To guarantee the functions of the SwyxMobile even if the SwyxServer fails, it is possible to install an additional MobileExtensionManager on the standby SwyxServer (see also chapter Standby-SwyxServer). Both installed MobileExtensionManagers, on the master SwyxServer as well as on the standby SwyxServer, try to register with the available MobileExtensionManager users of the respective server. Since only one of these SwyxServers is active at a time, only the logon of one MobileExtensionManager (the active one!) will be successful. This will then process the calls.