The SessionId (Get) method retrieves the SessionId property, as specified in the property table in section 3.2.4.9.
[propget] HRESULT SessionId( [out, retval] ULONG64* id );
id: Receives the session identifier. Only the lower 2 bytes of the id value are specified; therefore, the valid range of these lower 2 bytes is from 0x0000 to 0x003F. The upper 6 bytes of the id MUST be ignored.
Return Values: This method MUST return an HRESULT with the severity bit clear on success as specified in [MS-ERREF]; otherwise, it MUST return one of the errors as defined in 2.2.1 or one of the errors as defined in [MS-ERREF] section 2.1.