How does Xfinity determines the "wired download speed"?

I am currently on the 1.2gbps plan and my modem is Motorola MB8600. The device info pages says the "wired download speed" is 890mbps, and I couldn't find such number in Motorola's datasheet, which mentions 3.8gbps as the maximum downstream speed. I have two questions:

1) how does Xfinity determines the "wired download speed"? Is it obtained through some lab tests? Or it there a formula to calculate the speed given a device's specs?

2) would this number change if Xfinity changes their services or protocols? Maybe my memory is falling apart as I vaguely remember about a year ago my plan speed was 1gbps and I bought this modem because Xfinity says it has a "wired download speed" greater than 1gbps.

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user_bb801b

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167 Messages

3 years ago

By "wired" assuming you mean ethernet cable connected speed vs WIFI signal?

I also have 1Gbp service and have experienced issues getting the 1Gbps that Im paying for, but to answer your question, the "speed" is measured either by Comcast tech using a meter connected directly to the XB7, someone with access to network using other technical means to measure speed, or lastly - most commonly, by endpoint user running "speed test" over the internet.

Rather than a formula, I suppose there is data in the device specs that shows throughput capacity of the device. However, most device that fall into the "Gigabit ethernet" category are 1Gbps compatible and suitable for most end user purposes, i.e. streaming, browsing etc., if that's what you're getting at.

Also Ive noticed that Comcast compels users to the Arris XB7 rather than store bought modems and as reluctant as I was at renting the XB7 has performed flawlessly as opposed to the Motorola Surfboard that I purchased and suddenly became incompatible due to network upgrades.. Just my opinion..

Thanks and good luck.

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user_137759

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2 Messages

@user_bb801b Thanks for the reply. I am not sure about "wired" either; I just simply copied the whole term "wired download speed" from Xfinity webpage.

3 years ago

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EG

Expert

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106K Messages

@user_137759

FWIW, you won't get the full 1200 Mbps speed with that modem as it only has a 10/100/1000 (gigabit ethernet port) unless you use the LAG / LACP (Link Aggregation) feature.

The max is around 940 due to the ever-present ethernet overhead.

You need one of the newer modems that has a 2.5 gigabit ethernet port such as these;

https://www.amazon.com/ARRIS-Surfboard-S33-Multi-Gigabit-Ethernet/dp/B08FMSC5WZ

https://www.amazon.com/NETGEAR-Nighthawk-Multi-Gig-Cable-CM2000/dp/B08GWNZ9VF/ref=sr_1_1?crid=1IIPL6TD9RBAH&dchild=1&keywords=netgear+cm2000&qid=1616429857&s=electronics&sprefix=netgear%2Celectronics%2C181&sr=1-1

https://www.amazon.com/MOTOROLA-MB8611-Ethernet-Approved-Comcast/dp/B08DDFKXKC

https://www.amazon.com/NETGEAR-Nighthawk-Multi-Gig-Cable-CM2050V/dp/B01N7LXR0W

(edited)

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3 years ago

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user_bb801b

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167 Messages

3 years ago

Thanks EG,

Hopefully this is not too far off topic but...

Im all about owning the modem vs renting but from what I gather Comcast adds secret sauce (proprietary config) to rental modems, at least in my experience, and fully supports the rental modem by providing the tech support/service, returns for faulty equipment, guarantees speed, compatibility, most current updates etc.

Are you suggesting that purchasing the 2.5Gbps device will provide end user with greater download speed than ~ 1Gbps and or up to 2.5Gbps?

Its my experience that Comcast is not pushing more than 1Gbps download speed through the pipe and buying a more expensive modem does not guarantee or result in greater bandwidth. Perhaps for business class service that's a possibility?

Also in my experience, if the home user encounters issues, tech support often points to the DOCIS 3.0 modem not configured properly or not meeting the high standards that the proprietary ARRIS XB7 provides.

Please correct me if Im wrong, or off base because Im happy to upgrade to 2.5Gbps if the end result is improved QOS and curious does the benefit outweigh the cost. Quick web search suggest streaming 4k consumes 25Mbps .

Thanks and good luck.

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EG

Expert

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106K Messages

@user_bb801b

Thanks EG,

Hopefully this is not too far off topic but...

Im all about owning the modem vs renting but from what I gather Comcast adds secret sauce (proprietary config) to rental modems, at least in my experience,

Yes. The firmware is somewhat customized by them but more so with the combo modem / router gateway devices rather than straight / plain vanilla cable modems. With gateway devices they are providing the firmware loads for both the cable modem component and the router component.

and fully supports the rental modem by providing the tech support/service, returns for faulty equipment, guarantees speed, compatibility, most current updates etc.

Yes.

Are you suggesting that purchasing the 2.5Gbps device will provide end user with greater download speed than ~ 1Gbps and or up to 2.5Gbps?

You should get around 1400 Mbps due to their gig speed tier now being 1200 down instead of 1000. And due to the fact that there is a 20% speed overprovisioning.

Its my experience that Comcast is not pushing more than 1Gbps download speed through the pipe and buying a more expensive modem does not guarantee or result in greater bandwidth. Perhaps for business class service that's a possibility?

They are pushing ~1400 as stated above.

Also in my experience, if the home user encounters issues, tech support often points to the DOCIS 3.0 modem not configured properly or not meeting the high standards that the proprietary ARRIS XB7 provides.

FWIW, it's DOCSIS 3.1. And all devices have to conform to the DOCSIS standards whether rented from them or retail purchased / customer owned. Of course, they are going to push their rented devices. What company wouldn't.

Please correct me if Im wrong, or off base because Im happy to upgrade to 2.5Gbps if the end result is improved QOS and curious does the benefit outweigh the cost. Quick web search suggest streaming 4k consumes 25Mbps .

There really isn't any improved QoS except for the increased bandwidth that the gig speed tier provides.

As far as the benefit to cost ratio goes, you get to decide that 😉 😊

(edited)

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3 years ago

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How does Xfinity determines the "wired download speed"?

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