I’ll start by conceding that the problem I’ll be discussing was MINE, not Xfinity’s.
But we didn’t know that for a long time.
Recently my 2 year contract with Xfinity lapsed and my bill jumped $50 per month. I called to renegotiate.
They responded with a new plan that had the same TV channels and bumped the Internet speed from 200Mbps to 800Mbps. While I didn’t NEED that speed increase, faster is always better.
So after a couple of days, I tried a speedtest.
Hmmm. 250Mbps. What’s up with that?
So I looked at my modem, a CISCO DPC3008. While it is DOCSIS 3.0, it only has 8 download channels. This limits it to 340Mbps.
Maybe that was the problem. Not.
But it was time for a new modem anyway so I got an Arris SB6190. It was still DOCSIS 3.0 but had 32 download channels for 1.4Gbps.
Maybe that would fix it. Not.
So I called Xfinity for support. I got a representative in Honduras who was very thorough. His thinking was that there was a cap still in place somewhere but he couldn’t see it. So he dispatched a technician.
The technician showed up. His diagnosis was that I had a bad coupling on the coax going into the modem. Not.
I was still at 250Mbps.
I placed another service call. This time the technician didn’t even show up. He just called.
He said that I needed a different bootfile. His attempts at downloading a new one didn’t work. He said that was because I needed a DOCSIS 3.1 modem.
And that’s the end of the Xfinity lack of support story. Hours and hours of my time. Several hours of Internet down time while replacing/testing hardware. Hundreds of dollars spent. Two technicians dispatched neither of whom was capable of diagnosing a problem.
So I decided to take the advice I gave to one of my Unix admins when he was troubleshooting a dial-out modem on an HP 9000.
FOLLOW THE WIRE.
I took a laptop with a gigabit Ethernet port and plugged it directly into the Netgear CM2000.
Bingo! I got 650Mbps.
Then I plugged that laptop into the LAN port on my router.
250Mps.
As Pogo said, “We have met the enemy, and he is us.”
So off to Google I went.
What I FINALLY found was that the RT-AC68R defaults to using the CPU to perform NAT acceleration. But the RT-AC68R has dedicated hardware that it can use. When I dug down into the settings and switched “NAT Acceleration” to “Auto”, all was well!
The switch point where you should use the dedicated hardware is 150–200Mbps so I hadn’t stumbled on it earlier.
Then I switched back to the Arris SB6190 and returned the Netgear CM2000. I still got 850Mbps.
Lessons learned: 1) Fast home Internet is a challenge and 2) Xfinity is no help.
Originally published at https://blog.benmoore.info.
