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Very slow upload speed

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Frequent Visitor

Very slow upload speed

My problem seems identical to the one described in this post: https://forums.xfinity.com/t5/Your-Home-Network/Extremely-slow-upload-speeds/td-p/3059871

 

I have the 300/25 service. My only issue is that the upload speed is consistently <40% of what is advertised; consistently in the 6-8 Mbps range when I typically use the internet. It's 10am on a workday, when I'd normally be at work, and I'm seeing 11 Mbps for the first time ever; reported by Speedtest.Xfinity.com and Fast.com. This is a real problem, as I want to stream video with my calls to friends and family in the evenings but ~7Mbps is a bottleneck. I recently upgraded form the XB3 (TG1682G) modem/router to a Netgear CM1150V for other reasons and the upload issue persists.

 

 

20191205 Bonded Channels from CM1150V.JPG

 

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Gold Problem Solver

Re: Very slow upload speed

The image you posted isn't visible. It looks like this:

 

HfImgPlcHldr.gif

This is probably because you are a new poster and the image requires moderator approval. That could take a while. If you don't want to wait you could upload the image to a file sharing site and post a link to it here, or post text instead of an image.

 

Meanwhile please see Connection Troubleshooting Tips and Information Requested for Connection-Related Posts.

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Frequent Visitor

Re: Very slow upload speed

Thank you for that information, Bruce. I noticed that when I posted, but had to leave. Now it appears to be working. I will start reading through the troubleshooting link you you sent.

 

  • Post your modem’s error logs. 
    • See below.
    • [REDACTED] = CM1150V
    • [REDACTED_2] = Local Comcast
  • Post the make and model of your modem/gateway.
    • Netgear CM1150V
  • Post the make and model of your router if you have one.
    • Issue resides when connected directly to the modem, even after a fresh restart.
  • Let us know if you contacted Comcast or had a tech visit.
    • Not yet.
  • Let us know what the lights on your modem are doing when you are having problems.
    • Power, Up link, Down link, WWW, both phone line lights are solid green. LAN light flickers green, as usual.

 

Error Logs

"Event Logs" per Netgear Genie interface:

Time

Priority

Description

Thu Dec 05 14:53:43 2019

Warning (5)

Dynamic Range Window violation

Thu Dec 05 14:53:43 2019

Warning (5)

RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=[REDACTED];CMTS-MAC=[REDACTED_2];CM-QOS=1.1;CM-VER=3.1;

Thu Dec 05 14:45:44 2019

Warning (5)

Dynamic Range Window violation

Thu Dec 05 14:45:44 2019

Warning (5)

RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=[REDACTED];CMTS-MAC=[REDACTED_2];CM-QOS=1.1;CM-VER=3.1;

Thu Dec 05 12:46:54 2019

Warning (5)

Dynamic Range Window violation

Thu Dec 05 12:46:54 2019

Warning (5)

RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=[REDACTED];CMTS-MAC=[REDACTED_2];CM-QOS=1.1;CM-VER=3.1;

Thu Dec 05 10:13:07 2019

Warning (5)

Dynamic Range Window violation

Thu Dec 05 10:13:07 2019

Warning (5)

RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=[REDACTED];CMTS-MAC=[REDACTED_2];CM-QOS=1.1;CM-VER=3.1;

Thu Dec 05 09:42:50 2019

Warning (5)

Dynamic Range Window violation

Thu Dec 05 09:42:50 2019

Warning (5)

RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=[REDACTED];CMTS-MAC=[REDACTED_2];CM-QOS=1.1;CM-VER=3.1;

Thu Dec 05 09:42:50 2019

Warning (5)

Dynamic Range Window violation

Thu Dec 05 09:42:50 2019

Warning (5)

RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=[REDACTED];CMTS-MAC=[REDACTED_2];CM-QOS=1.1;CM-VER=3.1;

Thu Dec 05 08:53:14 2019

Warning (5)

Dynamic Range Window violation

Thu Dec 05 08:53:14 2019

Warning (5)

RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=[REDACTED];CMTS-MAC=[REDACTED_2];CM-QOS=1.1;CM-VER=3.1;

Thu Dec 05 08:15:18 2019

Warning (5)

Dynamic Range Window violation

Thu Dec 05 08:15:18 2019

Warning (5)

RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=[REDACTED];CMTS-MAC=[REDACTED_2];CM-QOS=1.1;CM-VER=3.1;

Thu Dec 05 06:12:28 2019

Warning (5)

Dynamic Range Window violation

Thu Dec 05 06:12:28 2019

Warning (5)

RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=[REDACTED];CMTS-MAC=[REDACTED_2];CM-QOS=1.1;CM-VER=3.1;

Thu Dec 05 02:12:09 2019

Warning (5)

Dynamic Range Window violation

Thu Dec 05 02:12:09 2019

Warning (5)

RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=[REDACTED];CMTS-MAC=[REDACTED_2];CM-QOS=1.1;CM-VER=3.1;

Wed Dec 04 23:02:45 2019

Warning (5)

Dynamic Range Window violation

Wed Dec 04 23:02:45 2019

Warning (5)

RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=[REDACTED];CMTS-MAC=[REDACTED_2];CM-QOS=1.1;CM-VER=3.1;

Wed Dec 04 22:17:49 2019

Warning (5)

Dynamic Range Window violation

Wed Dec 04 22:17:49 2019

Warning (5)

RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=[REDACTED];CMTS-MAC=[REDACTED_2];CM-QOS=1.1;CM-VER=3.1;

Wed Dec 04 09:53:14 2019

Warning (5)

Dynamic Range Window violation

Wed Dec 04 09:53:14 2019

Warning (5)

RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=[REDACTED];CMTS-MAC=[REDACTED_2];CM-QOS=1.1;CM-VER=3.1;

Wed Dec 04 06:57:29 2019

Warning (5)

Dynamic Range Window violation

Wed Dec 04 06:57:29 2019

Warning (5)

RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=[REDACTED];CMTS-MAC=[REDACTED_2];CM-QOS=1.1;CM-VER=3.1;

Tue Dec 03 22:05:25 2019

Critical (3)

SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=[REDACTED];CMTS-MAC=[REDACTED_2];CM-QOS=1.1;CM-VER=3.1;

Tue Dec 03 21:53:21 2019

Warning (5)

Dynamic Range Window violation

Tue Dec 03 21:53:21 2019

Warning (5)

RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=[REDACTED];CMTS-MAC=[REDACTED_2];CM-QOS=1.1;CM-VER=3.1;

Tue Dec 03 21:53:21 2019

Warning (5)

Dynamic Range Window violation

Tue Dec 03 21:53:21 2019

Warning (5)

RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=[REDACTED];CMTS-MAC=[REDACTED_2];CM-QOS=1.1;CM-VER=3.1;

Tue Dec 03 21:53:07 2019

Notice (6)

TLV-11 - unrecognized OID;CM-MAC=[REDACTED];CMTS-MAC=[REDACTED_2];CM-QOS=1.1;CM-VER=3.1;

Time Not Established

Notice (6)

Honoring MDD; IP provisioning mode = IPv6

Time Not Established

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[REDACTED];CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;

Tue Dec 03 19:30:11 2019

Notice (6)

CM-STATUS message sent. Event Type Code: 3; Chan ID: N/A; DSID: �; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=[REDACTED];CMTS-MAC=[REDACTED_2];CM-QOS=1.1;CM-VER=3.1;

Tue Dec 03 19:30:11 2019

Warning (5)

Unicast DSID PSN startup error

Tue Dec 03 19:29:28 2019

Notice (6)

TLV-11 - unrecognized OID;CM-MAC=[REDACTED];CMTS-MAC=[REDACTED_2];CM-QOS=1.1;CM-VER=3.1;

Time Not Established

Notice (6)

Honoring MDD; IP provisioning mode = IPv6

 

 

Gold Problem Solver

Re: Very slow upload speed

Yes, the signal level image is visible now. The downstream channel levels are weak, and the upstream levels are too high. And the "Dynamic Range Window violation", "Commanded Power Exceeds" and other errors in the log suggest an intermittent coax connection.

 

Signal problems are often due to loose, damaged, or corroded coax or coax connectors, usually in or near your home. If you can't find the problem or you'd rather have Comcast take care of it, call them at the phone number on your bill or 1-800-Comcast, or use one of the options on https://www.xfinity.com/support/contact-us/. If they can't fix the problem remotely (unlikely), insist they send a tech out to identify the cause and correct it.

If the tech finds bad coax, splitters, amplifiers, or connections in your home (even if Comcast originally supplied them) you'll probably have to pay for the visit unless you have their Service Protection Plan (https://www.xfinity.com/support/articles/service-protection-plan, closed to customers that don't already have it). If the trouble is due to a faulty Comcast rental device, or anything outside your home, you shouldn't be charged.

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Frequent Visitor

Re: Very slow upload speed

Thank you for your insight! I really appreciate it. I think I'll move the gateway to the first splitter in the basement, disconnect everything else, and check the singal levels there before calling Comcast - just to mitigate the risk of being charged for the visit.

 

Per the link you sent, I'm targeting these levels, correct?

Downstream Power Levels: -8dBmV to  +10dBmV (Currently too low at -11.4 to -9.0)

Downstream Signal to Noise Ratio (SNR):  >35dB  (Currently fine)

Upstream Power Level:  +25dBmV to +54dBmV (Currently too high at +55.5)

Upstream Signal to Noise Ratio (uSNR): >31dB   (Currently unknown?)

Upstream Receive Power: -2dBmV to +2dBmV (Currently unknown?)

Highlighted
Gold Problem Solver

Re: Very slow upload speed


@CnSWEST wrote: ... I think I'll move the gateway to the first splitter in the basement, disconnect everything else, and check the singal levels there before calling Comcast ...

I think that's a solid plan.

 


... Per the link you sent, I'm targeting these levels, correct? ...


Correct, except that I always like to see upstream power below +50 dBmV if possible. To me, +54 is borderline/too high, but that's how some modems run.

 

Note that Upstream Signal to Noise Ratio (uSNR) and Upstream Receive Power can only be measured by Comcast, not at the modem. Some reps know enough to find them for you, most do not.

 

Please let us know your results, thanks.

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Frequent Visitor

Re: Very slow upload speed

Here are the results of being attached directly to the incoming coax line for the house.

 

20191210 1600EST COMCAST connection at PoE.png

 

Per our discussions:

Downstream Power Levels: -8dBmV to  +10dBmV

Office: Currently too low at -11.4 to -9.0

PoE: On the high side. 7 to 10.1

Downstream Signal to Noise Ratio (SNR):  >35dB

Office: fine.

PoE: fine. 40.9 to 41.6 dB

Upstream Power Level:  +25dBmV to +50dBmV

Office: Too high, +55.5

PoE: fine. 40.5 dBmV.

 

Notably, I ran a speed test connected to the modem and had the same results as I have in the office. 360 down, ~10 up. Do you think this is sufficient for Comcast to investigate the matter without charging me?

 

Highlighted
Expert

Re: Very slow upload speed


@CnSWEST wrote:

Here are the results of being attached directly to the incoming coax line for the house.

 

20191210 1600EST COMCAST connection at PoE.png

 

Per our discussions:

Downstream Power Levels: -8dBmV to  +10dBmV

Office: Currently too low at -11.4 to -9.0

PoE: On the high side. 7 to 10.1

Downstream Signal to Noise Ratio (SNR):  >35dB

Office: fine.

PoE: fine. 40.9 to 41.6 dB

Upstream Power Level:  +25dBmV to +50dBmV

Office: Too high, +55.5

PoE: fine. 40.5 dBmV.

 

Notably, I ran a speed test connected to the modem and had the same results as I have in the office. 360 down, ~10 up. Do you think this is sufficient for Comcast to investigate the matter without charging me?

 


Can't see your picture just yet.

 

+7 to +10.1 is still on the high side but ok for being at PoE. Other than not knowing the uSNR nor the Upstream Receive Power currently, especially from the PoE, everything else seems fine from PoE indicating the problem could be inside as you are losing way too much from PoE to office. Are there any splitters that are not needed or are the connections tight?


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Expert

Re: Very slow upload speed

If the tech finds the problem to be on your side of the demarcation point, you will likely be charged.

 

Some stuff that you can try before you call;

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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Frequent Visitor

Re: Very slow upload speed

Here's the route trace from PoE to office:

  1. PoE
  2. MoCA Filter (Holland B00DC8IEE6)
  3. VoIP Amp and MoCA splitter, powered and grounded (Commscope CSMAPDU9VPI) - 6 alt paths connected, 1 used: media center MoCA adapter.
  4. RG6/U, ~30ft
  5. 2-way splitter (Holland GHS-2Pro-M) - 1 alt path connected, 0 unused
  6. RG6/U, ~40ft
  7. 3-way splitter (Ideal 85-333) - 2 alt paths connected, 0 used
  8. RG6/U, ~10ft
  9. RG6 keystone jack (VCE 4335095229)
  10. RG6/U, ~3ft
  11. 2-way splitter (GE 33526) - alt path used: MoCA adapter
  12. RG6/U, ~1ft
  13. Modem (Netgear CM1150V)

At the point of entry I am getting <50% of the advertised upload speed at best. That's the same result I'm getting when the modem is connected in my office. Do you not agree, then, that the root cause of the slow upload speed is independent of anything to do with my property? I'd rather divert my attention to the root cause of the immediate problem before improving my home network.

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Expert

Re: Very slow upload speed

After following EG’s steps, at that point since the slow uploads are happening at PoE, then it may be better to have a tech out to investigate. However the office will be one thing they will point out as well by saying there’s too much loss going there but since the issue happens at PoE, without knowing the uSNR or Upstream Receive Power, the issue may be beyond your premises

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New Poster

Re: Very slow upload speed

Probably because everyone in your neighborhood is Zooming at the same time.  I have Xfinity Extreme Plus witn 600/15 (dl/upload) and in the evening when everyone is done Zooming I get 14.8 mbs upload, but from 11 am to 5 pm I get only between 2.5-5.5 mbs. upload (sometimes less).  I asked Tech support at Xfinity and they confirmed that everyone in my neighbor uses the same bandwidth to upload, so if too many people uploaded at the same time it would lower my upload speed.  I even upgraded from 100/5 to 600/15, and it boosted my upload by about 50%, but that doens't help much when its mid day and i still can only get 2 mbs or less per second. Xfinity needs to upgrade its uploading capacities.  Your only other option is to swtich to a provider with higher upload speeds, or even better one like Sonic that has 1000 dl/ul - but that's fiber optic 1 gig service.

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New Poster

Re: Very slow upload speed

meant to say I get 14.7 upload after 5 pm, and about 2-5 mbs upload from 11 am - 5 pm.  The advertised speeds only apply when few people are using the internet.  That's why fiber optic is needed rather than shared cable internet.

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Expert

Re: Very slow upload speed

Dead thread from last year now being closed.



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