You might want to run multiple TCP/IP stacks on the same
system to provide network isolation for one or more of your applications.
For instance, you may have multiple Open System Adapter (OSA) features,
each one connecting your system to a different network. You can assign
a TCP/IP stack to each feature.
Before you begin
When configuring the product on a system with multiple stacks,
you must first establish the product's stack affinity to the desired
stack. Establishing stack affinity binds all socket communications
to that stack, and allocates the proper host name resolution configuration
data sets to the product. These data sets enable host name lookups
to have the desired results.
Use the NETWORK DOMAINNAME parameter
of SYS1.PARMLIB(BPXPRMxx) to specify the common INET physical file
system, C_INET PFS, and then use this file system to set up multiple
TCP/IP stacks. This physical file system allows you to configure multiple
physical file systems (network sockets) and make them active concurrently.
If
you plan to configure the product to use a non-default TCP/IP stack,
consult z/OS® UNIX System Services Planning,
and z/OS Communications Server: IP Configuration
Reference, for details.
About this task
Avoid trouble: In the following steps,
you will set a number variables. It is important to understand that
these variables should be set at the node level.
gotcha
To
configure the product on a system with multiple stacks:
Procedure
- Configure the data set for each application server's host
name resolution. In the administrative console, click.
- Add the RESOLVER_CONFIG UNIX process variable and specify
the data set name in the value field.
- Export the RESOLVER_CONFIG variable in client shell
scripts.
- You can also use JCL to specify the name resolution configuration
data set. To use JCL, add //SYSTCPD DD DSN=some.tcpip.DATA,DISP=SHR
to the server JCL. The RESOLVER_CONFIG variable overrides the SYSTCPD
DD statement.
See z/OS Communications Server: IP
Configuration Reference, for more information on the RESOLVER_CONFIG
variable.
- Establish the Application Server's stack affinity to the
desired stack.
- In the administrative console, click and
set the _BPXK_SETIBMOPT_TRANSPORT UNIX process variable to the value
of the desired transport. If this variable does not exist,
click New and add it.
- Export the _BPXK_SETIBMOPT_TRANSPORT variable in client
shell scripts.
To set the BPXK_SETIBMOPT_TRANSPORT variable in the
was.env file for the Daemon, you must prefix the variable with DAEMON_.
This additional information causes the transformer that generates
the was.env files to put add the variable to the was.env file for
the Daemon. Because the _BPXK_SETIBMOPT_TRANSPORT variable
already has a leading underscore, the final version of this variable,
when set for the Daemon, contains two underscores preceding the variable
name, as shown here DAEMON__BPXK_SETIBMOPT_TRANSPORT.
Avoid trouble: If you are setting this variable for
the Daemon, you probably want to set it at the cell level to give
all the Daemons in that cell the same setting. Unless one of the Daemons
is serving multiple nodes, if for some reason you need to specify
different settings for different Daemons in a cell, , you can set
this variable at the node level.
gotcha
See z/OS UNIX System
Services Planning, for more information on the _BPXK_SETIBMOPT_TRANSPORT
variable.