Router re-boot

Hi all, at approximately 5.00am this morning my Sky router decided to re-boot itself. I initially thought it might be a firmware update, but it is still showing the same firmware version. I checked my CCTV looking for a power outage, but again no power cut. My question therefore is what could cause the router to re-boot itself, apart from obviously a manual re-boot via the router's interface or manually pulling the power on it. Just to add this router has always been 100% reliable. Thanks in advance

It could be the router had a software crash and rebooted automatically much the same as a PC would. It may be that a table got overloaded causing the error. If it doesn't happen often then it is unlikely to be anything to worry about.