Getting started with dynamic XCF

The minimum requirements for TCP/IP stacks to use dynamic XCF differ based on whether same host or inter-host communication is being used. To generate definitions for two TCP/IP stacks that reside on different MVS™ hosts:
  • Both MVS hosts must belong to the same sysplex.
  • VTAM® must have XCF communications enabled by specifying the XCFINIT=YES or XCFINIT=DEFINE start option, or by activating the VTAM XCF local SNA major node, ISTLSXCF. For details about configuration, see z/OS Communications Server: SNA Network Implementation Guide.
  • DYNAMICXCF must be specified in the TCP/IP profile of each stack.

With this configuration, both same host and inter-host communication can be performed using dynamic XCF.

To generate definitions for two TCP/IP stacks that are on the same MVS host, you must specify DYNAMICXCF in the TCP/IP profile of each stack.

At initialization, each TCP/IP stack configured for XCF joins a well-known XCF group. When other stacks in the group discover the new stack, the definitions are created automatically, the links are activated, and the remote IP address for each link is added to the routing table. After the remote IP address has been added, IP traffic proceeds as usual.

In VTAM, you must activate the XCF local SNA major node. You can do this using the start option XCFINIT=YES or XCFINIT=DEFINE. If dynamically defined XCF definitions have been created for another VTAM in the sysplex that has since stopped and restarted with a different CPName, dynamic XCF recognizes this situation and automatically modifies existing definitions to accommodate the CPName change. If the XCF local SNA major node is inactive when TCP/IP is started and is not activated until after TCP/IP has finished initialization, TCP/IP does not generate any dynamic definitions for other TCP/IP hosts already started in the sysplex until either:
  • A new TCP/IP host is detected
  • A profile related operator command is issued (such as the VARY TCPIP,,OBEYFILE, VARY TCPIP,,START, or VARY TCPIP,,STOP commands)
Parent topic: Dynamic XCF