, and giving to one of the host computers a cancel command for canceling the already executed reconfiguration of the network configuration definition information;

responsive to the cancel command, causing each of the host computers to cancel the reconfiguration of the network configuration definition information of each of the host computers already executed in accordance with the defined reconfiguration designating data within the designated reconfiguration directory, restore the network configuration definition information before the reconfiguration, and delete the designated reconfiguration directory from the directory file; and

if the reconfiguration directory designated by the cancel command contains the reconfiguration designating data related to a resource to be connected to the CCP, causing the master host computer to give to the CCP a control command for canceling a part of the reconfiguration of the network configuration definition information of the CCP in accordance with the reconfiguration designating data, to thereby cancel the reconfiguration of the network configuration definition information of the CCP in response to the control command.

According to still another aspect of the present invention, there is provided a method of processing reconfiguration information for a network having network configuration definition information, the network including a plurality of host computers one of which operates as a master and the others operate as slaves, at least one communication control processor (hereinafter called CCP) commonly connected to the host computers, and a plurality of resources connected to the CCP, the network reconfiguration information processing method comprises the steps of:

designating one of reconfiguration directories and inputting to one of the host computers a command for reconfiguring the network configuration definition information of the one host computer, the reconfiguration directory including a reconfiguration designating data related to at least one resource to be added to or deleted from the network;

causing the one host computer to reconfigure the network configuration definition information of the one host computer in accordance with the kind of the inputted command and the contents of the reconfiguration directory;

if the one host computer is a master and if the reconfiguration directory contains the reconfiguration designating data related to a resource to be connected to the CCP, causing the master host computer to give to the CCP a control command for "reconfigure the network configuration definition information of the CCP in accordance with the kind of the inputted command and the contents of the reconfiguration designating data, the control command including a reconfiguration sequence number in correspondence with the reconfiguration directory, and an indicator for indicating if the reconfiguration directory is the last one to be executed by the CCP;

updating first status information stored correspondence with the reconfiguration sequence number in accordance with whether or not the CCP executed the control command from the master host computer has successfully reconfigured the network configuration definition information, and transmitting a response message to the control command to the master host computer, the response message including information representative of whether or not the network configuration definition information has been executed successfully; and

causing the master host computer to update second status information stored in correspondence with the reconfiguration sequence number in accordance with the contents of the response message received from the CCP.

By storing status information in CCP and the master host computer, it becomes possible, for example, to identify the reconfiguration directory to be executed again for the reconfiguration, by causing, in response to a request from the master host computer after the operation of the master host computer restarts, the CCP to inform the master host computer of all reconfiguration numbers stored in the CCP and the first status information, by causing the master host computer to compare the reconfiguration sequence numbers and the first status information received from the CCP with reconfiguration sequence numbers and the second status information stored in the host computer, and by using the comparison result. If the comparison result indicates a presence of inconsistency between the reconfiguration sequence numbers, the reconfiguration is executed as to the reconfiguration commands after this sequence number.

The foregoing and other objects, advantages, manner of operation and novel features of the present invention will be understood from the following detailed description when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram used for explaining a dynamic network reconfiguration method according to the present invention;

FIG. 2 is a diagram showing the fundamental configuration of a computer network system embodying the present invention;

FIG. 3 shows the hardware structure of a host computer;

FIG. 4 shows the hardware structure of a CCP;

FIG. 5 is a diagram used for explaining a method of forming a load module and a reconfiguration directory;

FIG. 6 shows an example of network configuration definition for the network configuration shown in FIG. 1;

FIG. 7 shows a table group for HOST 1 generated from the network definition shown in FIG. 6;

FIG. 8 shows a table group for HOST 2 generated from the network definition shown in FIG. 6;

FIG. 9 shows a table group for CCP generated from the network definition shown in FIG. 6;

FIG. 10 shows a reconfiguration directory for HOST 1 generated from the reconfiguration definition shown in FIG. 1;

FIG. 11 shows a reconfiguration directory for HOST 2 generated from the reconfiguration definition shown in FIG. 1;

FIGS. 12A and 12B are flow charts illustrating the procedure to be executed by a host computer in response to a CHANGE command;

FIG. 13 shows the formats of a reconfiguration request message M1 for resource addition sent from a host computer to CCP, and a response message M2 from CCP;

FIG. 14 shows the formats of a reconfiguration request message M3 for resource deletion sent from a host computer to CCP, and a response message M4 from CCP;

FIG. 15 is a flow chart illustrating a procedure to be executed by CCP upon reception of a resource reconstruction request;

FIG. 16 shows a table group for HOST 1 generated upon input of a reconfiguration command;

FIG. 17 shows a table group for HOST 2 generated upon input of a reconfiguration command;

FIG. 18 shows a table group for CCP generated upon input of a reconfiguration command;

FIGS. 19A to 19C are flow charts illustrating the procedure to be executed by a host computer in response to a CANCEL command;

FIG. 20 is a flow chart illustrating an automatic reconfiguration procedure executed at the time of restarting the operation of a host computer;

FIGS. 21A to 21C are flow charts illustrating an automatic reconfiguration procedure to be executed by a master host computer in response to a START command at the time of restarting the operation of CCP;

FIG. 22 is a flow chart illustrating a procedure to be executed by a host computer in response to a CHANGE command;

FIG. 23 shows the structure of a reconfiguration processing management table;

FIG. 24A shows the format of a message M5 transmitted from a host computer to CCP for checking the integrity of reconfiguration information between a host computer and CCP;

FIG. 24B shows the format of a message M6 sent back from CCP in response to the message M5;

FIG. 25 is a flow chart illustrating another embodiment of the procedure to be executed by CCP in response to a reconfiguration request from a host computer;

FIG. 26 is a flow chart illustrating another embodiment of the procedure to be executed by a host computer in response to a CANCEL command;

FIG. 27 is a flow chart illustrating another embodiment of the control procedure to be executed by CCP in response to a CANCEL command entered from a host computer;

FIG. 28 is a flow chart illustrating another embodiment of the control procedure to be executed by a host computer in response to a START command;

FIG. 29 is a diagram showing a change in reconfiguration sequence numbers and processing status indicators when CHANGE commands are executed;

FIG. 30 is a diagram showing a change in reconfiguration sequence numbers and processing status indicators when the reconfiguration process is again executed for the reconfiguration directory "CH02" shown in FIG. 29 which was once canceled by a CANCEL command;

FIG. 31 is a diagram illustrating the procedure wherein after the directory "CH02" shown in FIG. 29 has failed its reconfiguration process, CCP is restarted using a START command;

FIG. 32 illustrates switching to a new master host computer upon occurrence of a channel trouble;

FIG. 33 is a diagram used for explaining the operation when reconfiguration information becomes inconsistent between a master host computer and CCP; and

FIG. 34 is a diagram showing another computer network system arrangement applicable to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 2 shows the system configuration according to an embodiment of the present invention. Reference numerals 1-l to 1-n represent host computers, one of which (e.g., 1-l) operates as a master and the others operate as slaves. Each host computer executes an execution image program loaded therein, the program containing network configuration definition information of the resources to be managed or controlled by the host computer. Reference numeral 2 represents a communication control processor (CCP) which executes an execution image program loaded therein, the program containing network configuration definition information of the resources to be controlled by CCP. Host computers and CCP are linked together by channels 3-l to 3-n for message transfer therebetween. Messages are transferred between CCP and other processors 9-l to 9-n via a plurality of communication paths 8-l to 8-n.

FIG. 3 shows the hardware structure of a host computer 1. An instruction processor (IP) 11 executes a program for processing data communications, business transactions, or the like. A main storage (MS) 12 stores programs, tables, and transmission/reception data. An operator console 13 is used for entering an operator command to a service processor (SVP) 14 and. for outputting a message to an operator. A load module file 4 stores execution image programs containing network definition information of the resources to be managed or controlled by the host computer. This program is loaded in MS 12 when it is executed. A load module file 5 stores execution image programs containing network definition information of the resources to be controlled by CCP. This program is transferred to CCP and executed by CCP. A directory file 6 stores definition information representative of the reconfiguration of the original network definition information, in the form of the execution image format (table format). This reconfiguration information is reflected to host computers or to a program running on CCP, in a manner to be described later.

Information offline recorded on such as a magnetic tape 10 in a manner to be described later is loaded in each of the load module files 4 and 5, and the directory file 6. A history information file 7 stores the name of a reconfiguration directory file executed by a reconfiguration command to be described later. This history information file 7 is used to automatically reflect definition information representative of the reconfiguration of the original network definition information, when a host computer or CCP restarts. I/O control processors (IOP) 15-1 and 15-2 are connected to CCP 2 or files 4 to 7 and 10 via channels 3 for data transfer therebetween.

FIG. 4 shows the hardware structure of CCP 2. An instruction processor (IP) 16 executes a CCP program for processing data communications. A main storage (MS) 17 stores programs, tables, and transmission/reception data. Channel adaptors 18-l to 18-n connectable to host computers via channels 3-l to 3-n control the data transfer to and from host computers. Communication scanners (CS) 19-l to 19-n control scanning a plurality of lines and transmitting/receiving data to and from the lines.

In this embodiment, the start operation such as CCP program loading is assumed to be allowed only by a master host computer. The attributes (master/slave) of host computers are designated, for example, by network configuration definition information at the time of system configuration. When a host computer having a master attributes is in trouble, a host computer having had a slave attribute is changed to a new host computer having a master attribute by entering an OWN command from the operator console of this host computer.

FIG. 5 shows an example of a method of forming an execution image program.

Network configuration definition 22 represents the configuration information of the whole network to be managed, the information being described in conformity with predetermined syntax rules. A set of configuration definitions is prepared for the whole network system to be managed. Procedure 21 is a module group used for executing a program. Definition utility 20 is operated offline to take out network definition information of the resources to be managed or controlled by each host computer or CCP. The taken-out information is converted into a table format, to form an execution image program by linking a necessary procedure to the taken-out information. These programs constitute host computer load modules 24-l to 24-n and a CCP load module 25.

Each of the host computer load modules 24-l to 24-n is stored in the load module file 4 (FIG. 2) of the corresponding host computer. The CCP load module 25 is stored in the CCP load module files 5 (FIG. 2) of all host computers connected to CCP. This is because any one of host computers connected to CCP which becomes a master is allowed to start operating upon loading a program to CCP. The host computer load module and CCP load module are formed offline, for example, by one host computer, and inputted to the files of other host computers.

For example, in a network system shown in FIG. 1, two host computers (HOST 1, HOST 2) 1-1 and 1-2 are connected to CCP 2. HOST 2 is connected to a local terminal (terminal LOCAL 2 directly connected to HOST 2) 29-2, and CCP 2 is connected via a line (LINE) 30 to a terminal control equipment (TCE 1), and to a video terminal (VDT 1) 32-1 and a printer (PRT 1) 33. An application program (TSS) 34 runs on HOST 1, and another application program (DCCM) 35 runs on HOST 2.

FIG. 6 shows an example of the configuration definition 22 corresponding to the network shown in FIG. 1. The network configuration definition 22 is constituted by hos