This read-write value tells the PXM controller card whether this connection endpoint should behave as the master or slave side of the circuit-emulation connection, with a third unknown value used specifically to distinguish an MGX8220 shelf's Session Manager from an MGX shelf's, since MGX shelves require explicit slot/port/... parameters on connection setup while MGX8220 does not. An administrator setting up a connection on an MGX shelf must ensure X/Y/P parameters are supplied if cesMastership indicates the unknown type, or the PXM's SPM will reject the request. On an MGX8220 shelf, by contrast, a channel can still be added without those parameters even when this object is set to the unknown type.