I've been going in circles with Frontier and Xbox trying to get a new router (Actiontek F2250) to work properly with my XB1. The XB1 will totally loose connection/lag/rubberband/kick me out of games/etc because of network issues. My NAT is open but my speeds as tested on the XB vary from 0 download/1.5 upload to 15 download/2 upload - and it seems totally random as to when it decides to disconnect.

Frontier support found nothing wrong with the lines and recommended disconnecting phones because they might be causing issues over the DSL lines. This did not help.

I'm wired to the router, have a static IP for the XB1 and have port forwarded as follows (as per MS instruction as well as other sources):

TCP or UDP
53

TCP or UDP
3074

UDP
88

TCP
80

UDP
500

UDP
4500

UDP
3544

TCP or UDP
16000

TCP or UDP
1863

TCP or UDP
3075

I plan on calling Frontier support again tomorrow to see if I can figure out if there's something hinky going on between the XB and router but thought I'd get any thoughts here first.

After multiple outages caused by backhoes and wires one technician decided my dsl modem was the problem. The actiontek modem of course did not fix the problem and it's a router and even their pass through mode was jot transparent enough to make several things work. But to prove it was still broken I had to use it. I noticed one thing that may be applicable to your issue. Every two minutes it does something that causes it to delay packets for multiple hundreds of ms. I started a ping to the local dslam and it was on the order of 13ms but every two minutes one would have a rtt over 500ms. I let the ping rin to a log file for two days and every two minutes during that period it was slow. At the end of two days it was within two seconds of and exact multiple of when I started. I dug around in the garage and got out a plain adsl2 modem my son had when he was in att area and hooked it up to line and my router. No more delayed pings. Actiontek is junk