nikki251's profile

New Poster

 • 

1 Message

Fri, Sep 11, 2020 2:00 PM

Intermittent connectivity problem: MDD Message Timeout, Started Unicast Maintenance Ranging ..

Please advise how to go about this - Symptom is that once or twice a day I lose internet connectivity. I can fix it by simply waiting a few minutes. But with working from home & school from home, that can be pretty disruptive with constant vpn disconnections. So I really want to fix this:

 

Here are the event logs from when it happened this afternoon:

Time Priority Description

Fri Sep 11 16:31:55 2020Warning (5)MDD message timeout;CM-MAC=e8:6d:52:7a:ab:4c;CMTS-MAC=00:01:5c:6b:f8:52;CM-QOS=1.1;CM-VER=3.0;
Fri Sep 11 15:00:37 2020Warning (5)MDD message timeout;CM-MAC=e8:6d:52:7a:ab:4c;CMTS-MAC=00:01:5c:6b:f8:52;CM-QOS=1.1;CM-VER=3.0;
Fri Sep 11 12:02:27 2020Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=e8:6d:52:7a:ab:4c;CMTS-MAC=00:01:5c:6b:f8:52;CM-QOS=1.1;CM-VER=3.0;
Fri Sep 11 12:02:27 2020Warning (5)MDD message timeout;CM-MAC=e8:6d:52:7a:ab:4c;CMTS-MAC=00:01:5c:6b:f8:52;CM-QOS=1.1;CM-VER=3.0;
Fri Sep 11 11:57:24 2020Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=e8:6d:52:7a:ab:4c;CMTS-MAC=00:01:5c:6b:f8:52;CM-QOS=1.1;CM-VER=3.0;
Fri Sep 11 11:57:24 2020Warning (5)MDD message timeout;CM-MAC=e8:6d:52:7a:ab:4c;CMTS-MAC=00:01:5c:6b:f8:52;CM-QOS=1.1;CM-VER=3.0;
Fri Sep 11 11:52:25 2020Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=e8:6d:52:7a:ab:4c;CMTS-MAC=00:01:5c:6b:f8:52;CM-QOS=1.1;CM-VER=3.0;
Fri Sep 11 11:52:25 2020Warning (5)MDD message timeout;CM-MAC=e8:6d:52:7a:ab:4c;CMTS-MAC=00:01:5c:6b:f8:52;CM-QOS=1.1;CM-VER=3.0;

 

Downstream Bonded Channels
ChannelLock StatusModulationChannel IDFrequencyPowerSNRCorrectedUncorrectables
1LockedQAM25633645000000 Hz1.1 dBmV39.6 dB00
2LockedQAM25634651000000 Hz0.4 dBmV39.5 dB00
3LockedQAM25635657000000 Hz0.5 dBmV39.0 dB00
4LockedQAM25636663000000 Hz-0.4 dBmV39.1 dB00
5LockedQAM25638669000000 Hz-0.6 dBmV39.0 dB57888104
6LockedQAM25639675000000 Hz-0.1 dBmV39.0 dB312616277772
7LockedQAM25640681000000 Hz-0.2 dBmV39.0 dB00
8LockedQAM25641687000000 Hz-0.9 dBmV38.6 dB00

 

Upstream Bonded Channels
ChannelLock StatusUS Channel TypeChannel IDSymbol RateFrequencyPower
1LockedATDMA75120 Ksym/sec23700000 Hz50.0 dBmV
2LockedATDMA55120 Ksym/sec36500000 Hz48.2 dBmV
3LockedATDMA65120 Ksym/sec30100000 Hz48.2 dBmV
4LockedATDMA85120 Ksym/sec17300000 Hz50.7 dBmV

Responses

EG

Expert

 • 

86.6K Messages

8 m ago

The upstream power is too high and it may be intermittently fluctuating even higher to out of spec levels. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of channels.

In a self troubleshooting effort to try to obtain better connectivity / more wiggle room, check to see if there are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured. Any splitters that remain should be high quality and cable rated for 5-1002 MHz, bi-directional, and no gold colored garbage types like GE, RadioShack, RCA, Philips, Leviton, Magnavox, and Rocketfish from big box stores like Home Depot, Lowes, Target, Wal-Mart etc. Splitters should be swapped with known to be good / new ones to test

If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two way splitter connected directly off of the drop from the street/pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed, and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then check for and clean off any corrosion / oxidation on the center wire and put them back together again, then perhaps it's best to book a tech visit to investigate and correct.

I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Mark the post as Best Answer!tick
bs92787

Regular Visitor

 • 

16 Messages

7 m ago

@nikki251 what type of modem are you using?  I was having similar issues I own an ARRIS SB6141 modem.  Comcast told me to contact the modem manufacturer only to find out that my upstream levels were "out of acceptable range."  Just curious what type of modem you have to look up what the acceptable range is with yours.  I just had a tech come out today he identified there was a 3 way splitter outside degrading my signal so he removed it.  Power levels are "ok" but he did say that there was another issue in the connection in the box outside so he has to log a maintenance ticket for them to come out and fix it.  Definitely sounds like an issue on Comcast end to me.

 

When I told the tech I was seeing the T3 timeout messages he said that always usually indicates a problem somewhere outside with their (Comcast) equipment/setup.

New to the Community?

Start Here