rdisp/rfc_max_comm_entries is a SAP Parameter attribute which is used to control Quota for use 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 .
Quota for the maximum number of communication entries that the user can
occupy. If this value is exceeded, no further resources are returned to
the caller, so that the server does not become overloaded. The value is
given as a percentage. In other words, it is dependent on the value
currently set in the profile. The parameter
See SAP Parameter Documentation for full SAP documentation for this profile parameter.