After months of trying to figure out where the bottleneck in my relay is (I'm on gigabit down/up connection, but relay won't push more than 10mbps), I was poking through my NVG589 router's NAT Table and noticed
Total sessions available 2560 Total sessions in use 2048
Followed by a table containing almost entirely tor connections.
As far as I know, there is no way to increase the total sessions available. AT&T will not allow me to purchase my own router, so it looks like my only hope is to wait for AT&T to push out the NVG599 (which I was told was coming a month ago.)
Do any current relay operators have an NVG599? If so, could you check and see if it has a similarly low limit on total sessions (Diagnostics -> NAT Table in the NVG589). I've tried searching for this spec but it doesn't appear to even be in the user manual.