I have to say i think the biggest mistake you have made is take a great game give it to people that cannot it seems run a server very well all i seem to be getting is halo reach server no available halo 4 the same halo 3 same then it kick you off for no reason please get Bungie back they knew what to do how to keep thing running great not you have it you are spoiling it 343 please 1 get the servers work right 2 if you cannot get back Bungie
You seem to be the only one reporting that the Halo 3, Reach & Halo 4 servers are down, so by the looks of it, it’s on your end.
Have you tried clearing your Xbox 360’s cache?