rdisp/keepalive is a SAP Parameter attribute which is used to control Timer for check of unused connections information. This is available within R/3 SAP systems depending on the version and release level.
Below is the standard documentation available and a few details of the attributes values .
Specifies the maximum time in seconds after which the dispatcher checks
an SAP GUI connection in which there has been no data transfer during
this period. If the SAP GUI does not respond within the period defined
by
See SAP Parameter Documentation for full SAP documentation for this profile parameter.