Keepalive Interval (KAINT)

This attribute is used to specify a timeout value for a channel.

The Keepalive Interval attribute is a value passed to the communications stack specifying the Keepalive timing for the channel. It allows you to specify a different keepalive value for each channel.

You can set the Keepalive Interval (KAINT) attribute for channels on a per-channel basis. On platforms other than z/OS®, you can access and modify the parameter, but it is only stored and forwarded; there is no functional implementation of the parameter. If you need the functionality provided by the KAINT parameter, use the Heartbeat Interval (HBINT) parameter, as described in Heartbeat interval (HBINT).

For this attribute to have any effect, TCP/IP keepalive must be enabled. On z/OS, you do enable keepalive by issuing the ALTER QMGR TCPKEEP(YES) MQSC command. On other platforms, it occurs when the KEEPALIVE=YES parameter is specified in the TCP stanza in the distributed queuing configuration file, qm.ini, or through the IBM® WebSphere® MQ Explorer. Keepalive must also be switched on within TCP/IP itself, using the TCP profile configuration data set.

The value indicates a time, in seconds, and must be in the range 0 - 99999. A Keepalive Interval value of 0 indicates that channel-specific Keepalive is not enabled for the channel and only the system-wide Keepalive value set in TCP/IP is used. You can also set KAINT to a value of AUTO (this value is the default). If KAINT is set to AUTO, the Keepalive value is based on the value of the negotiated heartbeat interval (HBINT) as follows:

Table 1. Negotiated HBINT value and the corresponding KAINT value
Negotiated HBINT	KAINT
>0	Negotiated HBINT + 60 seconds
0	0

If AUTO is specified for KAINT, and it is a server-connection channel, the TCP INTERVAL value is used instead for the keepalive interval.

This attribute is valid for all channel types.

The value is ignored for all channels that have a TransportType (TRPTYPE) other than TCP or SPX