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Upstream channel power levels too low - what to do.

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Upstream channel power levels too low - what to do.

I'm paying for the most expensive plan available at my apartment complex (Gigabit). I'm getting ~600 Mbps download (which I'm okay with), and ~5 Mbps upload. The upload speed has become unbearable and, honestly, unacceptable for a top-tier modern internet plan.

 

For reference, 5 Mbps upload speeds means it takes 40 minutes to upload a 10-minute home video to social media. 5 Mbps means streaming gameplay on something like Twitch is guaranteed to be horrible quality. 5 Mbps means having choppy video calls with family back home. 5 Mbps means my personal file server is painfully slow outside of the local network.

 

When I called support this morning, after 40 minutes of running identical speed tests and four separate modem restarts, the support agent directed me to call my modem manufacturer Arris. Instead of doing that, I looked into my modem (SB6190) myself and found this:

 

Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 3 5120 kSym/s 23.70 MHz 43.25 dBmV
2 Locked ATDMA 2 5120 kSym/s 30.10 MHz 43.25 dBmV
3 Locked ATDMA 1 5120 kSym/s 36.50 MHz 43.25 dBmV

 

Arris' FAQ says that acceptable upstream signal levels should be no less than 45 dBmV:

 

https://arris.secure.force.com/consumers/articles/General_FAQs/SB6190-Cable-Signal-Levels/

 

My modem is reading a power level of 43.25. In this situation the FAQ directs me to ask my service provider to adjust the levels. So here I am, asking. Please, sir, may I have some more upstream bandwidth?

 

@ComcastMorgan this is extremely similar to another thread you answered: https://forums.xfinity.com/t5/Your-Home-Network/upstream-channel-power-levels-too-low-what-to-do/td-...

The solution there appears to have been a modem swap, but the symptoms were different (outages and packet loss vs. upstream bandwidth). Do you believe a modem swap would help me here as well?

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Re: Upstream channel power levels too low - what to do.

The upstream power is fine. The SB6190 is only a DOCSIS 3.0 capable modem. You will never get gig speeds with it. You need to use a DOCSIS 3.1 capable modem such as one of these;

 

https://www.amazon.com/Next-Generation-ARRIS-SURFboard-SB8200-DOCSIS/dp/B01N6SKK1G

 

https://www.amazon.com/Motorola-MB8600-Certified-Comcast-Communications/dp/B0723599RQ

 

https://www.amazon.com/NETGEAR-CM1000-DOCSIS-Ultra-High-download/dp/B01I5TJGSE



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Re: Upstream channel power levels too low - what to do.

DOCSIS 3.0 is capable of up to 200 Mbit/s. I'm getting five. Are you SURE a new modem is the solution?

 

DOCSIS version[14] Production date Maximum downstream capacity Maximum upstream capacity Features
1.0 1997 40 Mbit/s 10 Mbit/s Initial release
1.1 2001 40 Mbit/s 10 Mbit/s Added VOIP capabilities, standardized the DOCSIS 1.0 QoS mechanisms
2.0 2002 40 Mbit/s 30 Mbit/s Enhanced upstream data rates
3.0 2006 1.2 Gbit/s 200 Mbit/s Significantly increased downstream/upstream data rates, introduced support for IPv6, introduced channel bonding
3.1 2013 10 Gbit/s 1–2 Gbit/s Significantly increased downstream/upstream data rates, restructured channel specifications
4.0 2017 10 Gbit/s 10 Gbit/s Introduces support for fully symmetrical speeds
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Re: Upstream channel power levels too low - what to do.

They will not push a gigabit speed tier configuration file to a DOCSIS 3.0 modem. It will default to using a slower speed tier config.



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Re: Upstream channel power levels too low - what to do.

Okay, I'll get a new modem with 3.1 now.

 

I don't know if I believe you about the active speed tier degredation, though. There are no speed tiers between 300 Mbps and 1000 Mbps, and I've been getting ~600:

 

Download Speed Tier Measured Speed (Peak) Upload Speed Tier Measured Speed (Peak)
5 Mbps 5.95 Mbps(1) 1 Mbps 1.21 Mbps(1)
10 Mbps 11.8 Mbps(1) 1 Mbps 1.21 Mbps(1)
10 Mbps 11.8 Mbps(1) 2 Mbps 2.4 Mbps(1)
25 Mbps 29.41 Mbps 0.768 Mbps 0.89 Mbps(1)
50 Mbps 57.56 Mbps(1) 5 Mbps 5.92 Mbps
75 Mbps 83.11 Mbps 10 Mbps 11.89 Mbps
100 Mbps 111.07 Mbps 5 Mbps 5.92 Mbps
150 Mbps 151.65 Mbps(1) 20 Mbps 23.73 Mbps(1)
200 Mbps 221.07 Mbps(1) 10 Mbps 11.89 Mbps(1)
250 Mbps 265.1 Mbps(1) 25 Mbps 29.7 Mbps(1)
300 Mbps 318.2 Mbps(1) 25 Mbps 29.7 Mbps(1)
1 Gbps(2) 931.51 Mbps(1)(3) 35 Mbps(2) 38.25 Mbps(1)
2 Gbps 2,086 Mbps(1) 2 Gbps 2,060 Mbps(1)
(1)Based on independent measurements by Comcast (2)Available in most, but not all, markets
(3)Due to current technological limitations related to the capabilities of Ethernet ports in current hardware, download speeds through those ports for 1 Gbps service are limited as specified in the table above.

 

I suppose they could be putting me on an unlisted "tier". At the very least a new modem will improve my download speeds, I see that now. But my biggest concern remains the upload speed. I'm cautiously hopeful those will improve too.

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Re: Upstream channel power levels too low - what to do.


@shoffing1 wrote:

I don't know if I believe you about the active speed tier degredation, though.


Believe what you will.....



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Re: Upstream channel power levels too low - what to do.

You were right, my modem was the issue. I went to Microcenter and picked up a DOCSIS 3.1 modem (the motorola one you sent).

 

The support person should have seen this incompatability, and I resent the fact that I spent 40 minutes on the phone accomplishing nothing this morning, but I'm glad to have the problem resolved. I'll be sure to come to the forums first in the future.

 

I'm getting 40 Mbps up right now, which is better than what Comcast "advertises" in that table above.

 

Thank you for your help! I really appreciate it.

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Re: Upstream channel power levels too low - what to do.

How 'bout that ! Happy surfing !! 



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