rdisp/ms_keepalive is a SAP Parameter attribute which is used to control Timer for check of message server connection 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 after which the dispatcher checks the message
server connection in which there has been no data transfer during this
period.
If the message server does not answer within the time period defined in
See SAP Parameter Documentation for full SAP documentation for this profile parameter.