Defining a gateway VTAM

The gateway VTAM®, in conjunction with the gateway NCP, performs cross-network session initiation and termination by acting as an intermediary between VTAMs in the connected networks. (After the session is set up, there is no need for the LU-LU session path to go through the gateway VTAM.) The gateway VTAM also directs the gateway NCP to set up the address transformations and routes needed for cross-network sessions. The gateway VTAM determines the routing for cross-network sessions and resolves resource names in conjunction with the name translation facility.

Note: A gateway VTAM must be either an MVS™ host with VTAM Version 2 Release 2 or higher, or a VM host with VTAM Version 3 Release 1.1 or higher.

The gateway VTAM can be in any one of the connected networks.

To convert a non-SNI VTAM to a gateway VTAM, you need to make the following changes:

Update your start options.
Update your initial configuration list.
Update your application program major node if you are using NetView® alias name translation facility.
Update your CDRM major node.
Create CDRSC definition statements (optional).
Create an adjacent SSCP table.

In a gateway configuration, VTAM has several different names. The following three names are assigned using start options:

The ID specified on the SSCPID start option
The name specified on the SSCPNAME start option
The name specified on the HOSTPU start option

These are the names by which this SSCP CDRM is known by other domains in this and other networks. No requirement exists for these names to match any of the other names listed previously. However, you might want to have each CDRM known by a single name throughout all the networks. You can do this by coding a single set of CDRM definitions that is used in all the connected networks. Coding the same name for this SSCP on all definitions makes network management easier.

Another name can be assigned on the CDRM definition statement. However, if that name differs from the SSCPNAME that is used, the results are unpredictable because of VTAM unique use of each of the varying names. It is recommended that these names be the same to avoid inconsistencies. One exception to this is that HOSTPU must be different from the CDRM name or SSCPNAME.