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Problem with new modem

NoNoBadPuppy
Contributor

Problem with new modem

For about two months, I have had a problem with my internet speeds being very slow.  I am on 200 Mbps plan. When I reboot my modem, I get 200+, but after a few minutes my speed will drop in the 30 to 35 Mbps range.  A technician came to my home, and replaced the cable coming from the pole to my house, and replaced all the coax in my home from the outlet to my modem.  That did not help.  I have made repeated calls to support, and invariably, they send a signal to reboot my modem, which resets speed (albeit temporarily) to roughly 200 Mbps.  They tell me everything is fine...not to worry...etc.  I tell them it will drop, and they 'assure' me that everything is working and tell me not to worry.  I hang up, wait a few minutes, and call back when my speeds drop to 30-35.  Wash, rinse, repeat.  Today I replaced my modem with a new Motorola SB8200.  It is a DOCSIS 3.1 modem, and I bought it because it is recommended for xfinity and is more stable than my older DOCSIS 3.1 netgear modem.  I had to call to activate.  Once activated, I told the woman who activated it that it activated as a DOCSIS 3.0.  She sent a signal that re-provisioned the modem, which took several times, and once active, it was again DOCSIS 3.0.  The woman told me it would take 24 hours for the modem to connect at DOCSIS 3.1. I fail to understand why this would be so.  How do I get my Arris SB8200 to connect as a DOCSIS 3.1 modem?  Thank you for your time in this matter. 

EG
Expert

Re: Problem with new modem


@NoNoBadPuppy wrote:

Once activated, I told the woman who activated it that it activated as a DOCSIS 3.0.  She sent a signal that re-provisioned the modem, which took several times, and once active, it was again DOCSIS 3.0.


Please describe how you determined this ?



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NoNoBadPuppy
Contributor

Re: Problem with new modem

The status light on the modem.  If the downstream is DOCSIS 3.0, the light is green.  If it is a DOCSIS 3.1 bonded stream, then the light would be blue.  On the modem, the light is green.

EG
Expert

Re: Problem with new modem

Yep, o/k.

 

What do the modem's signal stats look like ? Try getting them here; http://192.168.100.1

Please post the *Downstream Power Level*, the *Upstream Power Level*, and the *SNR* (Signal to Noise Ratio) numbers.




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NoNoBadPuppy
Contributor

Re: Problem with new modem

Sorry for the delay.  My wife had surgery two days ago, and we've been busy keeping her comfortable.

 

Here are the numbers from the modem.  They were measured after a hard reset of the modem, and with only a desktop computer hardwired into the active port.

 

Working with a technician at Arris. I was told that my upstream power levels are below what is considered adequate, which the tech stated was abouve 45 dBm.

 

There are no DOCSIS 3.1 channels bonded. I am on a 200 Mbps tier, so I am wondering if DOCSIS 3.1 is simply not available on my package. 

 

When the modem is rebooted, I get between 195 - 230 Mbps download measued by wired connection, but it will drop incrementally over time to as low as 30Mbs.  I have had the line from the pole to the house replaced, all coac in the home replaced, replaced the router and modem.  I have effectively eliminated all possible failure points in my home.   I wish that the cause of the problem could be found.  Does xFinity throttle home users?  I am on the standare 1.2 TB data cap, but never come anywhere near the limit, and have never gone over. 

Startup Procedure

Procedure                                                                      Status                                                 Comment

Acquire Downstream Channel                                           573000000 Hz                                       Locked

Connectivity State                                                             OK                                                      Operational

Boot State                                                                        OK                                                      Operational

Configuration File                                                            OK

Security                                                                           Enabled                                               BPI+

DOCSIS Network Access Enabled                                      Allowed

Downstream Bonded Channels

Channel ID

Lock Status

Modulation

Frequency

Power

SNR/MER

Corrected

Uncorrectables

41

Locked

QAM256

573000000 Hz

-7.0 dBmV

39.0 dB

0

0

13

Locked

QAM256

399000000 Hz

-6.0 dBmV

39.6 dB

0

0

14

Locked

QAM256

405000000 Hz

-2.7 dBmV

40.6 dB

0

0

15

Locked

QAM256

411000000 Hz

-1.9 dBmV

40.7 dB

0

0

16

Locked

QAM256

417000000 Hz

-1.6 dBmV

40.7 dB

0

0

17

Locked

QAM256

423000000 Hz

-2.1 dBmV

40.8 dB

0

0

18

Locked

QAM256

429000000 Hz

-2.9 dBmV

40.5 dB

0

0

19

Locked

QAM256

435000000 Hz

-2.4 dBmV

40.7 dB

0

0

20

Locked

QAM256

441000000 Hz

-0.9 dBmV

40.9 dB

0

0

21

Locked

QAM256

447000000 Hz

-0.8 dBmV

41.0 dB

0

0

22

Locked

QAM256

453000000 Hz

-0.8 dBmV

40.9 dB

0

0

23

Locked

QAM256

459000000 Hz

-0.9 dBmV

41.0 dB

0

0

24

Locked

QAM256

465000000 Hz

-1.4 dBmV

39.0 dB

0

0

25

Locked

QAM256

471000000 Hz

-2.1 dBmV

40.7 dB

0

0

26

Locked

QAM256

477000000 Hz

-2.0 dBmV

40.7 dB

0

0

27

Locked

QAM256

483000000 Hz

-2.3 dBmV

40.6 dB

0

0

28

Locked

QAM256

489000000 Hz

-2.9 dBmV

40.4 dB

0

0

29

Locked

QAM256

495000000 Hz

-3.3 dBmV

40.4 dB

0

0

30

Locked

QAM256

501000000 Hz

-3.4 dBmV

40.3 dB

0

0

 

Status

 

 

 

https://192.168.100.1/cmconnectionstatus.html

31

Locked

QAM256

507000000 Hz           -4.2 dBmV                     40.0 dB

0

0

32

Locked

QAM256

513000000 Hz           -4.4 dBmV                     39.9 dB

0

0

33

Locked

QAM256

519000000 Hz           -5.2 dBmV                     39.8 dB

0

0

34

Locked

QAM256

525000000 Hz           -5.7 dBmV                     39.6 dB

0

0

35

Locked

QAM256

531000000 Hz           -4.9 dBmV                     39.9 dB

0

0

36

Locked

QAM256

537000000 Hz           -4.9 dBmV                     39.9 dB

0

0

37

Locked

QAM256

543000000 Hz           -7.6 dBmV                     38.5 dB

0

0

38

Locked

QAM256

555000000 Hz           -8.1 dBmV                     38.3 dB

0

0

39

Locked

QAM256

561000000 Hz           -7.9 dBmV                     38.6 dB

0

0

40

Locked

QAM256

567000000 Hz           -5.7 dBmV                     39.2 dB

0

0

42

Locked

QAM256

579000000 Hz           -11.4 dBmV                     36.3 dB

0

0

43

Locked

QAM256

585000000 Hz           -11.7 dBmV                     35.9 dB

0

0

44

Locked

QAM256

591000000 Hz           -11.7 dBmV                     36.2 dB

0

0

 

 

Upstream Bonded Channels

 

 

Channel

Channel ID

Lock Status

US Channel Type                                                                   Frequency

Width

Power

1

1

Locked

SC-QAM Upstream                                                                   35600000 Hz

6400000 Hz

43.0 dBmV

2

2

Locked

SC-QAM Upstream                                                                   29200000 Hz

6400000 Hz

42.0 dBmV

3

3

Locked

SC-QAM Upstream                                                                   22800000 Hz

6400000 Hz

42.0 dBmV

4

4

Locked

SC-QAM Upstream                                                                   16400000 Hz

6400000 Hz

42.0 dBm

EG
Expert

Re: Problem with new modem

The downstream power levels are on the low / weak side and are out of spec on some of the channels. 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.



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NoNoBadPuppy
Contributor

Re: Problem with new modem

Thank you.  You are confirming what the Arris tech told me when we looked at the signals with them.

THe problem I face now is that when I call comcast support, they have me go through the routine of rebooting the router, and as stated immediately after reboot signal levels are good and I get good speed.  At that point, they tell me 'everything looks good' and ends it.  I cannot get anyone to inderstand that after replacingn all lines inside and out, replacing router and modem, I have eliminated any potentional problems in my home.  They will not send out anyone to actually look at the signal strength. I called about this situation, and they told me they will not send out a technician; that I need to buy their modem (after I have already bought a new modem, a new router, and had all the lines from the treet to my home and all the cables and spliiters in my house replace by the same tech.  I have never been so frustrated with a situation as I am with this one.

 

EG
Expert

Re: Problem with new modem

Looks like your only recourse is to keep leaning on them to send a tech out.

 

Bear in mind that if the premises facing techs can not find or fix a problem at your home, it is they who are responsible for escalating it to their line / network / maintenance dept. techs. The problem may lie beyond your home in the local neighborhood infrastructure somewhere but it is their S.O.P. to start at the home.
Good luck !



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NoNoBadPuppy
Contributor

Re: Problem with new modem

I told the rep that 'we won't send out a technician" was not an option.  I told him that telling me I had to buy their x6 modem was not an option.  I told him that the boilerplate they read from about rebooting, etc, was no longer an option.  I told the rep I wanted to speak to his manager.  Manager refused to speak to me.  Rep offered to send me over to 'retention'.  I told him that was not an option.  I told him that after weeks of this back and forth, the only option was to have my case escalated.  His manager finally agreed, but only because they didn't want to have to deal with me anymore.  I was transferred to a technician in the U.S., named Kaylee.  She reviewed my case history, and agreed that it was time to send out a higher level technician.  I have an appointment tomorrow between 8 and 10 am.  The tech will check the line outside, and if necessary, install an amplifier.  He may have to come inside to verify signal levels at the modem, which I would assume would be a given.  I am hoping it goes well.

 

Thank you for your time in this regard. I have not been this frustrated in dealing with an entity is a very, very long time.  If Comcast were not the only provider in my area, I would have been long gone.  The only other option is satellite at 3 Mbps download and 128k (!) upload.  Yikes!

 

 

EG
Expert

Re: Problem with new modem

My pleasure ! Good luck with it ! Please post back with how things turn out.



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NoNoBadPuppy
Contributor

Re: Problem with new modem

Technician just left.  He found and corrected two issued, both at the drop on the pole.  First was a loose connection on that end of the line that goes to our home.  The second one should have been corrected by previous tech visits but wasn't.  The house next door to us, which shared that same drop, burned down two years ago.  There was still a length of coax hanging from the drop; it had been cut (so was not properly terminated), and was just hanging down.  He romoved that, and made sure all connections involved were tight and terminated properly.  Signal looks good now.  Hope it stays that way.  I also asked about DOCSIS 3.1, and it is not yet available in my area (i am rural and remote).  We are scheduled to have the necessary upgrades to infrastructure done soon, and then it will be avaialble,

 

Once again, thank you for you time and help. 

 

NoNoBadPuppy
Contributor

Re: Problem with new modem

I wonder if I amy impose upon you once again.  After 24 hours, my upstream and downstream have been stable, and my speeds have remained where they should be, but there are a lot of errors in the event log.  I made copies of the power levels and the errors before and after a reboot today.  I will post the first page of the error log below; can you please tell me if anything there requires attention?  Thank you. 

EG
Expert

Re: Problem with new modem

Bottom line. If you are not actually experiencing any connection speed problems then don't sweat the log entries.



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