Been playing Reach without any severe issues since release, however over the past week it's gotten very laggy, to the point of being unplayable. I've contacted Microsoft and my ISP (at&t) to troubleshoot this but so far there's no fix.
I've done all the steps listed here:
...and I've also reconfigured the way the 360 is networked from auto to manual. Again, no improvement. Have also tried reinstalling the game.
When I do the network test on the 360 this is the error status report:
Any ideas on what else I can try?