The following controller and device configuration options can affect system performance during communications error recovery.
AUTODLTDEV (1440, *NO, or wait-time): Device descriptions that are automatically created by the system may also be automatically deleted by the system. The default is to delete devices that were automatically created after 1440 minutes (24 hours) if they have not been used in that time period.
Specifying the default has the potential side-effect of having device descriptions deleted over weekends. This can cause a system slow-down. For example, when users reconnect on Monday morning (after a 48-hour period of system inactivity), they may discover that they need to re-create their device descriptions.
It may be desirable to have the AUTODLTDEV parameter default to a value larger than 24 hours; 72 hours may be more appropriate to cover weekends. Use a model controller to change this value for any autocreated controller descriptions.
The default value for devices that are attached to automatically created APPN virtual controllers is 10,000 minutes.
The AUTODLTDEV parameter is on the CHGCTLAPPC, CRTCTLAPPC, CHGCTLHOST, and CRTCTLHOST commands.
INLCNN (*DIAL or *ANS): In error recovery scenarios, the actions that are taken to recover the controller depend on whether the controller description was created with *DIAL or *ANS. The default value for INLCNN is *DIAL. The INLCNN
parameter is on the CHGCTLxxx and CRTCTLxxx commands.
Consider the following in creating the controller description:
v Use INLCNN(*DIAL) for AS/400-to-AS/400 connections when either system may initiate a connection with the other.
Note: The time at which the system actually attempts to *DIAL depends on the setting of the APPN, DIALIMMED, MINSWTSTS, and CTLOWN
parameters. See Table 6 on page 116 and Table 7 on page 116 for details on the interactions of these parameters.
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v For PCs, use INLCNN(*ANS) to avoid unnecessary recovery attempts when the PC shuts down.
APPN Minimum Switched Status: The default value for the APPN minimum switched status (MINSWTSTS) parameter is *VRYONPND. Specify this to make APPN controllers in vary on pending status available for APPN route selection.
Specify MINSWTSTS(*VRYON) to limit the routes that APPN recognizes as
available. This prevents APPN from selecting routes that have a controller in varied on pending status on one system, but are varied off or inoperative on an adjacent system.
Note: MINSWTSTS(*VRYON) requires SWTDSC(*NO).
The setting of the MINSWTSTS parameter affects when the system will attempt to dial out to a remote system. Consequently, this affects how the AS/400 attempts to recover after a connection to a remote system is lost. The MINSWTSTS parameter can also play a role in system behavior when a configuration error has occurred.
For example, if an incorrect remote NETID is configured, the value of MINSWTSTS determines the controllers that are used to attempt to locate a potentially
nonexistent remote system.
SWTDSC (*YES or *NO): By default, the value for SWTDSC is *YES. This configuration is recommended for switched connections. It allows a switched line to be disconnected when the application is no longer using the line.
For PCs that are connected to a LAN, consider using SWTDSC(*NO). Connections between PCs that are running Client Access/400 and an AS/400 may be
disconnected automatically if the following conditions exist:
v The Client Access/400 router is started
v An application such as a 5250 emulation session or a network drive is not running over the connection
v The application does not start within the time limit that is specified by the disconnect timer (DSCTMR) parameter
Specifying SWTDSC(*NO) keeps the connection to the AS/400 active, even if no applications are started.
The SWTDSC parameter is on the CHGCTLxxx and CRTCTLxxx commands.
Disconnect Timer (DSCTMR) parameter
The disconnect timer (DSCTMR) parameter controls the time before a connection without activity is dropped, or the amount of time to delay the automatic disconnection. The default value is 170 seconds. The range is 0–65535 seconds.
The DSCTMR parameter is on the CHGCTLxxx and CRTCTLxxx commands.
APPC Controller Recovery Summary: The action the system takes when APPC controller descriptions go into recovery depends on the settings of the parameters previously discussed. In addition, there is interaction between different parameters.
The tables that follow help describe when an AS/400 controller description on a LAN will attempt to reconnect to the remote system. The tables should be used to help you select the appropriate configuration parameters to best optimize system behavior when APPC controllers that represent PC clients go into error recovery.
In all cases in the following tables:
v The tables address APPC-attached PCs on a LAN that use Client Access/400.
This often is the environment where the number of users is the largest. Other environments may result in different actions.
v The tables assume the following configuration values:
DIALIMMED(*LINKTYPE) For LANs, this is *IMMED.
Note: If DIALIMMED(*DELAY) is used, no dial attempts are made for the recovery or vary on cases.
APPN CP sessions
In all cases, there are no APPN CP sessions. APPN CP sessions will change when the system attempts to connect to the remote system.
Table 6. When does the AS/400 attempt to connect the remote system?
MINSWTSTS INLCNN APPN CTLOWN Power PC
Off (recovery)
Manual Vary On
*VRYONPND *DIAL *YES *SYS Dial not
attempted
Dial is attempted
*VRYONPND *DIAL *YES *USER Dial not
attempted
Dial is attempted
*VRYONPND *DIAL *NO *SYS Configuration not allowed
N/A *DIAL *NO *USER Dial not
attempted
Dial is attempted
*VRYONPND *ANS *YES *SYS Dial not
attempted
Dial not attempted
*VRYONPND *ANS *YES *USER Dial not
attempted
Dial not attempted
*VRYONPND *ANS *NO *SYS Configuration not allowed
N/A *ANS *NO *USER Dial not
attempted
Dial not attempted Table 7. MINSWTSTS(*VRYON) affect on AS/400 attempts to connect to the remote system
APPN INLCNN CTLOWN SWTDSC Power PC
Off (recovery)
Manual Vary On
*YES *DIAL *SYS *YES Configuration not allowed
*YES *DIAL *SYS *NO Dial is
attempted
Dial is attempted
*YES *DIAL *USER *YES Configuration not allowed
*YES *DIAL *USER *NO Dial is
attempted
Dial is attempted In all cases where a dial is attempted, and the remote system is a PC that uses Client Access/400, that dial attempt will fail with the following message:
v CPA57EF to QSYSOPR (Controller contact not successful)