CM1150V Slow download with xfinity

kenb129 · ‎2022-08-15

Firmware Version

V4.12.04

Our service is 1200 down and we typically get about 950 down, but I don't have a network card that can do higher. Saturday our download speeds dropped to about 95 and every test I do flatlines right around there. I power cycled modem and Linksys MX4000 Velop mesh several times and same thing. Note that upload speed is the same it's been for the last year.

Calls to Comcast did no good since they claim that everything on their end looks good and I should contact Netgear. Well the modem warranty just expired and all they could do is send me a link with troubleshooting tips, but link doesn't work. So now my only Netgear choice is to pay $50 for them to possible tell me my modem isn't working and I can't do that.

There are no errors in the log.

Any thoughts?

Kitsap · ‎2022-08-18

A full reset of your MX4000 is most likely your best option. You may or may not need to reset the satellites.

After the router reset, a careful methodical restart of your network is called for.

Power down (remove the power cord) on your modem and disconnect the Ethernet cord to your router base.

Go to the manufacturer's to the manual to find the steps to reset the MX4000. Recommend you not be connected to the internet to do this. When complete, power it down and remove the power cord.

Power up your modem and give it plenty of time to boot and stabilize.

Connect the Ethernet cable between your router and your modem. Then power up your router. Give it plenty of time to boot and stabilize. The DHCP servers at your ISP may need a few minutes to establish a WAN IP address for your router. Remember, it is now different hardware than the last time the address was established with your computer connected direct to the modem.

Run your capacity tests from the PC direct connected to the router.

There may or may not be a firmware update available for your MX4000. I am not familiar with the Linksys approach to updates.

View solution in original post

plemans · ‎2022-08-15

Power levels look pretty good.

Do you have your logs?

What router do you have?

Reason I ask is it sounds more like your connection dropped from gigabit to 10/100mbps.

That can happen with lower quality cables. Make sure you have a good quality cat 5e or cat 6 cable between modem---router and then router---device your testing on.

netgears routers have a page you can check (wan port statistics page) that'll tell you connection link on the wan and lan ports.

Kitsap · ‎2022-08-15

The startup sequence for a separate modem and router network system is important.

On your CM1150V disconnect the coax cable, Ethernet cord, and power cord. Let them set for a few minutes.

On your MX4000 system, power it down and disconnect the power cord. Let it set while you go back to your modem. Connect the coax then the power cord only to boot the modem and let it stabilize.

Now connect the Ethernet cord to your MX4000 system and power it up. Give it plenty of time to boot and stabilize. Your MX4000 pulls a WAN IP address from the Comcast DHCP servers, and it may take a few minutes for that to happen.

Within the configuration of your MX4000, if you have the option to enable IPv6, do so. It will make your overall network run smoother.

Run your capacity test from an Ethernet connected PC and let us know the results. Recommend you install the Ookla native OS test application.

Like @plemans says, make sure you have a known good Cat 5e or Cat 6 Ethernet cable between your modem and router base.

kenb129 · ‎2022-08-16

5e is going to the router, but I noticed the plastic covering is split at the connector by the router, but no time to swap with a known good cable right now.

If cable replacement doesn't work I will try the other steps and see what happens.

Is there a way to run a cable from modem straight to PC? I unplugged router cable from modem and hooked up PC and I get "unknown network" with no internet.

plemans · ‎2022-08-16

the CM1150v might have more than 1 ethernet port but the majority of ISP's only support 1 connected device.

So if you want to direct connect your pc, you'll have to power the modem and pc off. then power the modem on with nothing connected and give it 2 minutes. Then power the pc on.

What router is it? Again, I'd see if it has something in its settings to check the connection speeds. That'll help determine what cable is the issue.

kenb129 · ‎2022-08-17

I substituted another 5e cable between modem and router and same result. I had no other time to troubleshoot last night.

I can't find anything in the Linksys app to show connection speed to see if it dropped from GB to 10/100.

I will try again to connect ethernet straight to modem, but when I did it last time PC showed "unknown network" and no internet. This is the first modem I've used that had this issue. Is there some setting that needs to be changed on modem or PC? I can try other ports on modem but I think I did that when new and same but will verify.

plemans · ‎2022-08-17

1. what router is it? you still haven't given us a model

2. the issue might be between router-device

3. again, if you direct connect a pc to the modem, you have to power off the modem and the device. ONLY have the pc connected to the modem as most isp's only support 1 device connected to the modem. Then power the modem on and wait 2 minutes, then power the computer on.

kenb129 · ‎2022-08-17

@plemans

1 - Linksys Velop MX4000 series, two nodes

2 - I tried several wireless devices and wired PC

3 - I unplugged router cable and plugged in PC in same port, but I did I did NOT try the exact steps you suggested. I will try that tonight.

plemans · ‎2022-08-17

Not sure in the velops if there's a way to check the wan/lan connection to see if its connecting at gigabit speeds or at the 10/100mbps speeds. You could check on their forum or support site to see.

kenb129 · ‎2022-08-17

I was able to get the pc to connect straight from the modem and I'm getting normal speeds, so it's something to do with my router.

Should I just reset the whole system and reconfigure the mesh network or try something else? I know signal going into router is good unless two cables went bad at same time which is unlikely.

Kitsap · ‎2022-08-18