All buffer pool values that you specify override the previously specified values, while buffer pools that you do not code default to the IBM-supplied values.
In the following example, LPBUF values are specified in the default start option list. When VTAM® is started, the system operator selects start option list ST, which contains new LPBUF values which will override the previous values. VTAM processes these values in the order shown below. For more details about processing, see z/OS Communications Server: SNA Network Implementation Guide.