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Regular Connection Issues - Modem? Router?

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Regular Visitor

Regular Connection Issues - Modem? Router?

I'm experiencing daily connection issues; wondering if my modem, router, or connection is the problem. Using an 802.11n Apple Airport Express running 7.6.9 and Motorola SURFboard SB6121 (running SB_KOMODO-1.0.6.16-SCM00-NOSH for what it's worth). I have a 150Mbps plan.

 

On mydeviceinfo.xfinity.com it says my modem is not supported, which confuses me because it does not say that here: https://mydeviceinfo.xfinity.com/device/arris-sb6121-365 Do you think this could be the problem? And why would this modem be EOL even though it's specifications support my speeds? 

 

I don't experience any error (or other-than-ordinary) lights on either the modem or router, and the internet just stops responding. A simple modem + router restart always does the trick. 

 

Perhaps unrelated, but if I try uploading content (like a couple hundred photos) to the cloud, my internet comes to a screeching halt: can't load websites, stream TV, send an iMessage... nothing. I understand that uploading uses a lot of bandwitdth, but it shouldn't kill my internet completely, right? Perhaps related? 

 

Thank you so much for any thoughts on this. I haven't had much luck talking to Comcast over the phone, and a tech has not visited. I'm not completely computer illiterate, but I don't really know where to start with this one.

 

REQUESTED INFO: 

Time Priority Code Message
Mar 17 2018 13:45:30 3-Critical R02.0 No Ranging Response received - T3 time-out;CM-MAC=6c:ca:08:89:51:a1;CMTS-MAC=00:01:5c:63:ec:64;CM-QOS=1.1;CM-VER=3.0;
Mar 17 2018 13:45:29 5-Warning Z00.0 MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=6c:ca:08:89:51:a1;CMTS-MAC=00:01:5c:63:ec:64;CM-QOS=1.1;CM-VER=3.0;
Jan 01 1970 00:00:20 3-Critical R02.0 No Ranging Response received - T3 time-out;CM-MAC=6c:ca:08:89:51:a1;CMTS-MAC=00:01:5c:63:ec:64;CM-QOS=1.1;CM-VER=3.0;
Jan 01 1970 00:00:13 6-Notice N/A Cable Modem Reboot due to power reset ;CM-MAC=6c:ca:08:89:51:a1;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.0;
Mar 16 2018 21:01:42 3-Critical R02.0 No Ranging Response received - T3 time-out;CM-MAC=6c:ca:08:89:51:a1;CMTS-MAC=00:01:5c:63:ec:64;CM-QOS=1.1;CM-VER=3.0;
Mar 16 2018 21:01:41 5-Warning Z00.0 MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=6c:ca:08:89:51:a1;CMTS-MAC=00:01:5c:63:ec:64;CM-QOS=1.1;CM-VER=3.0;
Jan 01 1970 00:00:18 3-Critical R02.0 No Ranging Response received - T3 time-out;CM-MAC=6c:ca:08:89:51:a1;CMTS-MAC=00:01:5c:63:ec:64;CM-QOS=1.1;CM-VER=3.0;
Jan 01 1970 00:00:13 6-Notice N/A Cable Modem Reboot due to power reset ;CM-MAC=6c:ca:08:89:51:a1;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.0;
Mar 16 2018 19:59:16 3-Critical R02.0 No Ranging Response received - T3 time-out;CM-MAC=6c:ca:08:89:51:a1;CMTS-MAC=00:01:5c:63:ec:64;CM-QOS=1.1;CM-VER=3.0;
Mar 16 2018 19:59:15 5-Warning Z00.0 MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=6c:ca:08:89:51:a1;CMTS-MAC=00:01:5c:63:ec:64;CM-QOS=1.1;CM-VER=3.0;
Jan 01 1970 00:00:35 3-Critical R02.0 No Ranging Response received - T3 time-out;CM-MAC=6c:ca:08:89:51:a1;CMTS-MAC=00:01:5c:63:ec:64;CM-QOS=1.1;CM-VER=3.0;
Jan 01 1970 00:00:13 6-Notice N/A Cable Modem Reboot due to power reset ;CM-MAC=6c:ca:08:89:51:a1;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.0;
Mar 12 2018 19:24:42 5-Warning Z00.0 MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=6c:ca:08:89:51:a1;CMTS-MAC=00:01:5c:63:ec:64;CM-QOS=1.1;CM-VER=3.0;
Jan 01 1970 00:00:19 3-Critical R02.0 No Ranging Response received - T3 time-out;CM-MAC=6c:ca:08:89:51:a1;CMTS-MAC=00:01:5c:63:ec:64;CM-QOS=1.1;CM-VER=3.0;
Jan 01 1970 00:00:13 6-Notice N/A Cable Modem Reboot due to power reset ;CM-MAC=6c:ca:08:89:51:a1;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.0;
Mar 01 2018 21:11:33 5-Warning Z00.0 MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=6c:ca:08:89:51:a1;CMTS-MAC=00:01:5c:63:ec:64;CM-QOS=1.1;CM-VER=3.0;
Jan 01 1970 00:00:20 3-Critical R02.0 No Ranging Response received - T3 time-out;CM-MAC=6c:ca:08:89:51:a1;CMTS-MAC=00:01:5c:63:ec:64;CM-QOS=1.1;CM-VER=3.0;
Jan 01 1970 00:00:13 6-Notice N/A Cable Modem Reboot due to power reset ;CM-MAC=6c:ca:08:89:51:a1;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.0;
Feb 24 2018 20:02:27 5-Warning Z00.0 MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=6c:ca:08:89:51:a1;CMTS-MAC=00:01:5c:63:ec:64;CM-QOS=1.1;CM-VER=3.0;
Jan 01 1970 00:00:19 3-Critical R02.0 No Ranging Response received - T3 time-out;CM-MAC=6c:ca:08:89:51:a1;CMTS-MAC=00:01:5c:63:ec:64;CM-QOS=1.1;CM-VER=3.0;

 

 

Downstream Bonding Channel Value
Channel ID 15  16  21  22 
Frequency 597000000 Hz  603000000 Hz  633000000 Hz  639000000 Hz 
Signal to Noise Ratio 37 dB  37 dB  37 dB  38 dB 
Downstream Modulation QAM256  QAM256  QAM256  QAM256 
Power Level
The Downstream Power Level reading is a snapshot taken at the time this page was requested. Please Reload/Refresh this Page for a new reading
12 dBmV   12 dBmV   12 dBmV   13 dBmV  

 

Upstream Bonding Channel Value
Channel ID 28  25  26  27 
Frequency 38700000 Hz  19300000 Hz  25700000 Hz  32300000 Hz 
Ranging Service ID 9092  9092  9092  9092 
Symbol Rate 5.120 Msym/sec  5.120 Msym/sec  5.120 Msym/sec  5.120 Msym/sec 
Power Level 42 dBmV  40 dBmV  41 dBmV  41 dBmV 
Upstream Modulation [3] QPSK
[3] 64QAM
 
[3] QPSK
[3] 64QAM
 
[3] QPSK
[3] 64QAM
 
[3] QPSK
[3] 64QAM
 
Ranging Status Success  Success  Success  Success 
Expert

Re: Regular Connection Issues - Modem? Router?

It's definitely time to upgrade your modem, it's not capable of supporting your current speed tier. 

You downstream signals are also too high. If you have an amplifier, take it out. Otherwise, you can lower the signal with an attenuator. You can use a splitter temporarily to reduce the signal.

 

Let us know if you need more help! 

 


I am not an employee.
Regular Visitor

Re: Regular Connection Issues - Modem? Router?

Thank you so much for your helpful response. I’ll try to pick up an attenuator later today.

In the meantime, I am a bit baffled by the modem situation. You’re right, it does say my modem is no longer supported when I login, but I’m still picking up mixed messages from Comcast. There’s currently a pinned article (“SB6121/6141 End of Life Details”) from a Comcast employee saying that owned SB6121s are still supported. I know that article is over 2 years old, but it seems to be the most current info available.

Ignoring speed concerns, is the modem likely to be the cause of my connection issues? I’d just hate to spend $100+ on a new modem only to realize it wasn’t the problem. I’m actually fairly content with my download speeds... unless my upload problems are related to my modem EOL? Is there any way for me to know?

Thanks again!
Expert

Re: Regular Connection Issues - Modem? Router?

Your modem is not EOL yet since it's a retail version. Its primary limitation is that it does not support enough channels for higher speed tiers. If you are happy with your speeds and the modem is still functional, you don't need to replace it. Even after Comcast makes it EOL, you can keep using it. It simply means that it is no longer supported. 

 

I wouldn't be surprised if the modem is dying since it's pretty old, but the first step would be to knock those power levels down. I'd knock it down 6 or 7 dB; either an attenuator (the right way) or a 4-way splitter (a bit of a band-aid). If that doesn't work for you, consider renting a modem from Comcast for a month to see if a new modem resolves your issue.


I am not an employee.
Regular Visitor

Re: Regular Connection Issues - Modem? Router?

Thanks again for your help! My attenuator arrived today, and signal levels are looking better (I think). We'll see if it does the trick.

 

 

Downstream Bonding Channel Value
Channel ID 15  17  19  20 
Frequency 597000000 Hz  609000000 Hz  621000000 Hz  627000000 Hz 
Signal to Noise Ratio 37 dB  38 dB  38 dB  38 dB 
Downstream Modulation QAM256  QAM256  QAM256  QAM256 
Power Level
The Downstream Power Level reading is a snapshot taken at the time this page was requested. Please Reload/Refresh this Page for a new reading
6 dBmV   6 dBmV   7 dBmV   7 dBmV  

 

Upstream Bonding Channel Value
Channel ID 28  25  26  27 
Frequency 38700000 Hz  19300000 Hz  25700000 Hz  32300000 Hz 
Ranging Service ID 11146  11146  11146  11146 
Symbol Rate 5.120 Msym/sec  5.120 Msym/sec  5.120 Msym/sec  5.120 Msym/sec 
Power Level 47 dBmV  46 dBmV  47 dBmV  47 dBmV 
Upstream Modulation [3] QPSK
[3] 64QAM
 
[3] QPSK
[3] 64QAM
 
[3] QPSK
[3] 64QAM
 
[3] QPSK
[3] 64QAM
 
Ranging Status Success  Success  Success  Success