I am writing about a problem with my PC connected to internet by ethernet. I have an Amplifi Alien Router and a Nighthawk CM2000 modem purchased from Xfinity. There are no splitters in the cable leading to my home or inside my home. It only connects to the one modem. I have been using this set up for nearly a year without any trouble.
About ten days ago, my internet started randomly disconnecting every 5-10 minutes. I first noticed it while gaming (getting kicked off game), but I have determined it also impacts web browsing. The modem app says "A network change was detected" when this happens.
About 2 days ago, while attempting to work on the issue the modem now reads Cable Connection status as "poor" at all times, and my speed test is under 100 mbs (I have the highest level plan 1.2 GB I believe). Before I was getting up to 800 mbs.
I have tried many many things. I have reset and restarted the modem, router and PC dozens of times. I have plugged modem directly into PC without any change. When I use the xfinity assistant, it says my connection and modem are good.
My cable connection report looks like this except the downstream status is yellow (not sure why it is green in copy and paste:
Cable Connection
Cancel Apply
Cable Diagnostic
Status: Poor
Action: [Partial Service] If the Partial Service mode does not go away within a few hours (Click the Refresh button after each step): 1) Make sure the coaxial cable is tightly connected. 2) Remove any unnecessary splitters. 3) Replace any required ones. 4) Contact your service provider for troubleshooting help. [Downstream SNR] Try these actions (Click the Refresh button after each step): 1) Make sure the coaxial cable is tightly connected. 2) Remove any unnecessary splitters. 3) Replace any required splitters. 4) Contact your service provider for troubleshooting help.
CM Status:
Downstream Status:
Upstream Status:
Refresh Save Cable Diagnostic Info
Advanced Information
Frequency Start Value
This field below allows you to modify the frequency the cable modem start with its scan during initialization and registration. Enter the new start frequency and restart the cable modem for it to take effect.
Starting Frequency
Startup Procedure
Procedure
Status
Comment
Acquire Downstream Channel
591000000 Hz
Locked
Connectivity State
OK
Operational
Boot State
OK
Operational
Security
Enabled
BPI+
IP Provisioning Mode
Honor MDD
IPv6 only
Downstream Bonded Channels (Partial Service)
Channel
Lock Status
Modulation
Channel ID
Frequency
Power
SNR
Correctables
Uncorrectables
1
Locked
QAM256
28
591000000 Hz
-0.9 dBmV
35.9 dB
0
0
2
Locked
QAM256
1
429000000 Hz
0.2 dBmV
44.6 dB
0
0
3
Locked
QAM256
2
435000000 Hz
-0.1 dBmV
44.3 dB
0
0
4
Locked
QAM256
3
441000000 Hz
-0.3 dBmV
44.2 dB
0
0
5
Locked
QAM256
4
447000000 Hz
0.2 dBmV
44.3 dB
0
0
6
Locked
QAM256
5
453000000 Hz
-0.1 dBmV
43.9 dB
0
0
7
Locked
QAM256
6
459000000 Hz
-0.2 dBmV
44.1 dB
0
0
8
Locked
QAM256
7
465000000 Hz
0.3 dBmV
44.1 dB
0
0
9
Locked
QAM256
8
471000000 Hz
0.1 dBmV
44.2 dB
0
0
10
Locked
QAM256
9
477000000 Hz
-0.1 dBmV
44.0 dB
0
0
11
Locked
QAM256
10
483000000 Hz
0.1 dBmV
44.2 dB
0
0
12
Locked
QAM256
11
489000000 Hz
0.2 dBmV
29.3 dB
43
0
13
Locked
QAM256
12
495000000 Hz
-0.4 dBmV
33.2 dB
0
0
14
Locked
QAM256
13
501000000 Hz
-0.2 dBmV
31.6 dB
0
0
15
Locked
QAM256
14
507000000 Hz
-0.2 dBmV
30.4 dB
0
0
16
Locked
QAM256
15
513000000 Hz
-0.8 dBmV
37.4 dB
0
0
17
Locked
QAM256
16
519000000 Hz
-0.5 dBmV
43.9 dB
0
0
18
Locked
QAM256
17
525000000 Hz
-0.4 dBmV
43.9 dB
0
0
19
Locked
QAM256
18
531000000 Hz
-0.8 dBmV
27.7 dB
32500
14
20
Locked
QAM256
19
537000000 Hz
-0.5 dBmV
26.4 dB
9653402
1414263
21
Locked
QAM256
20
543000000 Hz
-0.3 dBmV
33.0 dB
0
0
22
Locked
QAM256
21
549000000 Hz
-0.9 dBmV
43.5 dB
0
0
23
Locked
QAM256
22
555000000 Hz
-1.0 dBmV
43.4 dB
0
0
24
Locked
QAM256
23
561000000 Hz
-0.7 dBmV
43.6 dB
0
0
25
Locked
QAM256
24
567000000 Hz
-0.8 dBmV
43.4 dB
0
0
26
Locked
QAM256
25
573000000 Hz
-0.9 dBmV
43.3 dB
0
0
27
Locked
QAM256
26
579000000 Hz
-0.3 dBmV
43.7 dB
0
0
28
Locked
QAM256
27
585000000 Hz
-0.8 dBmV
43.4 dB
0
0
29
Locked
QAM256
29
597000000 Hz
-0.1 dBmV
42.1 dB
0
0
30
Locked
QAM256
30
603000000 Hz
-0.6 dBmV
43.4 dB
0
0
31
Locked
QAM256
31
609000000 Hz
-0.5 dBmV
43.4 dB
0
0
32
Locked
QAM256
32
615000000 Hz
-0.1 dBmV
43.5 dB
0
0
Upstream Bonded Channels
Channel
Lock Status
US Channel Type
Channel ID
Symbol Rate
Frequency
Power
1
Locked
ATDMA
19
5120 Ksym/sec
29200000 Hz
50.8 dBmV
2
Locked
ATDMA
18
5120 Ksym/sec
22800000 Hz
50.0 dBmV
3
Locked
ATDMA
17
5120 Ksym/sec
16400000 Hz
49.3 dBmV
4
Locked
ATDMA
20
5120 Ksym/sec
35600000 Hz
50.8 dBmV
5
Not Locked
Unknown
0
0
0
0.0 dBmV
6
Not Locked
Unknown
0
0
0
0.0 dBmV
7
Not Locked
Unknown
0
0
0
0.0 dBmV
8
Not Locked
Unknown
0
0
0
0.0 dBmV
Downstream OFDM Channels
Channel
Lock Status
Profile ID
Channel ID
Frequency
Power
SNR / MER
Active Subcarrier Number Range
Unerrored Codewords
Correctable Codewords
Uncorrectable Codewords
1
Locked
0 ,1 ,2 ,3
193
957000000 Hz
-3.52 dBmV
39.4 dB
148 ~ 3947
3945465
3910410
584
2
Not Locked
0
0
0 Hz
0 dBmV
0 dB
0 ~ 4095
0
0
0
Upstream OFDMA Channels
Channel
Lock Status
Modulation / Profile ID
Channel ID
Frequency
Power
1
Not Locked
0
0
0 Hz
0 dBmV
2
Not Locked
0
0
0 Hz
0 dBmV
Extended Upstream Transmit Power
Current System Time:Thu Oct 31 12:15:55 2024
System Up Time:00:10:51
From my tests and removal of the router, I can only conclude that I have a problem with the modem or connection to the modem. I have used different ethernet cables with no relief. Any thoughts would be welcome, even if it is "you need to have a service visit."
Several downstream channels have out of spec SNR values (too low), and all the upstream channels have borderline power levels (too high). Network connection problems like this are often due to poor coax connections or damaged coax cable, usually in or near your home. Running the cable through a surge protector, a defective splitter, or too many splitters can cause signal problems as well. If there is an amplifier in the line make sure it's getting power.
If you want to troubleshoot this yourself, please see Internet Troubleshooting Tips. If you can't find the problem or you'd rather have Comcast take care of it and an employee does not respond to your message here, call them at the phone number on your bill or 1-800-Comcast, or use one of the options on https://www.xfinity.com/support/contact-us/. It's not likely they can fix the problem remotely. If not, insist they send a tech out to identify the cause and correct it.
If the tech finds bad coax, splitters, amplifiers, or connections in your home (even if Comcast originally supplied them) you'll probably have to pay for the visit (approx $100) unless you have their Service Protection Plan ( https://www.xfinity.com/support/articles/service-protection-plan, closed to customers that don't already have it). If the trouble is due to a faulty Comcast rental device or anything outside your home you shouldn't be charged.
Please be aware that there are 2 kinds of responses in this Forum: Replies and Comments. When you Comment on a post by scrolling down to "Comment on this post here...", I am notified of your response. But if you select Reply, I am NOT notified and may not be aware of your response.
Hi there user_wslq80! Thank you so much for reaching out regarding your service issues you are having recently with your Internet service. You are in the right place and we are happy to take a look at your connection remotely and see if we can get it fixed.
Please send us a direct chat message with your full name and complete service address to “Xfinity Support”. To do so, click on the chat icon located at the top right of this forums page.
Here's the detailed steps to direct message us:
Click "Sign In" if necessary
Click the "Direct Message” icon (upper right corner of this page)
Click the "New message" (pencil and paper) icon
Type "Xfinity Support" in the to line and select "Xfinity Support" from the drop-down list
Type your message in the text area near the bottom of the window
@user_wslq80 Thank you for letting us know that you have a technician coming this morning. Please let us know how you make out and if you need further assistance. We will also set a reminder to follow up, in case we haven't heard from you. It's important to us that your service issues be 100% resolved.
I am an Official Xfinity Employee. Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership. We ask that you post publicly so people with similar questions may benefit from the conversation. Was your question answered? Please, mark a reply as the Accepted Answer.
Service tech recommended new modem (just bought 3.0 modem on recommended list less than a year ago), so I did that. Did not stop disconnects. Been in chat for 2 days with Xfinity with many promises of addressing local issues. Did not stop disconnects. I guess next I try new router and new ethernet card for PC. Just pouring money into an issue without any resolution. Although my internet has gotten faster, if anything the disconnects are more frequent. Going on about 3 weeks now. I even had a critical event this afternoon when I was not even home:
Thu Nov 07 17:20:58 2024
(Critical (3))
Started Unicast Maintenance Ranging - No Response received - T3 time-out;
Upstream and downstream power numbers seem OK. Is it normal to have upstream bonded channels 5-8 be "not locked?"
BruceW
Gold Problem Solver
•
26K Messages
22 days ago
Several downstream channels have out of spec SNR values (too low), and all the upstream channels have borderline power levels (too high). Network connection problems like this are often due to poor coax connections or damaged coax cable, usually in or near your home. Running the cable through a surge protector, a defective splitter, or too many splitters can cause signal problems as well. If there is an amplifier in the line make sure it's getting power.
If you want to troubleshoot this yourself, please see Internet Troubleshooting Tips. If you can't find the problem or you'd rather have Comcast take care of it and an employee does not respond to your message here, call them at the phone number on your bill or 1-800-Comcast, or use one of the options on https://www.xfinity.com/support/contact-us/. It's not likely they can fix the problem remotely. If not, insist they send a tech out to identify the cause and correct it.
If the tech finds bad coax, splitters, amplifiers, or connections in your home (even if Comcast originally supplied them) you'll probably have to pay for the visit (approx $100) unless you have their Service Protection Plan ( https://www.xfinity.com/support/articles/service-protection-plan, closed to customers that don't already have it). If the trouble is due to a faulty Comcast rental device or anything outside your home you shouldn't be charged.
Please be aware that there are 2 kinds of responses in this Forum: Replies and Comments. When you Comment on a post by scrolling down to "Comment on this post here...", I am notified of your response. But if you select Reply, I am NOT notified and may not be aware of your response.
0
XfinityRoberto
Official Employee
•
1.5K Messages
20 days ago
Hi there user_wslq80! Thank you so much for reaching out regarding your service issues you are having recently with your Internet service. You are in the right place and we are happy to take a look at your connection remotely and see if we can get it fixed.
Please send us a direct chat message with your full name and complete service address to “Xfinity Support”. To do so, click on the chat icon located at the top right of this forums page.
Here's the detailed steps to direct message us:
Let me know if you have any questions.
3
0