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Upload Speed 600x greater than download

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Frequent Visitor

Upload Speed 600x greater than download

All:

 

I'm at my wits end here.

 

We've always had 'some' amount of issue with our internet and XFinity/ComCast and have reached out multiple times, all to no avail.  Yet; I'm here trying once again because this is driving me absolutely crazy!

 

We recently added a new cable box to our XFinity account. After that, the internet worked well for a few days but quickly took a nosedive in relation to speed and connectivity for whatever reason.  Using both Google's speed test and XFinity's I've been seeing some very interesting results that are leaving me a little bit puzzled.  Our upload speed seems to range in the 550-600Mbps range (yes you read that correctly) and the download speed seems to be around 40/50Mbps.  Well outside of what we are paying for, but if I ever wanted to upload the Library of Congress to Google Drive it might perhaps shorten the time a few decades Smiley Wink.

 

I've taken all the items off of our home network.  Had ComCast/XFinity reset the line.  Rebooted the router and our WAP.  I work in Tech in San Francisco so I'm not too unknowledgable and I've done my homework.  This has got to be on Comcast/XFinity's side.

 

I've attached my signal/power levels and a screent shot of a recent Google Speed test result.

 

pl1.jpgCable Modem Signal/Power Level 1pl2.jpgCable Modem Signal/Power Level 2speed.jpgGoogle Speed Test Results

Expert

Re: Upload Speed 600x greater than download

What speeds do you get here ?;

 

http://speedtest.xfinity.com/

 

That kind of upload speed is not even physically possible with current DOCSIS cable systems.

 

 



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Frequent Visitor

Re: Upload Speed 600x greater than download

See below.   Less than 600 this time, but still quite a bit more than the 10/Mbps than I should be receiving.

 

pl3.jpg

Frequent Visitor

Re: Upload Speed 600x greater than download

That kind of upload speed is not even physically possible with current DOCSIS cable systems.

 

Understood and agreed.  However; I have tried both XFinity, Google's, and DSL Report's test applications from a laptop/desktop/tablet all running different OSs and with different browsers.  I've even swaped out my WAP/Router for another I had in storage, wiped NVRAM and reconfigured, and still have the same results.

 

*shrug*

Expert

Re: Upload Speed 600x greater than download

If this is regular coax cable from the pole / drop DOCSIS based service them I am stumped as to how you are getting that much upload speed !

 

FWIW, A current single 64 QAM modulated, 6.4MHz-wide, 5.120 MSym/sec upstream channel supports a raw data rate of approximately 30.72 Mbps and a real world throughput of approximately 27 Mbps. You have 4 bonded upstream channels. 27x4=108

 

BTW, your upstream power is too high and this should be addressed. But this by no means could have anything to do with higher upload speeds. If anything, it should be exactly the opposite. Lower than normal upload speed.



I am not a Comcast Employee.
I am a fellow customer, 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.

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Frequent Visitor

Re: Upload Speed 600x greater than download

I noticed that the power on the upstream bonded channels were above 50dBmV and that the thinking is that they should be ~<50dBmV.  I dunno.  I'm Software focused in my career and not DOCSIS 3.1 infrastructure/architecture so XFinity is going to have to figure this one.

 

All I know is that I'd prefer having my 250Mbps/15Mbps I signed up for versus what I am currently experiencing.

Expert

Re: Upload Speed 600x greater than download

@jb7891  Wow, you got magic upload speed! Smiley Wink

I've asked a Comcast employee to take a look. You should expect a reply in this thread. 

 

 

 


I am not an employee.
Expert

Re: Upload Speed 600x greater than download


@jb7891 wrote:

I noticed that the power on the upstream bonded channels were above 50dBmV and that the thinking is that they should be ~<50dBmV.  I dunno.  


40 to 45 dB is preferred. Here are some things that you can try;

 

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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I am a fellow customer, volunteering my time to help other customers here in the Forums.
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Frequent Visitor

Re: Upload Speed 600x greater than download

I've asked a Comcast employee to take a look. You should expect a reply in this thread

 

Awesome!  Thank you very much!  Yeah; if it was a real upload speed (or better yet a download speed) I'd be a very happy camper Smiley Wink

Frequent Visitor

Re: Upload Speed 600x greater than download

There is a three-way splitter on the line coming into the premesis which can unfortunately not be avoided.  It is however a brand new splitter (two ports for -7dBm for the cable boxes, and one -3dBm for the cable modem) and a high quality one.  All the coax running from the splitter is very-high quality and brand new -- supplied by Comcast/XFinity.  All the set-top boxes are brand-new and all coax into them are hand-tightened.

Frequent Visitor

Re: Upload Speed 600x greater than download

I'm sorry.  I went and double-checked and misspoke.  It is now a single-splitter coming in from the line which is two way.  I removed the three-way a few weeks ago.

Official Employee

Re: Upload Speed 600x greater than download

Hi jb7891m I can review signals on my side for you.   Please send me a private message with your account information (your name, address and account number).

 

Thank you

Frequent Visitor

Re: Upload Speed 600x greater than download

Good Morning ComcastPhil:

 

I have sent the information you have requested via private message.  Thank you for looking into this for me; I look forward to having my service back to a normal (and theoretically possible) speed.

Official Employee

Re: Upload Speed 600x greater than download

Thank you for your private message. I have responded.

 

Thank you

Frequent Visitor

Re: Upload Speed 600x greater than download

Hi Phill:

 

I sent you a response as well.  Thank you for taking a look at this for me.

Frequent Visitor

Re: Upload Speed 600x greater than download

Good Afternoon Phill:

 

I did notice the reset of the cable modem yesterday afternoon late PST.  As far as speed goes, last night I was able to get a period of 100-120Mbps for about three hours.  However; after I just checked it (the screenshot results are below), we're back down to slow download speeds albeit with considerably lower upload speeds (in the range I would expect).

 

Anything we can do to bump up my download speeds so that I'm at least somewhat close to what I am paying for at 250Mbps?

 

Thanks!

 

05102018_test.jpg

Official Employee

Re: Upload Speed 600x greater than download

Hi jb7891, I have responded to your private message.

 

Thank you 

Official Employee

Re: Upload Speed 600x greater than download

Hi jb7891, thank you for working with me in private message and glad we were able to get a technician out for you. Please reach out if you have any questions in the future.

 

Thank you