Defining a multiple-network environment

Defining your multiple-network environment involves identifying your different networks and defining the resources that will help you communicate between the networks. You need the following for controlling cross-network sessions:

Gateway VTAMs: Enable at least one gateway VTAM® for each network gateway. The gateway VTAM controls sessions across the network gateway. The gateway VTAM is in session with the gateway NCP, assisting in address translation and cross-network routing. The gateway VTAM must be either an MVS™ host running VTAM Version 2 Release 2 or higher releases or a VM host running VTAM Version 3 Release 1.1 or higher releases.
Gateway NCPs: You must specify at least one gateway NCP for each network gateway. The gateway NCP works with the gateway VTAM to control address translation for cross-network sessions. The gateway NCP provides network address translation from a pool of network alias addresses for each network. The gateway NCP also assists in activating explicit and virtual routes for cross-network sessions.
The gateway NCP is a resource in each network to which it connects. Each gateway NCP has one native network, where the gateway VTAM that can activate the NCP subordinate resources resides. Each gateway NCP also has one or more nonnative networks. For example, in Figure 1, NCP21 is subarea 21 in NETA and subarea 51 in NETX. NCP21 native network is NETA; its nonnative network is NETX.

The configuration in Figure 1 is the same as the configuration in Figure 1, except that Figure 1 shows a multiple-network environment because it contains two independent SNA networks. NCP21 in NETA is also subarea 51 in NETX and NCP11 in NETB is also subarea 52 in NETX. There are two NCP11s in this environment. The names can be the same because they reside in different networks (hosts, however, cannot have the same name because of CDRM conflicts).

Code everything that you would for Figure 1. NETID must be coded in the start options to the definition of HOST1 in NETA:

Add at least the following to the definition of HOST2 in NETA:

GWSSCP=YES must be defaulted or coded and NETID should be coded in the start options.
One NETWORK definition statement for each CDRM or group of CDRMs, identifying which CDRMs reside in each network.
CDRM definition statement in the cross-domain resource manager major node for VTAM3 in NETB.
A GWPATH definition statement following the cross-domain resource manager minor node for VTAM3 in NETB. Code the ADJNET, ADJNETEL, ADJSA, and GWN or SA operands.
NETID and GWCTL operands on the PCCU definition statement defining NCP21 in NETA.
NETID, HSBPOOL, and CANETID operands on the BUILD definition statement in the NCP major node for NCP21 in NETA.
GWNAU definition statement in the NCP major node to identify subarea 52 in NETX.
NETWORK definition statement in the NCP major node to identify NETX. Code the NUMHSAS and SUBAREA operands.
GWNAU definition statement to represent NCP21 in NETA as NCP51 in NETX.
Figure 1. Multiple-network environment

Also code at least the following in HOST3 in NETB:

Start options for HOST3 in NETB (NETID, SSCPID, and SSCPNAME); code or default to GWSSCP=YES.
Application program minor node for APPL1 in NETB.
One NCP major node for NCP11 in NETB.
One NETWORK definition statement for each CDRM or group of CDRMs, identifying which CDRMs reside in each network.
CDRM definition statements in the cross-domain resource manager major node for VTAM3 in NETB and VTAM2 in NETA.
A GWPATH definition statement following the cross-domain resource manager minor node for VTAM2 in NETA. Code the ADJNET, ADJNETEL, ADJSA, and GWN or SA operands.
NETID and GWCTL operands on the PCCU definition statement defining NCP11 in NETB.
NETID, HSBPOOL, and CANETID operands on the BUILD statement in the NCP major node for NCP11 in NETB.
GWNAU definition statement in the NCP major node to identify NCP51 in NETX.
NETWORK definition statement in the NCP major node to identify NETX. Code the NUMHSAS and SUBAREA operands.
GWNAU definition statement to represent NCP11 in NETB as NCP52 in NETX.

Note: Resources with identical names can exist in interconnected networks. To resolve naming conflicts, use the NetView® alias name translation facility or the NQNMODE=NQNAME start option. For information about the NetView alias name translation facility, see NetView alias name translation facility. For information about the NQNMODE=NQNAME start option, see the z/OS Communications Server: SNA Resource Definition Reference.

SNA network interconnection provides the following major functions:

Cross-network session control: Enables VTAM to perform cross-network session initiation and termination. As required, VTAM can request address translation, name translation, and configuration data.
Address translation: Enables networks with different addressing schemes to communicate. The gateway NCP performs the function of address translation when crossing network boundaries.
Resource name translation: Enables networks with conflicting resource names to communicate. This function can be performed by the NetView program or the VTAM session management exit routine.
Note: The NQNMODE=NQNAME start option is an alternative to resource name translation. For more information, see the z/OS Communications Server: SNA Resource Definition Reference.
Cross-network problem determination and network management: Collects and correlates problem determination and network configuration information for cross-network sessions. The NetView program provides the function of cross-network problem determination and network management.