About SNA LU6.2 Connections

Supported Interfaces

Following is a list of supported interfaces:

• Token ring
• Ethernet
• SDLC
• X.25 (QLLC)

Session Support

Connect:Direct for UNIX supports both independent and dependent LU6.2 sessions. Configuring independent LU sessions simplifies the management of communication between nodes and ensures appropriate recovery in some situations. Dependent LU sessions must be managed manually for communications between IBM® Connect:Direct nodes and do not recover properly in some situations.

The maximum number of independent LU sessions you configure defines the maximum number of concurrent transfers between nodes. The total number of sessions determines the number of UNIX transfers that can run simultaneously. Type an even number for the maximum number of sessions so that you can divide equally between the number of contention winner and contention loser sessions. The recommended number of maximum sessions is 8. The recommended number of contention winner sessions is 4. If supported, the recommended number of automatically established sessions is 4.

APPC Requirements

APPC requirements are described in the following list:

• Connect:Direct for UNIX uses a fixed transaction program (TP) name, NNV2DTF.
• Connect:Direct for UNIX uses basic conversations, sync level = confirm, no conversation level security, and no PIP (program initialization parameters).
• Do not specify the transaction program (TP) name in hexadecimal.

Configuration Requirements

Configuration requirements are described in the following list:

• The Connect:Direct for UNIX daemon must start the session manager, the LU6.2 communications component of Connect:Direct for UNIX. The Connect:Direct for UNIX daemon monitors for inbound ALLOCATEs and starts a session manager to handle the Process submitted by the remote node. The SNA communications package cannot start a session manager.
• Do not configure the TP as dynamically attachable or as an autostart program.
• Do not configure a path name to a Connect:Direct for UNIX program when you define the TP.
• For SNA packages that require that you provide a program name for a TP definition, you must type a program name that does not exist.

SNA Considerations

SNA considerations are listed in the following section:

• Connect:Direct for UNIX is tested with the following link LU6.2 types. Currently, not all link types are tested on all platforms.
  • Token ring
  • Ethernet
  • SDLC leased line
  • X.25 (QLLC)
• Connect:Direct for UNIX, as an LU6.2 conversation partner, supports any defined link type supported by the SNA package manufacturer. There are no special support or configuration requirements in Connect:Direct for UNIX when using different link types to communicate with the remote node.
• The RU size selected for use with Connect:Direct for UNIX can strongly affect the observed file transfer throughput. Connect:Direct for UNIX is tested with 1K, 2K, and 4K RU sizes, with inbound and outbound pacing set to 7. Use a 1K RU size to confirm basic functionality, and then use 2K and 4K RU sizes while monitoring network congestion. You can realize a significant gain in throughput by increasing RU sizes from 1K to 4K. Increasing the RU size beyond 4K or increasing the pacing above 7 generally provides marginal improvement, but can severely degrade network performance.

  VTAM resource names must be typed in uppercase.