U

Visitor

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8 Messages

Tue, Oct 5, 2021 9:46 PM

Xfinity says I have a modem problem; Modem manufacturer says I have a cable problem

I've been experiencing significantly lower internet speeds (2-300mbps) than I'm paying for (1 gig).

A service technician came out to the house to test the line but was unable to -- he seemed to be an inexperienced contract worker who had to call his boss to figure out how to even do so.  In the end, both he and the phone representative say it must be a problem with my modem.

I have an Arris T25, which is relatively new and has not had problems until recently.  It's a high quality modem on Xfinity's approved list.

The modem manufacturer ran diagnostics and their end and said I am receiving low upload power from the cable company. 

Can comcast increase my upload power? Seems silly that I'd have to go spend hundreds of more dollars for a different modem. 

New Poster

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11 Messages

2 m ago

Does the modem match the tier speed of your internet? If not I think they automatically put you into IVP6 provisioning which prevents you from using DOCSIS 3.1, please post if you discover the problem. I can't get rid of the provisioning and it's screwing up my entire network, thanks Comcast 

Visitor

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8 Messages

@RedWings13,

Yes modem matches tier speed -- both up to 1 gigabit. 

At least according to my router settings, I'm on IPV6.  As for docsis 3.1, I'm unsure how to check.

BruceW

Gold Problem Solver

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23.1K Messages

2 m ago

@RedWings13 wrote: "... they automatically put you into IVP6 provisioning which prevents you from using DOCSIS 3.1 ..."

This is not correct. IPv6 provisioning ("IP provisioning mode = IPv6") just means Comcast is using IPv6 to manage the modem. That has nothing to do with the modem's ability to use DOCSIS 3.1 features to operate at Gigabit speeds.

New Poster

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11 Messages

@BruceW

On my router it says "Procedure: IP Provisioning Mode/  Status: Honor MDD/ Comment: IvP6 Only" 

shouldn't it say "DOCSIS 3.1 Allowed"? 

BruceW

Gold Problem Solver

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23.1K Messages

2 m ago

@RedWings13 wrote: "... shouldn't it say "DOCSIS 3.1 Allowed"?"

Why should it? The choice of IP version for device management has nothing to do with whether DOCSIS 3.1 is enabled or not. If you are having problems you won't solve them by focusing on the management protocol. It simply doesn't matter whether it's IPv4 or IPv6.

EG

Expert

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90.5K Messages

2 m ago

@RedWings13 FWIW. @BruceW is correct. If there are multiple bonded downstream and upstream channnel present, then DOCSIS  3.1 is present. The Internet Protocol that is being used does not matter. They are two different layers of the OSI model (Open Systems Interconnection). DOCSIS version has nothing to do with the modem provisioning. 3.1 is automatically and always present as long as you see bonded channels as was stated. As is the backward compatible 3.0 version always present.

(edited)

BruceW

Gold Problem Solver

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23.1K Messages

2 m ago

@user_804e2f wrote: "... lower internet speeds (2-300mbps) than I'm paying for (1 gig) ... I have an Arris T25 ..."

The problem may simply be that the T25 is not approved by Comcast for use with Gigabit service. See https://www.xfinity.com/support/devices ("Wired Download Speed: Up to 949 Mbps").

Visitor

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8 Messages

@BruceW 

Sure, but I'd happily take 949...Surely T25 couldn't be responsible for a drop down to the 2-300 range.

BruceW

Gold Problem Solver

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23.1K Messages

2 m ago

@user_804e2f wrote: "... Surely T25 couldn't be responsible for a drop down to the 2-300 range."

AFAIK Comcast has never said what happens when a customer uses a device that is not approved for their Internet speed tier, but the Forums are full of examples where the result is operation at speeds way below the manufacturer's speed rating.

Do yourself a favor and get an approved device. If I was in your shoes I'd try renting on of their gateway devices for a week or so to see what sort of speed that device offers. The cost would only be a few bucks and it would answer the question: "Is my modem the problem?".

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