LAN access timeout

If the client is communicating with CS Linux servers across a network for which connection charges are payable, you may want to ensure that the TCP/IP connection from the client is dropped automatically after applications on the client have stopped using CS Linux resources. This does not automatically disable the SNA software on the client; it remains active, and attempts to re-establish contact with a server if an application requires it at a later time.

The lan_access_timeout parameter (in the sna_clnt.net file for a Remote API Client on AIX or Linux, or the Registry for a Remote API Client on Windows) enables you to disable the SNA software on the client. The TCP/IP connection is dropped when none of the following events have occurred on the client for the specified time:

  • APPC or CPI-C conversations active (or attempts to start a conversation)
  • LUA sessions active
  • CSV TRANSFER_MS_DATA verbsfrom a Windows client
  • MS verbs (Linux clients only)
  • NOF verbs (except the query_central_logger or query_node_all verbs)
  • Administration commands (except the following events, which do not cause the client to restart the connection):
    • Error or audit messages logged by the client (these are logged locally on the client, even if central logging is being used)
    • The administration commands query_central_logger or query_node_all (these return the information that was available before the TCP/IP connection was dropped, and so may not match the current status of the LAN)
    • The NOF verbs query_central_logger or query_node_all (as for the equivalent administration commands)

In particular, the TCP/IP connection is dropped if you enable the SNA software but do not start any CS Linux applications on the client within the specified timeout.

When one of these events occurs while the TCP/IP connection is down, the client re-starts the attempt to contact a server, as described for the * and servername parameters in Client network data file (sna_clnt.net), or Servers.

Incoming Attaches for invoked TPs on this client cannot be accepted while the TCP/IP connection is down; the Attach is rejected as though the target system were inactive. This means that automatically started TPs on the client are not available if no other applications on the client are running and the TCP/IP connection has timed out. However, operator-started TPs on the client can be used at any time, because a Receive_Allocate verb issued by the TP re-establishes the TCP/IP connection.