The following three start options are required:

SSCPID

The SSCPID start option provides VTAM® with a unique numeric identifier. The SSCPID value is used by some physical units to identify the VTAM with which it is in session.

If you plan to expand or incorporate a single-domain network into a larger network, be sure that the value of SSCPID is unique for each host. The SSCPID value you specify must be different from the SSCPIDs in other networks that can be in session with this host.

If you plan to incorporate a non-VTAM host, the values of the VTAM SSCPID and HOSTSA start options should be coded so that one of the following items is true:

• The values for both SSCPID and HOSTSA are higher than the non-VTAM host.
• The values for both SSCPID and HOSTSA are lower than the non-VTAM host.

When activating the cross-domain resource manager-cross-domain resource manager (CDRM-CDRM) session, the host with the higher SSCPID value sends the activate cross-domain resource manager (ACTCDRM) and the host with the higher HOSTSA value activates the route. Unpredictable results occur if the route chosen for the ACTCDRM is different from the route activated.

SSCPNAME

The SSCPNAME start option provides a unique name for VTAM. This option is required for a single-domain network, but is primarily used in multiple-domain and multiple-network environments to identify a particular VTAM. The SSCPNAME option must be different from the HOSTPU start option that identifies the physical unit within VTAM.

The SSCPNAME option is also used as the CP name for a VTAM that implements APPN. Although the SSCPNAME and CP name are identical, note that the SSCP and CP are distinct resources and can be displayed individually.

Note: The SSCPNAME should match the name that is coded in the CDRM major node for this VTAM.

NETID

The NETID start option provides VTAM with the network identifier. If you connect your VTAM to another network, the network identifiers must be unique. The network name should conform to an overall naming standard, such as:

• The first two characters identify the country in which the network is managed and comply with the International Standards Organization (ISO) Standard 3166.
• The next four characters identify your enterprise.
• The last two characters identify a particular network within your enterprise.

For example, an IBM® network within the United States could have the network identifier USIBMCMK, where US identifies the country, IBMC identifies the enterprise, and MK identifies a particular network within IBM.

Notes:

1. Using the # symbol for defining network identifiers (NETIDs) is not recommended.
2. To assist SNA network owners in controlling the uniqueness of their network IDs, IBM has established a worldwide SNA Network Registry. Registering a network ID in the SNA Network Registry confirms its uniqueness from all other network IDs within the registry, thus minimizing future connectivity problems. To register a network ID, contact your IBM branch office representative.