Configuring a IBM Connect:Direct/Plex Environment
IBM® Connect:Direct® runs in two configurations:
- IBM Connect:Direct Stand-alone Server, which is a single IBM Connect:Direct system operating within an IBM z/OS environment.
- IBM Connect:Direct/Plex, which is a IBM Connect:Direct system operating in an IBM z/OS sysplex or parallel sysplex environment consisting of a IBM Connect:Direct Manager and one or more IBM Connect:Direct Servers.
Differences Between Stand-Alone and Plex Environments
A IBM Connect:Direct Stand-alone Server and a IBM Connect:Direct/Plex environment have the following configuration differences:
- Initialization parameters
The two sets of initialization parameters in IBM Connect:Direct are global and local.
A IBM Connect:Direct Stand-alone Server uses only global initialization parameters to set system-wide values, as shown in the following illustration.
A IBM Connect:Direct/Plex environment uses both global and local initialization parameters. Global initialization parameters apply to each member of the IBM Connect:Direct/Plex environment. Local initialization parameters apply to specific members of the IBM Connect:Direct/Plex environment and can override some global initialization parameters affecting that member. Each IBM Connect:Direct/Plex member must have its own local initialization parameter member with the parameter, CDPLEX.MANAGER = NO | YES, as the first statement in the member.
If an update of the global and local initialization parameter files is performed using Control Center and fails during the process, IBM Connect:Direct will use the backup members to restore the parameters. IBM Connect:Direct will never use the backup members to initialize the DTF unless you explictily instruct the system to do so by updating the JCL to use the backup members as the initparm members.
Global initialization parameters are stored in a file shared by all IBM Connect:Direct/Plex members. In the EXEC statement (IBM Connect:Direct Stand-alone Server and IBM Connect:Direct/Plex), the PARM= keyword specifies the name and location of the global initialization parameters file.
The local initialization parameters of each IBM Connect:Direct/Plex member are stored in a unique PDS member for each system (one for the Plex Manager and one for each server). The location of the local initialization parameters file is specified by the //CDPLEX DD in the startup JCL of each member.
In a IBM Connect:Direct/Plex environment, you can override only the initialization parameters allowed in the local initialization parameters member by using the PARM= keyword in the EXEC statement at system startup.
In a IBM Connect:Direct Stand-alone Server environment, however, you can override global initialization parameters with the PARM= keyword in the EXEC statement.
The following illustration shows how global and local initialization parameters are used in a IBM Connect:Direct/Plex environment.

- VTAM APPLIDs
A IBM Connect:Direct Stand-alone Server obtains its VTAM APPLIDs from the network map.
In a IBM Connect:Direct/Plex environment, the IBM Connect:Direct/Manager obtains its VTAM APPLIDs from the network map, but each IBM Connect:Direct Server obtains its VTAM APPLIDs from its local initialization parameters file.
- TCP/IP addresses and ports
A IBM Connect:Direct Stand-alone Server obtains its TCP/IP listen ports from the global initialization parameters file.
In a IBM Connect:Direct/Plex environment, the IBM Connect:Direct Manager and IBM Connect:Direct Servers obtain their TCP/IP addresses and listen port numbers from their local initialization parameters members. However, if the TCP port number is not specified in the local initialization parameters member of the IBM Connect:Direct Manager, the IBM Connect:Direct Manager obtains its listen port number from the global initialization parameters member.
Each server overrides the global initialization parameters by specifying those parameters in that server's local initialization parameters. The first address defined in the parameter becomes the local or default address. For more information about defining TCP/IP listening tasks, see TCP/IP Port Number.
The CDPLEX.REDIRECT local initialization parameter is used by the IBM Connect:Direct/Plex Manager in the IBM Connect:Direct/Plex environment to determine the redirection address that is presented to the remote node. This parameter allows you to specify redirection addresses based on the security node type (internal or external) and session type (TCP/IP) of the adjacent node in the network map.
When an address is specified, an internal address and external address is defined and each can have a specified redirection port defined. When the adjacent node entry is defined with the INT flag, the appropriate internal address is returned. Conversely, when the EXT flag is defined, the appropriate external address is returned.Note: If your environment requires additional external redirection addresses to enable a remote IBM Connect:Direct server to run Processes, see the local initialization parameter, CDPLEX.REDIRECT.EXCEPTION = ((Mgr-IP, Ext_Svr-IP, Ext_Svr-port, Exception-IP, Exception-port),...).Up to eight different addresses or ports can be defined for each server. However, in the IBM Connect:Direct/Plex server that defines CDPLEX.REDIRECT only two are effectively used when Process redirection occurs. To use the additional port in the IBM Connect:Direct/Plex servers, those servers must be contacted directly by the remote node.Note: A special consideration exists if the IBM Connect:Direct/Plex Manager is initialized on a system that is not IPv6 enabled, and one or more of the servers supports IPv6. When the IBM Connect:Direct/Plex is the SNODE, the IBM Connect:Direct/Plex Manager accepts connection requests for IPv4 only. However, if the IBM Connect:Direct/Plex is the PNODE, the IBM Connect:Direct/Plex Manager can assign outbound processes to a IBM Connect:Direct Server that supports IPv6.
- System files
In a IBM Connect:Direct Stand-alone Server, the system files (network map, Statistics Pairs, CKPT, AUTH, Message, TCQ and TCX files) are stored in one location and apply to the entire DTF. If two IBM Connect:Direct Stand-alone Server systems operate in a sysplex environment, each system must have its own system files.
In a IBM Connect:Direct/Plex environment, the system files are also stored in one location and are shared by all IBM Connect:Direct/Plex members, as in the earlier illustration. Only one set of system files is needed for all IBM Connect:Direct/Plex members.