rdisp/max_websocket_connections is a SAP Parameter attribute which is used to control Size of the WebSocket table 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 .
This parameter specifies the size of the WebSocket table. In this table
the Dispatcher manages an entry for every WebSocket connection. This
parameter then restricts the maximum number of WebSocket connections.
See SAP Parameter Documentation for full SAP documentation for this profile parameter.