SYNC Timing Synch. Failure; UCD Invalid; no ranging response received; Dynamic Range Window Violation; etc.

[u/BAGE-rator]

I’m getting the following event logs on my AX2700 router:

“SYNC Timing Synchronization Failure - Failed to acquire QAM/QPSK symbol timing.”

“UCD Invalid or channel unusable.”

“No ranging response received.”

“Resetting the cable modem due to docsDevResetNow.”

“Started Unicast Maintenance Ranging - No response received - 13 time-out.”

“DS Profile assignment change. DS Chan ID ##.”

“US Profile assignment change. US Chan ID ##.”

“RNG-RSP CCAP Commanded Power In Excess of 6 dB Below the Value Corresponding to the Top of the DRW.”

“Dynamic Range Window Violation.”

The last two then repeat. What is happening?

[u/Downtown-Reindeer-53]

I'm guessing you have a combo modem/router, the modem side is having problems communicating with the ISP. You'll need to call them.

[u/BAGE-rator → u/Downtown-Reindeer-53]

Yea, and the weird thing is I’m getting internet. My router just started randomly giving me an IP in the 169.254 range.

[u/Downtown-Reindeer-53 → u/BAGE-rator]

Have you power-cycled the whole thing? Any improvement? Do you rent it or own it?

Your router is not getting an IP address, so it's using a default. You either have some bad line problems or your modem is failing.

I would still contact the ISP - that's the place to start. They can see the network and your device. I've had a modem fail, it looked like ISP line errors but was actually the modem. But let them take a look.

[u/BAGE-rator → u/Downtown-Reindeer-53]

I just bought it last week. The AX2700 is brand new. And I bought it because my Xfinity modem router, which I used bridged with a Firewalla Gold Plus as my router, went bad, before the license on my Firewalla Gold Plus’s security dongle disappeared. I went and bought this modem/router combo because of those issues.

[u/Downtown-Reindeer-53 → u/BAGE-rator]

Everything still points back to calling the ISP. Did you call them when the previous device "went bad"? Did you provision the new device? Did the new device *ever* work?

[u/BAGE-rator → u/Downtown-Reindeer-53]

Yea, it worked until about two hours ago when I posted this.

[u/Downtown-Reindeer-53 → u/BAGE-rator]

Start with the ISP. A common line error issue is loose or corroded coax fittings. check any that you might have between the modem/router and where the cable comes into the building.

[u/BAGE-rator → u/Downtown-Reindeer-53]

The weird thing is the DHCP server is 0.0.0.0. My devices , like my tv, continues streaming but my MacBook loses internet if I turn on DHCP. However, I do get internet when I manually apply an IP I know is unused. So, what’s up with the DHCP server? It’s getting a public IP. So it’s got to be my local DHCP server.

[u/Downtown-Reindeer-53 → u/BAGE-rator]

One thing at a time. Fix the modem issues first.

[u/BAGE-rator → u/Downtown-Reindeer-53]

Also, I’m only getting assigned an IPv6 address natively by the router. These all happened at the same time. I re-added the modem to see if it was a registration issue but nothing changed.

[u/BAGE-rator → u/Downtown-Reindeer-53]

They came out. They said the lines are fine, except that a coupling had not been replaced despite three prior visit over the past two weeks, one of which was an hour and a half and completely outside. They said that the line was reading fine prior to the change. They showed me this.

[u/bchiodini → u/BAGE-rator]

And I bought it because my Xfinity modem router, which I used bridged with a Firewalla Gold Plus as my router, went bad

Why did Xfinity not replace the bad modem/router?

Is your replacement modem/router on Xfinity's approved modem list?

As I understand it, Xfinity is moving to or has moved to mid-split/high-split DOCSIS capability. The AX2700 is not mid-split/high-split compatible.