Why Did This Fix Work?

I connect to the computer and the television by Ethernet cable. Yesterday for no apparent reason while the computer/ modem - router connection was still solid when I went to stream SlingTV nothing. I got that message that Ethernet was not connected and I know damn well it was just as it has been for the past 2 weeks. In fact it showed that the Ethernet was connected in one of the blurbs but there was no hand shaking going on. Wifi did not work either even though I never use it but when I tried it would not connect. I was getting really pissed off and after a number of steps troubleshooting (on my own) I was thisclose to taking advanatage of Costco's lenient return policy. I had tried different Ethenet cables and different ports on the unit but nothing as well as shuting everything down for an hour and then over night. I was just about to call up support which is almost always a nightmare (chat was useless on another earlier question which after giving the rep a bad rating I received an email explaining what the problem was though by that time I had GOOGLED the answer myself)  It wasn't until I folllowed these directions that brought it back to life. Unplug modem - router, TV. Do not disconnect any Ethernet cables. Plug in modem - router first and wait for connections to lite up. Well that did it. Ethernet -> TV -> modem - router were talking to each other again. So I am an idiot and would like to know why this partiuclar solution kick started the Ehternet connection again. Kiss of death posting this. TIA.