This read-create boolean identifies whether this endpoint acts as the master, or calling party, of the SPVC call setup (true) or the slave, or called party (false), where the networking entity initiating the call would typically be the master. An admin cares because several other per-connection parameters, like PCR, CTD, and routing priority, are only meaningful or settable on the master endpoint, so this setting determines which side of the connection controls those parameters. For example, if an admin tries to set the routing priority on an endpoint but the change is rejected, checking this mastership flag would reveal that the endpoint is configured as a slave, where that parameter can't be set.