OpenTP1 Version 7 System Definition

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dcbindht (Specify host name for OpenTP1 communication or for using system switchover facility)

Format

{{dcbindht -h host-name [-n network-name[,network-name]...]}}

Function

This command specifies which network adapter OpenTP1 uses to communicate if the host running OpenTP1 is connected to multiple network adapters. If multiple IP addresses can be assigned to a single network adapter, you specify which IP address OpenTP1 uses for communication. You also need to specify an IP address when the host performs system switchover by inheriting the IP address.

This command explicitly notifies the communication destination OpenTP1 that the source OpenTP1 is running using the IP address corresponding to the host name specified in the dcbindht command.

If the machine is connected to only one network adapter and has only one IP address, the IP address used by OpenTP1 is physically fixed to one. In that case, you do not need to specify this command.

Specify this command if multiple OpenTP1 systems operate at one host in the system switchover that inherits the IP address like a 2-to-1 switchover organization or mutual switchover organization. If a connection is made between the networks over the router, specify all networks that communicate via the network adapter specified here.

If you do not specify this command, TCP/IP determines the network adapter or IP address to be used for access. Note that if you do not specify this command even if multiple IP addresses or multiple network adapters are used, an undesired IP address may be reported to the communication destination OpenTP1 and a communication error might occur.

As shown below, OpenTP1 uses the IP address corresponding to the specified host name for all communications if you do not specify a network name in this definition. You cannot specify this command more than once without a specified network name in the definition. If you specify this command more than once, the first command takes precedence, and subsequent commands are ignored. If a command specified with a network name and a command without a network name both exist, the command specified with a network name takes precedence.

System common definition

dcbindht -h HOST_A -n NET_A,NET_B    # If the send destination
                                     network addresses are
                                     # NET_A and NET_B, host name
                                     HOST_A is bound and sent.
dcbindht -h HOST_B                   # If the send destination
                                     network address is other than
                                     # NET_A and NET_B, host name
                                     HOST_B is bound and sent.
dcbindht -h HOST_C                   # Even if this definition
                                     is made, host name HOST_B,
                                     # which is defined before,
                                     is validated.

When you use this specification in a network environment having a subnet, you also need to specify the rpc_netmask operand in the set format definition, which is a system common definition.

If you do not specify the rpc_netmask operand when OpenTP1 is running in a network having a subnet, the specification in the dcbindht command has no effect. This is because the network name specified in the dcbindht command format definition does not match any network address that OpenTP1 recognizes. Note that all the networks belonging to the OpenTP1 global domain must use the same subnet mask specified in the rpc_netmask operand.

Option

-h host-name~<1-255 character identifier>

Specify the applicable host name or the host name of the network adapter which is used for the OpenTP1 communication. When more than one IP address can be assigned to one network adapter and to perform switchover by inheriting the IP address, specify the host name for the IP address that you want to inherit. The identifier you specify can consist of alphanumeric characters, periods, and hyphens. You cannot specify the identifier in an IP address format. The host name must be mapped with an IP address in the /etc/hosts file or by using DNS. If you specify localhost or a host whose IP address begins with 127 (example: 127.0.0.1) in host-name, a communication error might occur.

Note that when you use dc_rpc_call_to(), if the host name specified in this option differs from the host name specified in the my_host operand, the operation is not guaranteed.

-n network-name~<1-64 character identifier>

Specify the name of the network to communicate with via a network adapter or an IP address specified in the -h option. The network name must be mapped with a network number in the /etc/networks file or by using NIS.

You can omit this option. If you omit this option, OpenTP1 uses the network adapter or the IP address corresponding to the host name specified in the -h option for all communications.

Note

With the configuration shown in Figure 3-1, IP address ip=a or ip=x is used to communicate from OpenTP1 B to OpenTP1 A.

When the OpenTP1 system accepts a service request, it stores the IP address used to collect the service address information.

If a system switchover occurs after collecting the address information using IP address ip=x, ip=x is inherited from OpenTP1 X to OpenTP1 X'. OpenTP1 B remains storing the IP address as ip=x when collecting the address information. When a service request is sent in this state, the service request which should have been sent to OpenTP1 A may be sent OpenTP1 X'. (Figure 3-2.)

To communicate to the target OpenTP1 system, specify a network adapter which is used for communications by defining the following:

If the dcbindht command definition is specified, IP address ip=a is used to communicate to OpenTP1 A while the IP address ip=x is used to communicate to OpenTP1 X.

Figure 3-2 Communication after system switchover

[Figure]