ms/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 before the message server checks
inactive connections. A data packet is sent to the client for the check.
Value 0 deactivates this check.
See SAP Parameter Documentation for full SAP documentation for this profile parameter.