External communication adapter (XCA) connections

This section describes the local area networks (LANs) that can connect to VTAM® through an XCA. XCA can include an IBM® 3172 Nways Interconnect Controller or an IBM S/390® or zSeries Open Systems Adapter.

VTAM and an XCA support the following types of LANs:

Ethernet or Ethernet-type LAN
Token ring
Fiber Distributed Data Interface (FDDI)

This support allows SNA applications to access the supported LANs. TCP/IP and SNA applications can use the same physical attachment to an XCA at the same time.

VTAM connected through an XCA cannot load an NCP across a local area network.

Note: ATM networks accessed through LAN emulation appear to VTAM to be Ethernet or Ethernet-type LANs or token-ring networks and are defined to VTAM as such. ATM networks accessed through native ATM are defined to VTAM differently from those accessed through LAN emulation. See ATM native connections for information about defining ATM native connections.