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Internet not quite right after purchasing NetGear Nighthawk CM2000 [Resolved Jan 28, 2021]

washbb
New Poster

Internet not quite right after purchasing NetGear Nighthawk CM2000 [Resolved Jan 28, 2021]

I recently signed up for Xfinity. I purchased the Netgear Nighthawk CM2000 (modem only, no voice or WiFi router included), hoping to not rent the xFi Gateway anymore. Initially, I took out the xFi Gateway and plugged in the Netgear modem.

 

The indicator lights were all white and looked fine - though the "download" light is always blinking white constantly, while the "upload" light is almost always solid white.

 

However, I started to run into issues.

  1. Only a few devices could work via the LAN port of the Netgear CM2000, while others didn't. (I inferring it was because those devices had a max Ethernet speed of 100 Mb/s, and anything capable of 1,000 Mb/s failed to connect via Ethernet.)
  2. (Though not directly related,) I set up my own router (Linksys WRT3200ACM). However, my own router failed to pick up any internet connection at all during the whole process.

This is all sort of strange, because a technician had already came in about 2 days ago to set up the xFi Gateway, so no other coaxial connections should be loose or anything like that.

 

I had some more "detailed" issues? Definitely not sure if these could be fixed by a technician or not.

  • Additionally, when I accessed the modem at 192.168.100.1 in my browser and explored the Event Log under the Advanced options, I noticed a constant stream of messages with "(Critical (3))" priority about: T3 timeouts, "Ranging Request Retries exhausted", and "No Ranging Response received". The messages keep cycling through in this order. (I'm not sure if posting the raw log info is extremely sensitive information.)
  • Lastly, under the Basic options, the downstream channel power values are rather high and not under absolute values of 7 dBmV (somwhere between 8-11 dBmV), while only 2 out of 8 upstream channels have power levels of 39-41 dBmV (so, somewhat normal values) - according to some nebulous source while web searching. (Also I wasn't sure if posting this info was too sensitive.)

 

I'm sort of getting desperate at this point, because I had double-checked to make sure I purchased a compatible modem for Xfinity, and I've read other stories (some on them marked resolved and others not) on how some poor souls even went out to buy duplicate modems (in case there were defects) or entirely different modems to no avail, only to find some issue that couldn't be fixed by doing what they did.

Gottahavit
Regular Contributor

Re: Internet not quite right after purchasing NetGear Nighthawk CM2000

Did you do self activation of the new modem?  did you look on the internet status page i your account to see if it reports issues?  You may have to have a chat rep activate your modem properly.  I ran into this on the xFi, it worked but poorly after self activation, site reported issues, called rep fixed in 5 minutes easy peasy.

washbb
New Poster

Re: Internet not quite right after purchasing NetGear Nighthawk CM2000

Ok, so things were resolved today. A Comcast technician had to come in.

 

  • The main issue was most likely due to the previous contractor technician, who split a neighbor's coaxial cable (which may or may not have been in service - I'm guessing) while trying to avoid going outside. So, something among the lines of this happened: there was sufficient "wiring" for download, but not for "upload" so that the purchased router could be recognized by anyone in the Comcast call center. (Maybe some unspecified lower requirements of the xFi Gateway explains some of the issues I saw?) Additionally, the Comcast technician had to go outside to formally activate the Comcast/Xfinity service. Luckily for me, the issues I faced had to be resolved by a technician - not the user end.
  • Afterward, I wasted a lot of time trying to get the Linksys WRT3200ACM router working - until I recalled what the second Comcast technician told me: a modem can only "remember" the first device plugged into the LAN/ethernet port. Trying to plug any second or later device into the modem (for a single, dedicated wired internet connection) will result in the computer/laptop/phone not being recognized. So, when I finally remembered this tip, my Linksys router started working - so I most likely didn't to play with any other settings, cloning my laptop's MAC address, or anything else. (Fortunately, I saved myself from resetting my router - which would've been some work, since I installed OpenWRT on the Linksys router and previously believed maybe that was the reason why the Linksys router didn't work.)

Anyways, I'll marked this here (even if there's no real "solution"), in case if this could help someone out there.