Need Help! Cable Modem (NetGear CM400) Started with 4 Upstreams Locked, Now Only One Locked
|Acquire Downstream Channel||585000000 Hz||Locked|
About 3pm CA time Sunday, July 3rd, Lost Internet Connectivity. Appears old SB modem, Lease from TWC, died. Replace it with NetGear CM400. Had TWC active CM400, all seemed fine. This morning, July 4th, internet was very slow, DNS failed queries.
Looking at modem (CM400) downstream seemed fine.
|Downstream Bonded Channels|
Upstream seemed fine, if power level was a bit high at 51/52 per locked upstream channel, but this was normal compared to past, and as noted above, internet connecitivity has been solid over the last 6 years, barring a few minor outages (external to home).
However, over the couse of the last 16 hours, CM400 has losted Upstream channels, 1 at time, ever few hours. Checked cables, checked splitters, etc. no unterminated connections, etc. But right now, only have 1 Upstream channel and power level is 57!
|Upstream Bonded Channels|
|Time Not Established||Critical (3)||No Ranging Response received - T3 time-out|
|Jul 5 03:31:34 2016||Warning (5)||MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1|
|Jul 5 03:32:14 2016||Critical (3)||No Ranging Response received - T3 time-out|
|Jul 4 19:32:27 2016||Warning (5)||MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1|
Error log is pretty clean given the capture above, but was getting a lot of T3 and T4 errors, lot of failure on upstream ranging errors, etc.
Figure I need to schedule a service call?
Solved! Go to Solution.
No, you need to get the extra splitters out of the line. Modem must be on no or the first 2 way if you have cable TV.
This looks like several and with open ports. Your downstream is low and the upstream is maxed out and out of range
After reboot this morning at about 5am (CA) time, was stable all day. just before lost of connectivity, had a bunch of T3 and T4 errors. After stable all day, this evening, bunch of T3 and T4 errors 8pm (CA) time. And had to reboot the modem again. All day had 3 upstreams locked, at 51/51 power level, but now after 8pm reboot of modem, back to 1 upstream at 57 power level! This is the same pattern, with slightly different time frames over the last 3 days.
Since I can't find any more splitters, can't seem to get downstream power level up, and can't seem to get upstream power level down, I am at a loss.
|Downstream Bonded Channels|
|Upstream Bonded Channels|
I have checked all cable terminations, all are connected or capped, with a proper termination cap (with center pin). So I am at a loss what to try next. I have an additional cable modem on order (different make and model) from the NetGear CM400, but I am not sure the CM400 is part of the issue here, I think the issue is in the wiring internal or external to the house. TWC stated that work was done Sunday near my address, and it was then, after almost perfect connectivity for over 5 years, I get this current situation? Kind of odd circumstance.
Error log... Had to reboot modem again, after posting above... and again the number of upstream channels that locked, changed again.
|Jul 5 18:57:11 2016||Warning (5)||MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1|
|Jul 5 19:06:24 2016||Critical (3)||No Ranging Response received - T3 time-out|
|Jul 5 19:08:29 2016||Critical (3)||Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out|
|Jul 5 19:08:40 2016||Critical (3)||No Ranging Response received - T3 time-out|
|Jul 6 03:08:48 2016||Warning (5)||MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1|
|Jul 6 03:08:58 2016||Critical (3)||No Ranging Response received - T3 time-out|
|Jul 5 19:09:14 2016||Warning (5)||MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1|
|Jul 5 19:10:14 2016||Warning (5)||Initializing Channel Timeout Expires - Time the CM can perform initial ranging on all upstream channels in the TCS has expired|
|Jul 5 19:10:14 2016||Warning (5)||TCS Partial Service|
|Jul 5 19:10:44 2016||Critical (3)||Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out|
|Jul 5 19:12:30 2016||Critical (3)||No Ranging Response received - T3 time-out|
|Jul 5 19:12:44 2016||Critical (3)|
Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out
Note change in upstream channels that locked... And power levels stepped back down again! This makes no sense (at least to me) that the upstream power level would be so inconsistent.
|Downstream Bonded Channels|
|Upstream Bonded Channels|
Get rid of ALL the splitters and call me in the morning. modem MUST BE on the first 2 way or no splitter. dvr/cable boxes AFTER that first splitter
Yours is not, especially if there's terminated ports...
Your levels are near/ or out of spec US needs to be below +50 dBmv and upstream should be closer to 0 dBmv
I think in past discussion, a misunderstanding has resulted, there has never been more than one splitter on the cable modem run/line. For over 6 years, was stable for the most part, except for the occasional T3 or T4 error, maybe 3 or 4 per year.
I have removed the single splitter as you suggested, and this improved the down stream powerlevels, they moved from 7-8 range to 2-3 range, so that is a significant improvement. But the upstream powerlevels remain unchanged for the most part, still 51-52 range per locked channel. Now, without the splitter I get 3 or 4 upstreams locked, where as with the splitter sometimes I got 1, most of the time 2 or 3 locked.
Acquire Downstream Channel 579000000 Hz Locked
Connectivity State Ok Operational
Boot State -- --
Configuration File -- --
Security Enabled BPI+
Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables UnCorrectables
1 Locked QAM 256 6 573000000 Hz -2.5 dBmV 37.3 dB 1 513
2 Locked QAM 256 7 579000000 Hz -2.5 dBmV 37.9 dB 51 604
3 Locked QAM 256 8 585000000 Hz -2.6 dBmV 38.2 dB 0 598
4 Locked QAM 256 9 591000000 Hz -2.8 dBmV 37.9 dB 0 1401
5 Locked QAM 256 10 597000000 Hz -3.1 dBmV 37.9 dB 13 586
6 Locked QAM 256 11 603000000 Hz -3.3 dBmV 38.2 dB 16 589
7 Locked QAM 256 12 609000000 Hz -3.5 dBmV 38.2 dB 10 595
8 Locked QAM 256 15 627000000 Hz -2.5 dBmV 37.9 dB 18 586
Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked TDMA 17 2560 Ksym/sec 18500000 Hz 51.0 dBmV
2 Locked ATDMA 18 5120 Ksym/sec 23300000 Hz 51.0 dBmV
3 Locked ATDMA 19 5120 Ksym/sec 30600000 Hz 51.0 dBmV
4 Locked ATDMA 20 2560 Ksym/sec 37000000 Hz 51.0 dBmV
The odd thing is, now, since July 3rd, I am getting many T3 and T4 errors, from 4:30 to 5:30am (CA) and 7:30pm to 8pm (CA). All day tends to be stable, all evening stable, except for the time frames noted above.
I have read other posts, that you have said, frequent T3 and T4 errors are an issue that is beyond what I can test, depending on where the issue is or what the issue is? Today alone, for the last hour, 10s of T3 and sometimes T4 errors! It took me over an hour just to get this reply posted given all the T3 resets.
Of course, I no longer have TV in the same room where I have the cable modem, and I also want that service, so what options do I have to get TV service? Since the single splitter is obvious contributing to the instability of the connectivity now, if not before.
You're going to need twc out, something is wrong before the splitter, either in the outside box or out on the pole.
All there should be in the outside box is a grounding block... Is it corroded?
Can you see if there's splitters up on the pole?
Yes, I will schedule a service call, I came the same conclusion, given the testing done. With no splitter, the T3 and T4 events are hammering my modem, every morning and late evening. Happened to day, from about 5:30am CA until 8pm (CA) was rock solid, then T3/T4 issues hit again, and now my powerlevels downstream jumped up, and I only have 1 upstream locked, get this... at 57! Not good!
The cable lines are underground trunk runs where I live. Just about 6 years ago, when I first moved it, I had the run from my house to the demark replaced, and that might be the issue again. The tech that came out swore that the line tested good, but he replaced it anyway, and all the issues disappeared.
Maybe the same scenario again this time. Thanks for the help and confirmation on testing. I also have the option of moving to FiOS, I had FiOS in my previous residence, and it was wonderful, I think it was down once in 4 years, if I call right.
Well, the TWC tech just left and it was an interesting experience. First, the tech was nice guy, he looked at the notes and data I had collected, which was a log of the cable modem errors, ping and trace-route reports, and record of power levels.
In summary here is what we, I say we, because I have worked in IT for over 30 years, and it is always nice when a tech shows up, and is open minded. This is not always the case, I know from experience, hey TWC, the guy that did my service call, was smart and responsive, nice.
1) The tech replaced the older AMP at the block, and adjusted the wiring to ensure the cable modem got the best signal possible.
2) He replaced the single splitter that was in place, with a TAP, ensuring the cable modem got the better leg.
3) The downstream levels changed over time randomly, from -4 to -6 at the low end and -8 to -10 at the upper end, not great but acceptable. He got the downsteam levels to about -5 across all 8 downstream channels.
4) The upstream levels where not great, with 1 upstream locked, it was 57! Not good. WIth 2, 3 or sometimes 4 locked upstream channels the level per channel was 50/51 or 51/52, still not good. After replace of the AMP and adjustment, the upstream channels were 38 to 43, with the first channel at 38, and last channel 43.
5) While the tech was onsight, he replaced the jumper leads, the short cables off the splitter to the cable modem, and the lead to the TV downstream AMP, yes I have a in-house downstream AMP to drive the 2 DTAs (TWC Digital Adapters) I have, this is needed due to the layout of the media room I have, he also checked the downstream AMP, and found it acceptable, given each leg off the downstream AMP is about -7, which fine for DTAs.
6) The tech found one of the short leads behind the splitter, the one to the in-house downstream AMP, had a bad connector, it was generating some signal errors, not significant, but the signal errors disappeared with the replacement of the bad connector. And since this issue was down the line from the splitter on the TV leg, the issue was not applicable to the cable modem.
Cable Block ------>TAP------>Cable Modem
`--------->In-House AMP----(replaced lead connector)----->DTA 1------>TV 1
`------------>DTA 2------>TV 2
7) The tech did validate/test the cable run from the block (house side) to the demark (street consolidation point).
Demark-----(Good)---->House Block---(Good)---->(Replaced)TWC AMP---(Good)--->In-House----(Good)--->TAP, etc. (See diagram above)
So the upstream powerlevels were improved. The minor issue on the DTA side legs was resolved, and the downstream in-house AMP, was ruled out as an issue. But... the random and significant number of T3 errors continued. While the tech was on sight, T3 errors reduced in volume, so the cable modem was not kicked offline, but about 30 minutes after the tech left, the massive T3 errors were back, and loss of connectivity via frequent cable modem reboots/resets resulted... again! Not good. Running the TWC speed check, was seeing some big up and down swings on the downward speed test, that was odd, that was new!
I called TWC support, worked my way past L1, L2, and got to L3 support... this is rare, as L3 support rarely is engaged via direct interaction with customers, but given the issue has been going on since the 3rd of the month, and today is the 17th.... lucky me. L3 support suggested I swap the cable modem, which I suspected was the next step and I had a SB6141 I had purchased the week before (from Amazon, white variant), so I swapped out the NetGear CM400 with the SB6141.
After about 10 minutes switching out the modems, the SB6141 was up and running. And for the last 2 hours or so no T3 errors. The downstream and upstream power levels continue to hold as noted above. And if the connectivity is stable say for 24 or 48 hours, I will update this post accordingly.
The one odd issue is I am not sure TWC is sending the right modem profile down to the modem, since I can't login to the SB6141 via the login page, but I can access the configuration information via the direct URLs only... this is an issue other TWC users have had with SB6141, it is fixed when TWC pushes down the right profile.
Bottom line, it appears the NetGear CM400 is just not a good fit for my TWC environment, it is on the approved list, but in my case, it seems to either not handle well T3/T4 or prone to T3/T4 errors? Whatever the case, improving the power levels alone was not sufficient.
Here is the firmware information:
Model Name: SB6141
Vendor Name: Motorola
Firmware Name: SB_KOMODO-18.104.22.168-SCM03-NOSH
Boot Version: PSPU-Boot(25CLK)(W) 22.214.171.124m5
Hardware Version: 8.0
Serial Number: [redacted]
Firmware Build Time: Jan 22 2015 14:31:03
Here the configuration information:
|Frequency Plan:||North American Standard/HRC/IRC|
|Custom Frequency Ordering:||Default|
|Upstream Channel ID:||18|
|Favorite Frequency (Hz)||573000000|
|DOCSIS MIMO||Honor MDD IP Mode|
|Modem's IP Mode||IPv4 Only|
Here is the error log during initial reboot, only one T3 error so far, normal for initial boot/setup:
|Jul 18 2016 02:58:49||6-Notice||D106.0||DHCP Renew - lease parameters time server-126.96.36.199;tftp file-?BEWGlysgPWYHQDAK1MNF@CtTDRTdrtsLIYWUmX+1EwNjMBIGwua15 modified;CM-MAC=20:3d:66:07:40:30;CMTS-MAC=00:01:5c:76:a8:60;CM-QOS=1.1;CM-VER=3.0;|
|Jul 18 2016 02:58:49||4-Error||D103.0||DHCP RENEW WARNING - Field invalid in response v4 option;CM-MAC=20:3d:66:07:40:30;CMTS-MAC=00:01:5c:76:a8:60;CM-QOS=1.1;CM-VER=3.0;|
|Jul 18 2016 02:30:47||6-Notice||I401.0||TLV-11 - unrecognized OID;CM-MAC=20:3d:66:07:40:30;CMTS-MAC=00:01:5c:76:a8:60;CM-QOS=1.1;CM-VER=3.0;|
|Jul 18 2016 02:30:47||5-Warning||Z00.0||MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=20:3d:66:07:40:30;CMTS-MAC=00:01:5c:76:a8:60;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=20:3d:66:07:40:30;CMTS-MAC=00:01:5c:76:a8:60;CM-QOS=1.1;CM-VER=3.0;|
|Jan 01 1970 00:00:15||6-Notice||N/A||Cable Modem Reboot from SNMP ;CM-MAC=20:3d:66:07:40:30;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.0;|
|Jul 18 2016 02:26:51||6-Notice||I401.0||TLV-11 - unrecognized OID;CM-MAC=20:3d:66:07:40:30;CMTS-MAC=00:01:5c:76:a8:60;CM-QOS=1.1;CM-VER=3.0;|
|Jul 18 2016 02:26:51||5-Warning||Z00.0||MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=20:3d:66:07:40:30;CMTS-MAC=00:01:5c:76:a8:60;CM-QOS=1.1;CM-VER=3.0;|
|Jan 01 1970 00:00:15||6-Notice||N/A||Cable Modem Reboot due to power reset ;CM-MAC=20:3d:66:07:40:30;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.0;|
Here is the curent power level information:
Downstream Bonding Channel Value
|Frequency||573000000 Hz||579000000 Hz||585000000 Hz||591000000 Hz||609000000 Hz||615000000 Hz||621000000 Hz||627000000 Hz|
|Signal to Noise Ratio||37 dB||38 dB||38 dB||38 dB||38 dB||38 dB||38 dB||38 dB|
|Power Level |
|-5 dBmV||-5 dBmV||-5 dBmV||-5 dBmV||-5 dBmV||-5 dBmV||-5 dBmV||-5 dBmV|
|Frequency||23300000 Hz||18500000 Hz||30600000 Hz||37000000 Hz|
|Ranging Service ID||9748||9748||9748||9748|
|Symbol Rate||5.120 Msym/sec||2.560 Msym/sec||5.120 Msym/sec||2.560 Msym/sec|
|Power Level||37 dBmV||35 dBmV||39 dBmV||40 dBmV|
|Upstream Modulation|| QPSK|
|Total Unerrored Codewords||129605530||129033180||129041367||129049641||129027035||129028909||129029990||129027987|
|Total Correctable Codewords||1||1||0||1||53||20||14||13|
Total Uncorrectable Codewords