Restrictions: System programmers and network designers should
be aware of the following information about the
CINET prerouting
function:
- Home IP addresses. Two or more transports running on z/OS that connect
to z/OS UNIX may
contain home IP addresses on the same network or subnetwork. However,
load balancing across transports is not done.
- Network destinations. Two or more transports may have
network destinations that are the same. Again, load balancing across
transports is not performed.
- Metrics for network routes. All routes are equal and their
metrics are compared.
If two or more transports maintain network
routes to the same destination network, metric information is needed
from each transport in order to correctly select the best route. For
IBM's TCP/IP, this is best accomplished when each TCP/IP is running
with a dynamic routing daemon (OMPROUTE). When two or more transports
maintain indirect routes to the network, statically defined indirect
routes (routes to destinations that do not reside on a transport's
directly attached links) do not provide adequate metric information
to select the shortest route to a destination network.
- If two or more transports contain network routes with no metric
information or duplicate metrics, then the default transport is called
to process the request. The default transport is either the file
system that specified DEFAULT on the SUBFILESYSTYPE statement (if
active), or it is the first transport that was activated.
- Host routes. Host-defined routes are always searched before
network routes.
- Severed connection to z/OS UNIX services.
If a transport should sever its connection with z/OS UNIX, all routing
information for the severed transport is deleted. If the severed
transport maintained duplicate home or network routes, these routes
are deleted. Subsequent requests for the duplicate routes are routed
to the remaining transports.