S

Contributor

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46 Messages

Thursday, March 3rd, 2022 12:16 PM

Closed

upload drops 0-2000 Kbps unstable

Tested with xfinity rental modems xb3, xb6, xb7
Tested with xfinity approved modems c7000v2 Docis 3.0, SB8200 Docis 3.1, G36 Docis 3.1
Tested with bridgemode and non-bridgemode

Unstable download speeds and unstable upload speeds despite paying for Gigabit speeds.
I am monitoring all internet traffic in and outside of our home via Bandwidth Traffic Monitoring software.
So I know exactly which devices are uploading and which devices aren't.

After 5pm CST anyone on our network downloading through Xfinity Internet Service
causes downstream and upstream to become unstable to the point of being unusable.
This behavior steadily worsens after 5PM lasting all the way to 1am when it magically stops.

At the time of the outages the devices in our home are collectively pulling
no more than 30Mbps download with max 2Mbps upload.

Previously we were extreme customers and for over 15months
we got 600-900Mbps downstream with less than 5Mbps upstream.
We expect at least 600Mbps of our promised and paid for 1200Mbps.
However on Gigabit when we are home and the when the internet works
most of the time we don't get more than 400Mbps with 17Mbps upload and when
we try to use the service speeds randomly drop down to zero every 1-5 minutes.

On February 7th
to increase our upload stability we upgraded our extreme package to a gigabit plan.

By February 8th
we had 900Mbps down with 38Mbps up.

February 11th
Xfinity comes out at 5pm cst and destroys our outside panel to fix a signal leak.
https://youtu.be/thjvvthks9c

March 1st
Xfinity came out to replace 20 year old splitters and to consolidate
our coax to one jack in the home.

While the technician was here the internet was performing fine however
the very next day our issues returned.

When I try to upload a live video stream of 6000Kbps I can't.
I see peaks of 2000Kbps and then the speed rapidly drops to 0.

I have tried to consolidate the network to one
PC in bridge mode and I still have these issues.

When I connect a new MAC address to the Modem I am able to obtain a new
external IP address and for about 3 days I am able to stream and download without issue.
This means every time I want to guarantee service I have to create a fake MAC address to
ensure adequate speeds are available for my desired streaming tasks.

I should not have to request a new IP from Xfinity DHCP every time I want to use my service.
I pay for unlimited data [Edited: "Inflammatory"]


so I'm here hoping someone who is more tech savvy will kindly explain
why I am having so many issues trying to upload a live stream of 6000Kbps when PC's on our network pull less than 30Mbps down.

With an expected 17Mbps upload and 600Mbps download you'd think a customer trying to use 6Mbps of the 35Mbps upload
and 30Mbps of the 600Mbps download should be no problem.
That is if the numbers being advertised aren't being exaggerated by Xfinity service.

The only setup I haven't tried is Dual WAN because it's extremely advanced and I'm still learning.

My next step is to explain to the public how I got 1200Mbps with 50Mbp upload on extreme services
for a week after Xfinity Support made a critical address error which resulted in
Xfinity Security[Edited: "Inflammatory"] getting involved with my account which to compensate
they boosted my signal to 1200Mbps with 50Mbps upload for a week.

I would really like to know where that speed has gone. Because I wasn't paying for it
then but I am now. and I am not getting the speed that I know for a fact is possible with
my existing equipment/lines.

Seems like this is becoming a problem everywhere in the mid-south area.

My advice to any other customers seeking real support:
[Edited: "Solicitation"]
These are your best options.
Doing anything else will result in Xfinity trying to
upsale you on new plans/equipment.
March 1st was the first actual Xfinity techician that was sent out to my home
all previous techs were contracted technicians.



------------------------------------------------------------------------------
I'm not official Xfinity support [Edited: "Inflammatory"]
I'm offering support to all other cases hoping someone looks at mine.
https://forums.xfinity.com/conversations/your-home-network/upload-drops-02000-kbps-unstable/6220b1aaaef5c36d133d6334

Contributor

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46 Messages

3 years ago

my posts here keep getting marked Private without any sort of notification how am I to understand why?

Downstream QAM

Index Frequency (MHz) Power Level (dBmV) SNR (dB) Modulation Lock Status
1 405 7.599998 40.366287 QAM256 Locked
2 411 7.400002 40.366287 QAM256 Locked
3 417 7.400002 38.983261 QAM256 Locked
4 423 7.099998 38.983261 QAM256 Locked
5 429 6.500000 38.983261 QAM256 Locked
6 435 5.699997 38.983261 QAM256 Locked
7 447 5.000000 38.983261 QAM256 Locked
8 453 5.099998 38.605377 QAM256 Locked
9 459 6.699997 38.983261 QAM256 Locked
10 465 7.599998 40.366287 QAM256 Locked
  • <<
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  • >
  • >>

Downstream OFDM

Index FFT Type Channel Width (dB) # of Active Subcarriers First Active Subcarrier (MHz) Last Active Subcarrier (MHz) Avg RxMER Pilot (dB) Avg RxMER PLC (dB) Avg RxMER Data (dB) Power Level (dBmV) Modulation Lock Status
159 4K 96 1844 673 766 47 42 41 12.1 QAM1024 Locked

Upstream QAM

Index Frequency (MHz) Power Level (dBmV) Channel Type Symbol Rate (KSym/sec) Modulation Lock Status
4 16.4 36.520599 US_TYPE_ATDMA 5120 KSym/sec 64QAM Locked
5 39.6 35.500000 US_TYPE_ATDMA 1280 KSym/sec 64QAM Locked
3 22.8 36.020599 US_TYPE_ATDMA 5120 KSym/sec 64QAM Locked
2 29.2 36.520599 US_TYPE_ATDMA 5120 KSym/sec 64QAM Locked
1 35.6 35.520599 US_TYPE_ATDMA 5120 KSym/sec 64QAM Locked



------------------------------------------------------------------------------
I'm not official Xfinity support [Edited: "Inflammatory"]
I'm offering support to all other cases hoping someone looks at mine.
https://forums.xfinity.com/conversations/your-home-network/upload-drops-02000-kbps-unstable/6220b1aaaef5c36d133d6334

(edited)

(edited)

Contributor

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46 Messages

3 years ago

[Edited: "Inflammatory"]. Do I really need to wait until Google fiber is available in my area
just to run 6000Kbps live upstream ?? really? if that happens. I will make it my life mission to station
myself in front of Xfinity Stores offering their customers my support for free.
Shoot I might even live stream the whole event via 4G LTE.

Because this is ridiculous.

------------------------------------------------------------------------------
I'm not official Xfinity support [Edited: "Inflammatory"]
I'm offering support to all other cases hoping someone looks at mine.
https://forums.xfinity.com/conversations/your-home-network/upload-drops-02000-kbps-unstable/6220b1aaaef5c36d133d6334

(edited)

Contributor

 • 

18 Messages

3 years ago

Hello,

we crossed paths in another thread.

The power levels on your OFDM channel look high.  Not out of spec (-15 to +15) but they are approaching the upper level.. Meanwhile your transmit power looks to be on the low side of things. What do you see in the modem error logs?

Downstream (Rx) Receive Power Level:
This is the amount of signal received by the modem from the transmitter in the cable company head-end.

For all modems DOCSIS 3.0 / 3.1:

-7 dBmV to +7 dBmV "Recommended"
-8 dBmV to -10 dBmV / +8 dBmV to +10 dBmV - "Acceptable"
-11 dBmV to -15 dBmV / +11 dBmV to +15 dBmV - "Maximum"
Lower than -15 dBmV & Higher than +15 dBmV - "Out Of Spec."

SNR (signal to noise ratio) levels:
This is how clear the signal is at either the modem receiver (downstream SNR) or the receiver in the cable company head-end (upstream SNR).

DOCSIS specifications list minimum CNR (carrier to noise ratio) levels not SNR levels. The SNR levels listed here are based on commonly recommended MER levels for digital cable signals. Not all QAM demodulator chipsets accurately calculate SNR levels that approximate actual MER levels, so these levels may vary depending on which chipset and/or firmware is used in the equipment.

*There is no upper SNR limit.

For all modems DOCSIS 3.0 / 3.1:

256 QAM: 30 dB minimum. 33 dB or higher recommended.
64 QAM: 24 dB minimum. 27 dB or higher recommended.
16 QAM: 18 dB minimum. 21 dB or higher recommended.
QPSK: 12 dB minimum. 15 dB or higher recommended.

Downstream SNR levels are read at the modem on the downstream data channel and can be viewed using the modem diagnostic screens.

Upstream SNR levels are read at the CMTS on the upstream data channel, not the modem or the modem diagnostic screens. The end-user cannot get the upstream SNR directly. Only the provider can read the upstream SNR level, directly from the CMTS. Also, the upstream SNR level provided by most CMTSs is not specific to any single modem, but is an averaged, aggregate level from all modems on that upstream channel on the upstream port.

Upstream (Tx) Transmit Power (a.k.a. Return Signal) level:
This is the amount of signal transmitted by the modem to reach the receiver in the cable company head-end.

*Recommended Upstream signal levels are +35 dBmV to +47 dBmV (DOCSIS 3.1)
*Recommended Upstream signal levels are +35 dBmV to +49 dBmV (DOCSIS 3.0)

50 dBmV maximum for OFDMA (DOCSIS 3.1)
52 dBmV maximum for A-TDMA, TDMA & SC-QAM (DOCSIS 3.0)
53 dBmV maximum for S-CDMA DOCSIS 2.0 (All Modulations)
54 dBmV maximum for 32 QAM and 64 QAM. (A-TDMA DOCSIS 2.0)
55 dBmV maximum for 8 QAM and 16 QAM. (DOCSIS 1.0, 1.1)
58 dBmV maximum for QPSK. (DOCSIS 1.0, 1.1)

Contributor

 • 

46 Messages

@user_24f3a2​ 

I'm not seeing anything but admin sys messages in my bridgemode modem. :(
you'd think being pretty nice cable modem it would have at least the last 7 days worth of logs.
It had 2 lines.

these are the specs.

Model: G36
Vendor: ARRIS Group, Inc.
Hardware Revision: 1
Processor Speed: 2559.69 MHz
DRAM Total Memory: 678 MB
DRAM Used Memory: 392 MB
DRAM Available Memory: 286 MB
Flash Total Memory: 462 MB
Flash Used Memory: 425 MB
Flash Available Memory: 37 MB

I am running a cat 6 cable out of the 2.5gb port to a RT-AX58U router.

but to test I've tried broadcasting 6000Kbps in bridge mode with one PC on cat6
and I still experience issues.

(edited)

Contributor

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18 Messages

Hi, it seems like a signal issue to me, your upstream seems very close to the low threshold which can cause dropped packets, re-transmits etc. Signal levels require a truck roll to fix.

I highly recommend checking out dslreports dot com  Lots of good information there as well as a comcast direct forum, they have been helpful to me in the past.

For signal levels you really want to be in the middle of the spectrum b/c temperatures will cause the levels to fluctuate. 40 is a good target for upstream. They always end up +/- 3 due to temps. They rise when it's hot, fall when it's cold.

(edited)

Expert

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107.1K Messages

3 years ago

FWIW. These are the current Comcast engineering / plant specs from the pinned "Troubleshooting Tips" topic at the top of the board;

Check your signal levels

To view your modem’s status page go to http://192.168.100.1 or http://10.0.0.1

 

Specification      Min             Max
Downstream Power Level    
Cable Modems -10dBmV +10dBmV
Gateways and EMTAs -7dBmV +7dBmV
Downstream Signal to Noise Ratio 35dB -
Upstream Power Level +35dBmV +50dBmV
Upstream Signal to Noise Ratio 31dB -
Upstream Receive Power -2dBmV +2dBmV

 

Note: Not all modems will allow you to view the status page and some will have different URLs to access this info. If you are unable to access your modem’s status page, you can contact Comcast Customer Support and ask the support representative for these values.

https://forums.xfinity.com/conversations/your-home-network/internet-troubleshooting-tips/602dae4ac5375f08cde52ea0 

Contributor

 • 

46 Messages

3 years ago

So I have been steadily working on this every day.
Still not getting great speeds. but I did find out.
After walking through my apartments and checking
over 30 cable panel boxes. All unlocked. All 6ft off the ground. 20 year old splitters.
All full of dirt grass old cables bugs. Nothing grounded. Nothing maintained.
Some of the panels were busted in and lying on the ground full of water and moss
even though it hadn't rained in days.

Xfinity tells me they will take my video testimonials to
corporate headquarters to make sure repairs are completed to my satisfaction.

I lately have been reporting speeds of 50Mbps down with 30Mbps up.

Xfinity has sent out RMT requests multiple times.
After failing 3 technician visits within 30 days Xfinity
approved RMT request. RMT Repair Service was carried out
March 15 2022 ~March 18 2022.
Service still constantly goes in and out when I'm home.
Mon-Fri 5PM~12AM
Sat-Sun 10AM-10PM

I have received so far a $20 credit. I have recorded outages from 2018 to present.
I have tried all rental equipment all internet plans and all commercially purchasable
cable modem equipment offered by major retail store BestBuy.

Nothing works. Xfinity's support offers to send more telecommunication technicians.
We've had over 14 technicians 2 which were super visors in the last 11 months.
We are still paying Gigabit customers getting partial delivery because live services are not usable.
I've made videos demoing my issues to share with technicians before they arrive.
I've recorded technicians visits and discussed all testing methods.
Xfinity support confirms daily that we have internet service issues
and that it's Xfinity policy to issue credits after service is repaired/restored.
Until my service is repaired I'm not eligible for credit.

Cable modems do not record loss of live service only power outages.
Onsite telecommunication technicians only test for signal ping to Comcast Xfinity Ooklah test servers.
File exchange has to happen to test bandwidth stability which is required for live services such as
OpenVPN, VOIP, Skype Business Video Conference, Teams Meeting Video Conference,
Twitch TV, YouTube Live, Discord Live, CNN Live News, ESPN Live Sports,
that's just from what I was able to test but Xfinity technicians have no approved tools
that test via consecutively growing file exchange.

Full HD 1080p Live video + 320Kbps Audio requires 6~10Mbps stable bandwidth downstream or upstream.
Achieving these speeds is extremely intermittent to the point internet is not usable.

(edited)

Official Employee

 • 

798 Messages

Hey there! I would love to help with these ongoing service level issues as well as with the repairs needed to the cable boxes outdoors.

 

Please send me a private message with your name and address to get started. 

 

To send a Private Message, please click on the chat icon in the top-right corner of the screen, next to the bell icon, and then type or select "Xfinity Support" to initiate a live chat.

I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer.tick
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