A VTAM® attached through an external communication adapter (XCA), such as an IBM® 3172 Nways Interconnect Controller or an IBM Open Systems Adapter, can communicate to other SNA domains through an Ethernet or Ethernet-type local area network (LAN), token ring, or FDDI LAN. You define an XCA LAN connection to VTAM using the external communication adapter (XCA) major node.

For each LAN connected through an XCA, code a VBUILD TYPE=XCA definition statement. The PORT statement identifies the connection between VTAM and the LAN, so you can code only one PORT definition statement for each major node.

A VTAM attached to a LAN through an XCA is defined to its peer processor by the LINE and PU definition statements. These statements must be coded as a nonswitched group using the GROUP definition statement.

If you have multiple VTAM hosts on a local area network attached through one XCA, you can specify which host to contact by using the service access point address (SAPADDR operand) and medium access control address (MACADDR operand) to specify the host. Each host should have a different combination of the SAPADDR operand and MACADDR operand.