Supplying control vectors with the SETLOGON START

If VTAM® indicates (by the ISTAMSVL DSECT) that it supports applications supplying user vectors on the SETLOGON START and if the application turns on VAC81UCV when it issues its OPEN ACB, the application can provide a TCP/IP Information Control Vector (CV64) when it issues the SETLOGON OPTCD=START macroinstruction. The CV64 contains IP address and port information, as well as other IP characteristics. After this information is associated with the application, it can be propagated to the PLU of a session with this application and some of it can be displayed by a VTAM operator, depending on the settings of the IPINFO start option.

To pass the CV64, the application needs to turn on RPLNIB and set RPLARG in the SETLOGON RPL to point to a NIB and the application needs to set NIBUCVA in that NIB to point to a vector list. The format of vector list is shown in Figure 1.

Figure 1. Format of the CV64 Vector List to supply with SETLOGON START
The diagram shows the format of the CV64 vector list to supply with SETLOGON START. The CV64 vector list has three fields. The first field indicates the total length including this field itself. The second field is the vector ID (X'64'). The third field contains vector length and vector data.

The lengths and the subvectors of the CV64 will be checked. If all is fine, the CV64 will be stored and associated with the SETLOGON issuer for later use in a session setup or a display.

If the application issues another SETLOGON START with CV64 information, the old CV64 information stored by VTAM will be deleted and it will be replaced with the new CV64.

If the application attempts to pass the CV64 on the SETLOGON START without having indicated that it will exploit the new function, the CV64 information will be ignored. Likewise, if the application attempts to pass the CV64 on the SETLOGON START to a VTAM that does not support the function, the CV64 information will be ignored.