An APPN node by default provides some level of resource
registration within the network node or end node, depending on its
resource type. However, the level of registration can be specified
on local resource definitions with the REGISTER operand.
Because VTAM® application
programs are likely to generate more LU-LU session traffic than other
resources, and therefore more APPN locate searches, application programs
should be registered on their network node server and optionally on
the central directory server to reduce traffic. However, in certain
cases, an application program should not be dynamically defined to
the APPN network. Such application programs include:
- Programs without network-unique names, such as those that have
been excluded from participating in cross-domain session setup
- Programs that participate only in LU-LU sessions within the local VTAM domain
- Programs that can participate in cross-domain LU-LU sessions but
will never be the target of a cross-domain search request.
An example of an application program that should not be
defined dynamically is TSO/VTAM. TSO usually runs on a host as several
applications programs. One main task handles cross-domain LU-LU session
setup, and several subtasks control LU-LU sessions after session setup
so that TSO services can be accessed by users. See "Resource Registration in an APPN Network" in
the z/OS Communications Server: SNA Network Implementation
Guide for information about how TSO/VTAM
applications are registered.