I doubt it's your internet service. I haven't been able to play destiny for 4 days and I have frontier. I have never had an outage with my service and still don't. Every time this game gets error codes is because bungie still after 3 years can't figure out how to fix their game.
Bungie has put out a service alert, they are having some issues with the baboon and nightingale errors I believe.
Unless bungie has stated they are having issues then it's more then likely user side. I've never had issues with staying connected. Even back when I was using wifi. Sure I'd get the odd error.
But if bungie was actually responsible for people not being able to stay connected all the time it would affect everyone single player which it doesn't. That's why it's probably something on your end. Also could be the issue bungie is having right now read the service alert see if it applies to you.