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12 Messages

Thu, Sep 10, 2020 2:00 PM

Slow uploads during the daytime

I'm on the 300/10 Mbps plan (300 down, 10 up)

I get, pretty consistently, 300+ Mbps down, so no issue there.

But the upload speed I get varies massively during the day, often dipping to 1 Mbps, as demonstrated by ookla command-line speedtest. I check 3 nearby locations (comcast, FastMetrics & Unwired) every 30min, and I see the same behavior every work-day (also, school day):

  • 12 Mpbs upload for all non-work, non-school times
  • Dip to 1-2 Mbps during work/school hours
  • Typically a partial recovery at lunch time

I don't imagine any of my devices (e.g. modem, wifi-router) are causing the slowdown. The speed is measured from a wired device. I get very similar behavior from all 3 upload locations. The house often has 1 to 3 devices doing zoom, but this typically consumes only about 0.5 Mbps upload. The upload speed tests don't change depending on how many zoom calls we're doing.

 

In the picture you can see the upload speed drop every day this Tue - Thu, starting ~8am, with a noon recovery, and a messy afternoon recovery. The upload speed stays flat evenings, and all weekend.

 

Xfinity, can you make some adjustments?

 

comcastUpload.png

Third-party hosted image 

 

 

 

Responses

EG

Expert

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86.5K Messages

8 m ago

Can't see your pic. Since you are a new poster, it needs to be approved by a Forum Admin. That could take some time. In the interim, you could try hosting it at one of those free third-party pic hosting sites like Imgur or Photobucket and post the link to it here.

Or copy all of the text of the status page and paste it into the body of your next post here.

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Regular Visitor

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12 Messages

8 m ago

Thanks - added a link.

EG

Expert

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86.5K Messages

8 m ago

What do the modem's signal stats look like ? Try getting them here http://192.168.100.1 or here http://10.0.0.1

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

What is the exact make and model number of the modem ?


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bskitz

Frequent Visitor

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13 Messages

8 m ago

Could it simply be the network is heavily congested @ the times you are citing it being slow? Or does that not matter as much? I know some but I’m not heavily versed in networking so I’m just curious.
EG

Expert

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86.5K Messages

8 m ago

The upstream power is on the high side 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.

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Regular Visitor

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12 Messages

8 m ago

@EG I've linked the modem stats, but since my speeds are great in non-work hours, the modem (and router) should be fine.

@bskitz Yes I believe xfinity upload is generally congested in my area due to work-from-home & remote school, and I'm asking them to fix it. Xfinity continues to sell 300/10, knowing that they're only delivering 300/1 during the day, at least in this area.

 

The modem is Motorola MB7621 with these stats:

(external link) 

Screen Shot 2020-09-11 at 9.34.50 AM.png

 and (external link) 

Screen Shot 2020-09-11 at 9.35.00 AM.png

 

EG

Expert

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86.5K Messages

8 m ago

The issue could also be a capacity / traffic congestion problem but that won't cause a rise in the upstream power level. The stats don't lie. It is elevated and it may be intermittently fluctuating even farther out of spec, and this should be addressed regardless of anything else. Did any of the troubleshooting suggestions apply ?

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

Regular Visitor

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12 Messages

8 m ago

@EG OK upstream power may be on high side; I've no expertise here. But I don't think the upstream power gremlins know to behave at lunch time on work days. And to take Labor Day off. I.e. seems more likely Xfinity congestion in my area.

Frequent Visitor

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5 Messages

7 m ago

I'm seeing a similar behavior for the past 3 weeks or so. My neighbors ran into the same problem. We had Comcast technicians take a look inside the home and at the boxes on the street. Everything is in order and their conclusion was that this slowdown is coming from backend servers.

 

Comcast is throttling the upload speeds due to increased traffic of work from home and schooling. They need to increase capacity or they will lose more customers soon.

bskitz

Frequent Visitor

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13 Messages

7 m ago

RE: Throttling during the day...

Is this just through your most recent 3 week experience of slow upload speeds during day? Or do you have any hard evidence of throttling.

Note: I believe this 100%... I was jw.
bskitz

Frequent Visitor

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13 Messages

7 m ago

That spreadsheet definitely looks like throttling...

But I will say, that I’ve seen this before & it turned out in previous instances, it wasn’t Xfinity doing any throttling @ specific times...rather a hardware issue.

But hey, I could be very wrong. I do think you got a solid case tho! It’s all right there in your spreadsheet! And it’s consistent!

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