In recent weeks I had a 72 hour outage from my ISP and that's just not acceptable. In response I added a second connection ATT. ATTs service is also 1Gbps but confirming that speed has been difficult. No two speedtest apps provide the same numbers. But then there is the fine tuning that caused more problems. Sadly even after these changes there is still a difference in the speeds, however, at least one tool seems to have the expected performance.
So here are some notes on the ATT configuration....
There is a feature called "router behind router detection". This was defaulted to OFF but I turned it ON because I was putting a router behind the router. This turned out to be a bad decision as it janked my WiFi bridge connected to my router and it also messed up the Wifi in the modem. So just leave this off.
Next, since I was service incoming requests I needed to open a range of ports and direct them to my router. ATT's modem has a FIREWALL section where you can set the application/pinhole from the outside to the inside. First you navigate to the page, then select my router from the list of devices, then select the pinhole type.
If you select ALL then the router needs to be rebooted because you'll get the actual public IP address assigned to your router. Unfortunately this is one of the sticky points. When set to all there is huge loss of speed which I have yet to understand.
ATT indicates that when selecting this mode or changing targets you MUST reboot the target(s). DHCP get's a little upset and a reboot forces a proper release/renew.I ended up creating a user defined port range from 1 to 20000, for both TCP and UDP, so that I would include SIP+media. Although I did get an error message from ATTs modem that I was going to effect the TV I saved it anyway. After yet another reboot my data rates were so much closer to the advertised speeds.
I might mention that my router is a barebones/silent PC with 5 ethernet ports and no WiFi. I installed a dedicated pfSense ISO from a USB stick and at some point performed an upgrade. In my testing I also tried a Ubiquiti Edgerouter X, however, after all the reconfiguration I discovered that it was only capable of half the ATTs capacity. I'm sure that 500Mbps is more than sufficient but the price is right. One reason for trying the Edgerouter is because it's inexpensive, integrated, complete, backup/restore, and more importantly as a commodity piece of hardware I can get a replacement from Amazon in just a few days.