Chapter 9 Handling z/OS Connectivity Problems
Port Switching Printer Sharing

To support printer sharing, 10/100Base-T Ethernet Interface printers automatically switch among all attached ports (serial port, the twinax or coax port, or the Ethernet network port). Basically, the printer prints jobs for one port until no new jobs appear and the port “times out”. The printer then switches to the next port and does the same thing.

To change the default “time out” value for a port, update the

TIMEOUT value for the port on the appropriate menu (Serial

Interface, Ethernet, Twinax Interface, or Coax Interface).

Handling z/OS Connectivity Problems

If you encounter problems when “ping”-ing a network printer from z/OS, here is how to resolve them.

Ping is Not Successful

If the “ping” is not successful, verify the following:

•The printer is powered on.

•The IP address is unique in the TCP/IP network.

If the IP address of the z/OS system is not unique, see your network administrator to resolve the IP address problem.

•The Maximum Transmission Unit (MTU) size of the IP packet for the z/OS system is equal to the MTU size of the printer. For information about the values recommended for the z/OS system, see “Modify the TCP/IP Profile in z/OS” on page 214.

To change the MTU size for the z/OS system, change the GATEWAY statement in the z/OS TCP/IP profile, and restart TCP/IP to pick up the changes.

You cannot change the MTU size on a 10/100Base-T Ethernet Interface printer. The MTU size is fixed at 1024 bytes.

If these items are all in order, consult your TCP/IP network administrator about a possible network problem.

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