Timing considerations
Timing considerations during startup can affect network communications.
IBM® i has the capability to automatically start the necessary subsystems, TCP/IP, lines, interfaces, and servers at the appropriate times during IPL. In most situations, your network communications will start smoothly using this automatic startup process.
- The processing speed and the number of input-output processors (IOPs) can affect the startup of the network hardware resource. If your hardware resource is slow to start, it might not be ready when TCP/IP tries to start. Your network communications fail because the TCP/IP interfaces cannot be started.
- You might encounter timing problems if you have customized your server so that you are using subsystems other than the IBM-supplied subsystems. Many subsystems are typically started by the IPL startup program. However, if you are using customized subsystems that are not recognized by the IPL startup program, they will not be automatically started at IPL. Your network communications fail because these subsystems have not been started.
If these types of timing problems occur, you can automatically start the subsystems, TCP/IP, interfaces, and servers in the correct order by creating a customized IPL startup program. You might need to put delays in the startup program to ensure that each step of the startup process is initiated at the appropriate time. For example, the subsystems should be started before TCP/IP, and the interfaces should be started after the communications resources are available.
To change from using the default IPL startup program to using a customized startup program, follow these steps: