just to flesh out this point ... Reload Router is a bit misleading.... it isn't only the DCERouter "device" that it reloads.
LMCE consists of many "DCE Devices". These are actually modules of software that run as processes under Linux, but could actually be software running on absolutely anything, as long as they can communicate using the DCE protocol. A LMCE machine (core, hybrid or MD) can and does run any number of DCE Devices.... LMCE actually isn't about the hardware, it is a network of DCE Devices (software programs) all communicating with each other through the DCE Router. These DCE Devices can be anywhere and hosted on any hardware, but obviously they are usually on Linux PCs running either as a core or MD. (an example is, Thom is currently writing a DCE device for Windows PCs so that they can collaborate with LMCE).
Plugins are much the same as DCE Devices, except instead of running as their own Linux process, they are hosted within the DCERouter device, and are usually a single instance for the whole house to perform coordinating roles. eg there are as many Xine_Player DCE Devices in your house as there are MDs, but only one Media Plugin, and that coordiates all the media being played back throughout the house by sending the appropriate media stream to the appropriate Xine_Player device.
Reloading the (DCE) Router causes the DCE Router to send the "reset" command to all DCE Devices in the system, then shutdown its own device and start back up again. Meanwhile, all the other DCE Devices' processes shutdown and restart, then attempt to reconnect to the DCE Router. The end result is reloading effectively resets all the LMCE software in the house and starts it up clean again without having to reboot all your hardware.
NB: there are one or two pieces of LMCE software that is not implemented as a DCE device, and so reloading the router will not reset those... eg UpdateMedia, StorageRadars, MySQL, etc but generally these are pretty solid and don't need resetting.