ATM networks accessed through native ATM are also attached to VTAM® through an IBM® Open Systems Adapter (configured in HPDT ATM native mode). They offer the full services of ATM networks, such as guaranteed bandwidth and Quality of Service.

VTAM enables multiprotocol attachments to ATM networks (both public and private) accessed through native ATM. These multiprotocol attachments are achieved through a high-performance data transfer (HPDT) multipath channel (MPC) connection to an IBM Open Systems Adapter. A single HPDT MPC connection can be simultaneously shared by multiple products using different communication protocols, provided those other products also support HPDT MPC connections. For example, APPN and non-APPN data can be simultaneously sent and received across an ATM network over the same HPDT MPC connection. For more information about HPDT MPC connections, see Multipath channel connections.