In general, you should not be concerned with the buffer space required for an individual message. However, you must ensure that the message buffer space is large enough to hold a message of the length specified (on the CLASSLEN keyword) for the transport class.

However, when the message traffic in your sysplex requires you to limit the number of message buffers, you do need to know how much buffer space is required to support a particular message length. For detailed information on this topic, see Calculating message buffer space — An example.

When you define a list structure for signaling, more than one signaling path might be started. Therefore, to compute the message buffer space required by the system, you must anticipate the maximum number of signaling paths that might be started through the list structure.