rdisp/max_comm_entries is a SAP Parameter attribute which is used to control Maximum number of communication entries 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 .
Maximum number of communication entries for an application server. Every
RFC or CPIC communication with a partner program requires an entry. If
the initiator and recipient of an RFC/CPIC program are running on the
same application server, two entries per communication are required.
See SAP Parameter Documentation for full SAP documentation for this profile parameter.