U

Visitor

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5 Messages

Thu, Apr 29, 2021 4:43 PM

Upgrade from Arris TM822R to Arris SBV3202 – Good download improvement but still stuck with 6 Mpbs Upload speed

I have been using Arris TMR822R for years, got an upgrade to 1 Gbps more than a year ago and only decided recently to upgrade to Arris SBV3202 to improve my overall performance.

Performance on Arris TM822R was/is:

Max Download speed 300 Mbps, Upload Speed: 6 Mbps. Please note that I used to get 12 Mbps in upload and only in the last few months I observed that the upload speed had degraded to 6 Mpbs. The upstream parameters of TMR822R showed an upstream power below the acceptable signal level: +51 dBmV to 45 dBmV (see https://arris.secure.force.com/consumers/articles/General_FAQs/TM822G-CT-TM822R-Cable-Signal-Levels/?l=en_US&fs=RelatedArticle)

Upstream

UCID

Freq

Power

Channel Type

Symbol Rate

Modulation

Upstream 1

78

30.10 MHz

36.50 dBmV

DOCSIS2.0 (ATDMA)

5120 kSym/s

64QAM

Upstream 2

80

17.30 MHz

35.75 dBmV

DOCSIS2.0 (ATDMA)

5120 kSym/s

64QAM

Upstream 3

79

23.70 MHz

35.75 dBmV

DOCSIS2.0 (ATDMA)

5120 kSym/s

64QAM

Upstream 4

77

36.50 MHz

35.50 dBmV

DOCSIS2.0 (ATDMA)

5120 kSym/s

64QAM

 

Performance on Arris SBV3202:

Max Download speed 720 Mbps – good improvement but Upload Speed still at 6 Mbps. The upstream parameters of  SBV3202 showed an upstream power below the acceptable signal level of +51 dBmV to 45 dBmV as with TM822R (see https://arris.secure.force.com/consumers/articles/General_FAQs/SBV3202-Cable-Signal-Levels)

Upstream

UCID

Freq

Power

Channel Type

Symbol Rate

Modulation

Upstream 1

78

30.10 MHz

36.50 dBmV

DOCSIS2.0 (ATDMA)

5120 kSym/s

64QAM

Upstream 2

80

17.30 MHz

36.75 dBmV

DOCSIS2.0 (ATDMA)

5120 kSym/s

64QAM

Upstream 3

79

23.70 MHz

35.50 dBmV

DOCSIS2.0 (ATDMA)

5120 kSym/s

64QAM

Upstream 4

77

36.50 MHz

36.00 dBmV

DOCSIS2.0 (ATDMA)

5120 kSym/s

64QAM

 

 

I contacted Arris and they confirmed that the Upstream Power level was not within the expected range.

I did contact Comcast through the chat and asked to check the Upstream power level on their side. The representative was not able to confirm it. Instead I was only given what seems the standard answer: “the modem is unable to handle the speed, I'd suggest you to check with the Original Manufacturer”. Very helpful. There was no change in my house internal connections in the past 2 years so if my upstream signal level went down in the past months, it is more likely due to some work Comcast did in my neighborhood, like for example connecting my new neighbor few months back.

How do we reach technical support Tier 2 at Comcast so I can get real support on this issue?

Responses

EG

Expert

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87.1K Messages

2 m ago

You'll never get the full gig speed or the proper upload speed with that modem as it is only DOCSIS 3.0 compliant. You need a DOCSIS 3.1 capable device.

Visitor

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5 Messages

My problem is not download speed . 6 months ago, I was getting 12 Mbps upload with TM822R and now I need to change to a DOCIS 3.1 compliant modem to get back to 12+ Mbps. Sorry but this does not make sense.

EG

Expert

 • 

87.1K Messages

Suit yourself..... Good luck !

BruceW

Gold Problem Solver

 • 

22.4K Messages

2 m ago

... got an upgrade to 1 Gbps ... recently to upgrade to Arris SBV3202 ...

Using devices on speed tiers for which they are not approved tends to produce unexpected results. Please see https://www.xfinity.com/support/devices/.

Visitor

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5 Messages

1 m ago

So let me get this right. I have a modem which according to Comcast is matching the 800 Mbps download speed (as it is rated 940 Mbps by Comcast).

The 800 Mbps speed tier also provides up to 20 Mbps upload speed. 

There is nothing wrong with my connection as the Comcast technician that came to my house confirmed my connection was good for up to 42 Mbps upload.

So if I was on the 800n Mbps tier, I would likely get up to 20 Mbps upload. I need to note that I asked Comcast customer service to just downgrade me to the 800 Mbps and charge me the same price for my triple pay plan - I was told they could not do that without also changing my TV plan.

One interesting reddit thread – issue exactly like mine – shows a good example of the replies we get from the Comcast community.

https://www.reddit.com/r/Comcast/comments/mm4qtu/stuck_at_6_mbps_upload_on_gigabit_internet_with/

The most interesting reply however is the following:

“If a customer-owned modem doesn't support the speed, it gets provisioned with a default bootfile. The max speed is about 700/6 on the default bootfile. I ran into this issue with my 16x8 modem when I switched to Extreme Pro and hadn't received my XB7. The only solution is getting a DOCSIS 3.1 modem.” Strange as 700/6 is exactly what my modem provides me today.

 

I call this behavior “capping”.  I can understand that Comcast employees would follow the party line and refuse to agree this is capping. But  I do not understand why any non Comcast employee in the Xfinity Community  could be fine with this behavior and just repeat the Comcast line: "Get a better modem". This is just capping.

 

EG

Expert

 • 

87.1K Messages

"Capping". What a catchy term since the beginning of cable broadband time..... You still don't get it.... It's not a matter of a "better" modem. It's a matter of a device that their system will actually be able to accept the proper speed configuration file (it's not better, it's a standard)..... You REQUIRE a DOCSIS 3.1 capable device......

(edited)

Visitor

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5 Messages

So in order to buy the Comcast policy, you appear to claim that a DOCIS3.0 modem can ONLY provide an upload speed of 6 Mbps...when you know that is not true. In case you do not: My old DOCSIS3.0 modem works at 12 Mbps for more than a year until Comcast decided to cap it at 6 Mbps.  Who does not get it?

EG

Expert

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87.1K Messages

You. Only a slower speed config file will be pushed to a non-compliant device. That includes a lower tier upload speed.

(edited)

Visitor

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5 Messages

"Only a slower speed config file will be pushed to a non-compliant device. That includes a lower tier upload speed."

Thank you for clearly pointing out the Comcast policy. I clearly understand it.

The issue I have with it is that it does force the modem to a lower upload speed than it is able to provide.

As an example, Comcast customers using a DOCSIS3.0 modem like mine - a modem  compliant to the 800 Mbps tier and paying for a 800 Mbps - will be able to enjoy the upload speed of that tier - i.e.; 15-20 Mbps . In the case of the use of a modem like mine on 1 Gbps plan, modem that Comcast considers only compliant to 800 Mbps, Comcast has clearly the choice to program them like a 800 Mbps modem under a 800 Mbps plan (this choice would be consider fair and acceptable). However that is not the choice Comcast made. Comcast decided to penalize those customers paying the higher price with the lower upload speed they could decently program them with: 6 Mbps. In doing so, Comcast is clearly capping those customers not based on the capability of their modem but on an arbitrary and discriminatory setting. It is unacceptable and I truly fail to understand why anyone would consider this policy acceptable. 

I will escalate this issue to Comcast executive management, my state board of utilities and the FCC if necessarily.

Visitor

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3 Messages

1 m ago

From your tables in the first post, it looks to me like your SBV3202 is tuning only 4 upstream channels.  The TM822 is an 8x4 telephony modem, the SBV3202 is a 32x8 telephony modem.  So you should have doubled the number of upstream channels being tuned, from 4 to 8.  Either the modem is bad and is not tuning more than the original 4 upstream channels, or Comcast has not mapped additional upstream channels to handle the network traffic on the return path towards the local node.

(edited)

BruceW

Gold Problem Solver

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22.4K Messages

1 m ago

... you should have doubled the number of upstream channels being tuned, from 4 to 8 ...

That's not correct. 4 channels is more than enough to deliver the 35 Mbps upstream Gigabit service provides. The problem, as stated above, is that the device is not approved by Comcast for Gigabit service.

(edited)

Visitor

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3 Messages

And I don't agree with you either.  The OP's upstream power levels suggest to me that he is probably close to the node.  If his modem is only tuning 4 upstream channels, or if Comcast channel mapping is only providing 4 channels in the return path, then the amount of traffic already in the pipe gives his modem few chances to communicate with the CMTS.

I'm just a former Comcast Comm Tech using the same SBV3202 modem that the OP has in questioning his upstream speeds.  I'm not on a Gigabit plan, but I have maintained the same 25Mbps upstream speed that I had with my previous telephony modem.

EG

Expert

 • 

87.1K Messages

1 m ago

Comcast currently offers a max of 4 to 5 upstream channels.

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