The transport providers are specified with the SUBFILESYSTYPE statements
in BPXPRMxx or specified with the SETOMVS command. The default transport
provider is one of the following:
- The transport provider specified as the default on the SUBFILESYSTYPE
statement in BPXPRMxx.
- If DEFAULT was not specified, the transport provider from the
first SUBFILESYSTYPE statement will become the default transport provider
while it is active.
- If DEFAULT was not specified, the first SUBFILESYSTYPE transport
provider specified is not active, and no other stacks are active,
then the first transport provider activated becomes the default. The
selection of default transport providers can become unpredictable
if stacks are stopped and restarted while the specified default transport
provider and the first SUBFILESYSTYPE transport provider are inactive.