I am having (for the past 2 months) regular (daily sometimes more than once a day) disconnects. These last about 6-7 minutes before connection is re-established. I had an original COMCAST TG modem, and it still did the same. I switched to an Arris SB6183, but the problem is still there. Some days there are no disconnects. Others, many. I feel it is likely a Comcast server problem whichever modem set I am connecting to at their end.
I'm technically minded and have loaded a monitoring script onto my router and it confirms loss of connection, and then waits til it returns - I also monitor externally through a "ping" type service from panopta. That's how I know its around 6 minutes.
Given I have switched modems and also routers, I am not sure how to fix this or even pin point the issue. I've seen on here that helpers usually request the channel dump from the modem... so here it is, along with the event log showing what the modem thinks happened during two such instances this morning - any help gratefully received!
EDIT: read the connection pin post - no, have not had any Comcast visit and have not reported it yet. Lights on modem all steady (two blue middle - the bonded channels, two green outer, the power and "internet" ones). After ~5 mins of failed connection, the modem restarts the WAN connection attempt and all lights flash in sequence as if powered on.
|Standard Specification Compliant||DOCSIS 3.0|
|Cable Modem MAC Address||XXXXXXXX|
|Sun Dec 24 10:33:13 2017||Warning (5)||Dynamic Range Window violation|
|Time Not Established||Notice (6)||Honoring MDD; IP provisioning mode = IPv6|
|Sun Dec 24 10:32:13 2017||Critical (3)||Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=74:ea:e8:XXXXXX;CMTS-MAC=00:01:5c:XXXXXX;CM-QOS=1.1;CM-VER=3.0;|
|Sun Dec 24 10:27:53 2017||Critical (3)||Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=74:ea:e8:XXXXXX;CMTS-MAC=00:01:5c:XXXXXX;CM-QOS=1.1;CM-VER=3.0;|
|Time Not Established||Critical (3)||No Ranging Response received - T3 time-out|
|Sun Dec 24 10:11:44 2017||Critical (3)||Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=74:ea:e8:XXXXXX;CMTS-MAC=00:01:5c:XXXXXX;CM-QOS=1.1;CM-VER=3.0;|
|Sun Dec 24 10:07:24 2017||Critical (3)||Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=74:ea:e8:XXXXXX;CMTS-MAC=00:01:5c:XXXXXX;CM-QOS=1.1;CM-VER=3.0;|
|Acquire Downstream Channel||Locked|
|DOCSIS Network Access Enabled||Allowed|
|Downstream Bonded Channels|
|Channel||Lock Status||Modulation||Channel ID||Frequency||Power||SNR||Corrected||Uncorrectables|
|1||Locked||QAM256||9||663000000 Hz||6.0 dBmV||41.6 dB||12||69|
|2||Locked||QAM256||1||615000000 Hz||6.5 dBmV||42.3 dB||0||0|
|3||Locked||QAM256||2||621000000 Hz||6.5 dBmV||42.2 dB||0||0|
|4||Locked||QAM256||3||627000000 Hz||6.3 dBmV||42.1 dB||0||0|
|5||Locked||QAM256||4||633000000 Hz||6.3 dBmV||41.9 dB||0||0|
|6||Locked||QAM256||5||639000000 Hz||6.3 dBmV||40.3 dB||0||0|
|7||Locked||QAM256||6||645000000 Hz||6.2 dBmV||41.8 dB||0||0|
|8||Locked||QAM256||7||651000000 Hz||6.2 dBmV||41.8 dB||0||0|
|9||Locked||QAM256||8||657000000 Hz||6.1 dBmV||41.6 dB||0||0|
|10||Locked||QAM256||10||669000000 Hz||6.0 dBmV||41.5 dB||0||0|
|11||Locked||QAM256||11||675000000 Hz||6.0 dBmV||40.9 dB||0||0|
|12||Locked||QAM256||12||681000000 Hz||5.6 dBmV||41.0 dB||0||0|
|13||Locked||QAM256||13||687000000 Hz||5.8 dBmV||41.0 dB||0||0|
|14||Locked||QAM256||14||693000000 Hz||5.7 dBmV||41.1 dB||0||0|
|15||Locked||QAM256||15||699000000 Hz||6.1 dBmV||41.3 dB||0||0|
|16||Locked||QAM256||21||735000000 Hz||5.7 dBmV||40.6 dB||0||0|
|Upstream Bonded Channels|
|Channel||Lock Status||US Channel Type||Channel ID||Symbol Rate||Frequency||Power|
|1||Locked||ATDMA||14||5120 Ksym/sec||29400000 Hz||39.8 dBmV|
|2||Locked||ATDMA||13||5120 Ksym/sec||35800000 Hz||39.5 dBmV|
|3||Locked||ATDMA||15||5120 Ksym/sec||23000000 Hz||40.0 dBmV|
Solved! Go to Solution.
The stats as read at the modem level at that moment in time were o/k but there are three additional signal stats which can't be read by the modem. They can only be read from their end by them polling the CMTS (Cable Modem Termination System) at the local headend facility.
They are the "Upstream Rx Power" (Upstream Receive Power Level), the "Upstream SNR Ch." (Upstream Signal To Noise Ratio), and the "Upstream ICFR" (In Channel Frequency Response). These are as equally important in diagnosing connectivity issues as are the modem's stats.
You can call in and ask what these figures are. The Upstream Receive Power Level should fall within the range of -2dB to +2dB with 0dB being in the middle and perfect.
The Upstream SNR should be least 31dB, and the higher it is the better.
The ICFR should be no higher than 2 dB.
You could have an intermittent noise ingress issue in only the upstream channel(s) / return path only somewhere.
They will be able to see whether or not everything is in the green zone and also see a history plot for the modem.
Thanks for the quick response. I called COMCAST and after being cut off as they "reprovisioned" my modem, I spoke with someone who checked the headend details. Apparently my SNR is 33.1 and the Upstream power level is exactly 0dB. They could not find the ICFR figure.
They agreed the modem was disconnecting, but their only response was "we can send a tech out" ... at my cost... to diagnose the problem, which may be water in a chewed cable (had a wrecked cable a few years back, so that is a possibility) or a myriad of other things I don't think are my fault - I notice the cable from the box to the pole was not buried well - I reburied it some time back, but the problem already existed at that time. I have had splitter problems a couple years back but they came out and fixed it. I don't have any other internet drops or splitters in the house – it’s a single coax from the box to the modem. COMCAST cabled that up in November.
My issue with agreeing to a tech is, the problem may well not exhibit when he is here (most unlikely) and they may well check all sorts and find nothing wrong, or something wrong, and "fix it" and a few days later the same thing happens and I am no further forward but $60+ down with no recourse from COMCAST - if it’s my equipment, I accept the problem is mine. If it’s from the box to the pole onwards, I don't understand why it's my problem or at my cost?
I will monitor the line over the next couple weeks and see. Advice welcome.
If the problem turns out to be on their side of the grounding block / demarcation point outward, and not on your premises side, there should not be a charge. Good luck !
After monitoring it for a few days, and seeing it break connection as before, up to 10 times a day, I called and scheduled a tech as described.
Two days after I called to schedule, the problem has disappeared completely. I get zero disconnects 24x7. I see a few issues on correctables/uncorrectables on the modem (a few hundred, over three days) but considering the number of packets flowing, I think that is irrelevent and its certainly not changing or getting worse.
Frustrating, as I should now probably cancel that tech call as they'll find nothing wrong and I'll be up for the $60 charge. Maybe somethng changed for the better at the head end... and nobody mentioned it.
Hello @doyle250. It's possible we had network repairs/maintenance completed recently. If you'd like to check, or need help cancelling a technician visit, I can help. If so, please send me a private message and include your full name, service address, and account number so I can access your account.
Violation post Removed as per the Forum Guidelines (deliberate forum language filter bypasses). These can be reviewed here: http://forums.xfinity.com/t5/Forum-Community/Forums-Policy-and-Guidelines/td-p/2618379
I don't seem to be able to add this reply to the existing thread... clicking "reply" burron at end of thread does nothing. In any browser...
The problem was solved by a tech visit. The reason for the multiple disconnects (in my case) was the power level was too high at the house...because the power level was too high at the pole... because whoever adjusted it further up the street on a previous unconnected visit did not balance the remaining poles as they should have, so when they amped up someone elses feed, mine went ballistic. We are on a street and I am about 6th in line after the main pole with the primary amp (according to the tech). He called it in, and a cherry picker tech came out and adjusted mine and the neighbours. Levels back down to normal and no disconnects. "lazy" was his assessment. PITA was mine. But fixed nonetheless.