Add to your order
- Coverage for accidental damage including drops, spills, and broken parts, as well as breakdowns (plans vary)
- 24/7 support when you need it.
- Quick, easy, and frustration-free claims.
- No Additional Cost: You pay nothing for repairs – parts, labor, and shipping included.
- Coverage: Plan starts on the date of purchase. Malfunctions covered after the manufacturer's warranty. Power surges covered from day one. Real experts are available 24/7 to help with set-up, connectivity issues, troubleshooting and much more.
- Easy Claims Process: File a claim anytime online or by phone. Most claims approved within minutes. We will send you an e-gift card for the purchase price of your covered product. In some instances, we will replace or repair it.
- Product Eligibility: Plan must be purchased with a product or within 30 days of the product purchase. Pre-existing conditions are not covered.
- Terms & Details: More information about this protection plan is available within the “Product guides and documents” section. Simply click “User Guide” for more info. Terms & Conditions will be available in Your Orders on Amazon. Asurion will also email your plan confirmation with Terms & Conditions to the address associated with your Amazon account within 24 hours of purchase.
- No Additional Cost: You pay nothing for repairs – parts, labor, and shipping included.
- Coverage: Plan starts on the date of purchase. Malfunctions covered after the manufacturer's warranty. Power surges covered from day one. Real experts are available 24/7 to help with set-up, connectivity issues, troubleshooting and much more.
- Easy Claims Process: File a claim anytime online or by phone. Most claims approved within minutes. We will send you an e-gift card for the purchase price of your covered product. In some instances, we will replace or repair it.
- Product Eligibility: Plan must be purchased with a product or within 30 days of the product purchase. Pre-existing conditions are not covered.
- Terms & Details: More information about this protection plan is available within the “Product guides and documents” section. Simply click “User Guide” for more info. Terms & Conditions will be available in Your Orders on Amazon. Asurion will also email your plan confirmation with Terms & Conditions to the address associated with your Amazon account within 24 hours of purchase.
- Buy a lot of stuff on Amazon? Tons of items eligible for coverage, from the latest tech like Laptops, Game Consoles, TVs, Phones, and Cameras to major appliances, sporting goods, tools, toys, personal care, furniture, and more.
- Accidents Happen. That’s why for your portable products we cover accidental damage from handling such as drops, spills and cracked screens. We also cover electrical and mechanical malfunctions, power surges, and wear and tear.
- Past and Future Purchases covered. 30 days after you are enrolled, all eligible past purchases (up to 1 year prior to enrollment) and future eligible purchases made on Amazon will be covered by your plan as long as you are enrolled.
- Fast, easy claims. Frustration-Free claims, with most filed in minutes. We will fix it, replace it, or reimburse you with an Amazon e-gift card for the purchase price of your product (excluding tax). File at Asurion.com/amazon.
- No Hidden Fees. For just $16.99 a month + tax you’re covered for up to $5,000 in claims per 12-month period. *THIS PROGRAM IS MONTH-TO-MONTH AND WILL CONTINUE UNTIL CANCELED* Coverage for all products ends 30 days after the plan is canceled. Cancel any time.
Add to your order
- Coverage for accidental damage including drops, spills, and broken parts, as well as breakdowns (plans vary)
- 24/7 support when you need it.
- Quick, easy, and frustration-free claims.
Amazon Prime Free Trial
FREE Delivery is available to Prime members. To join, select "Try Amazon Prime and start saving today with FREE Delivery" below the Add to Cart button and confirm your Prime free trial.
Amazon Prime members enjoy:- Cardmembers earn 5% Back at Amazon.com with a Prime Credit Card.
- Unlimited FREE Prime delivery
- Streaming of thousands of movies and TV shows with limited ads on Prime Video.
- A Kindle book to borrow for free each month - with no due dates
- Listen to over 2 million songs and hundreds of playlists
Important: Your credit card will NOT be charged when you start your free trial or if you cancel during the trial period. If you're happy with Amazon Prime, do nothing. At the end of the free trial, your membership will automatically upgrade to a monthly membership.
$126.01$126.01
Ships from: Amazon Sold by: Smoove Sales LLC
$31.50$31.50
Ships from: Amazon Sold by: Amazon Resale
- 7 VIDEOS
Image Unavailable
Color:
-
-
-
- To view this video download Flash Player
Motorola MB7621 Cable Modem | Pairs with Any WiFi Router | Approved by Comcast Xfinity, Cox, and Spectrum | for Cable Plans Up to 900 Mbps | DOCSIS 3.0
Return this item for free
We offer easy, convenient returns with at least one free return option: no shipping charges. All returns must comply with our returns policy.
Learn more about free returns.- Go to your orders and start the return
- Select your preferred free shipping option
- Drop off and leave!
Return this item for free
We offer easy, convenient returns with at least one free return option: no shipping charges. All returns must comply with our returns policy.
Learn more about free returns.- Go to your orders and start the return
- Select your preferred free shipping option
- Drop off and leave!
Purchase options and add-ons
Brand | Motorola |
Internet service provider | Time Warner Cable, Xfinity, Charter Spectrum, Cox |
Connectivity Technology | Ethernet |
Compatible Devices | Personal Computer |
Product Dimensions | 7.25"L x 2.25"W x 7.88"H |
About this item
- Model MB7621 is recommended for actual cable Internet service speeds up to 650 Mbps. Wirecutter rates this “the best modem for most people.” A Full-Band Capture Digital Tuner ensures faster, more reliable Internet.
- This cable modem's 1 Gigabit Ethernet port connects to a WiFi router, computer, HDTV, game station, or streaming video device. Great for use with Whole Home WiFi or Mesh networks like eero, Google WiFi, and Orbi. (This cable modem does not have a built-in wireless router or telephone call capability. The Motorola MG7315, MG7540, MG7550, and MG7700 have a built-in wireless router.)
- Requires cable Internet service.Approved by and for use with Comcast Xfinity and Xfinity X1, Cox, Charter Spectrum, Time Warner Cable, BrightHouse, CableOne, SuddenLink, RCN, and other cable service providers. Eliminate cable modem rental fees up to 156 dollars per year. (Savings are shown for Xfinity and vary by cable service provider. No cable modem is compatible with fiber optic, DSL, or satellite services from Verizon, AT&T, CenturyLink, Frontier, and others. Model MB7621 has no phone jack.)
- Setup is fast and easy using the quick start guide.
- Attractive, compact design minimizes shelf space, improves cooling, and extends product life while looking great in any home or office. A 2-year warranty plus rugged lightning and power surge circuits protect your investment.
Buy this product as Renewed and save $46.01 off the current New price.
(52)
Works and looks like new and backed by the Amazon Renewed Guarantee
Consider a similar item
Frequently bought together
Customers who bought this item also bought
Top Brand: Motorola
From the brand
What's in the box
Compare with similar items
This Item Motorola MB7621 Cable Modem | Pairs with Any WiFi Router | Approved by Comcast Xfinity, Cox, and Spectrum | for Cable Plans Up to 900 Mbps | DOCSIS 3.0 | Recommendations | |||||
Try again! Added to Cart | Try again! Added to Cart | Try again! Added to Cart | Try again! Added to Cart | Try again! Added to Cart | Try again! Added to Cart | |
Price | $126.01$126.01 | $219.00$219.00 | -6% $187.13$187.13 List: $199.99 | $59.95$59.95 | $44.41$44.41 | $169.00$169.00 |
Delivery | Get it as soon as Wednesday, Jan 22 | Get it as soon as Wednesday, Jan 15 | Get it as soon as Wednesday, Jan 15 | Get it as soon as Wednesday, Jan 15 | Get it Jan 21 - 28 | Get it Jan 16 - 21 |
Customer Ratings | ||||||
Sold By | Smoove Sales LLC | Amazon.com | Premier LogiTech | W&Y Inspiration | Newfangled Networks | BlueDealz |
connectivity tech | Ethernet | Ethernet | Wi-Fi, Ethernet | Gigabit Ethernet | coaxial cable, Ethernet | Ethernet |
ethernet ports | 1 | 2 | 4 | 1 | 1 | 2 |
number of ports | 1 | 2 | 4 | 1 | 4 | 2 |
data transfer rate | 1000 megabits per second | 2.5 gigabits per second | 1 gigabits per second | 300 megabits per second | 686 megabits per second | 2 gigabits per second |
max downstream rate | 1000 megabits per second | 2500 megabits per second | 1000 megabits per second | 680 megabits per second | 686 megabits per second | 2000 megabits per second |
max upstream rate | — | 444 megabits per second | — | 123 megabits per second | 143 megabits per second | 232 megabits per second |
modem type | cellular | cable | cable | cable | cable | cable |
internet service provider | Xfinity, Cox, Charter Spectrum, Time Warner Cable | Comcast Xfinity, Cox, Spectrum | Xfinity, Cox | xfinity, spectrum, cox, optimum | xfinity, spectrum, cox, optimum | Cox, Spectrum, Xfinity |
Product guides and documents
Product Description
The smart choice for your cable Internet service
Eliminate monthly cable modem rental fees – Typically saves 168 dollars per year in Xfinity cable modem rental fees. Actual savings depend on your service provider.
800+ Mbps – Maximum actual Internet download speed
GigE Ethernet port – For a high-speed wired connection to any router, computer, or other Internet-capable device.
Connect any WiFi router you choose
Plugs easily into any router for shared Internet access by all your WiFi and Ethernet-capable devices. This flexible approach lets you pair this cable modem with any router you choose for your WiFi needs, including a mesh router or gaming router.
If the MB7621’s Ethernet port isn’t used for a router, it can plug into a computer, HDTV, game station, or other Ethernet device.
Compatible with Most Cable Providers
Certified by Comcast Xfinity, Cox, Charter Spectrum, and other cable providers.
* Not compatible with Verizon, AT&T, CenturyLink, and other fiber optic, satellite, or DSL services.
Fast Internet Speed
Connects fast with just 3 connections - power, coax cable, and Ethernet.
Supports internet plans with speeds up to 900 Mbps
For other service providers, supported service speeds are similar to Comcast.
MB7220 | MB7420 | MB7621 | MB8600 | MB8611 | |
Customer Reviews |
4.3 out of 5 stars
4,310
|
4.4 out of 5 stars
6,886
|
4.4 out of 5 stars
29,227
|
4.4 out of 5 stars
29,227
|
4.4 out of 5 stars
29,227
|
Price | $78.98$78.98 | $21.04$21.04 | $126.01$126.01 | $197.77$197.77 | $187.15$187.15 |
Product Type (This table only includes cable modems with NO built-in WiFi router) | 8x4 Cable Modem | 16x4 Cable Modem | 24x8 Cable Modem | DOCSIS 3.1 plus 32x8 3.0 Cable Modem | DOCSIS 3.1 plus 32x8 3.0 Cable Modem |
DOCSIS Channel Bonding | 8x4 DOCSIS 3.0 | 16x4 DOCSIS 3.0 | 24x8 DOCSIS 3.0 | DOCSIS 3.1 plus 32x8 DOCSIS 3.0 | DOCSIS 3.1 plus 32x8 DOCSIS 3.0 |
Certified for These Cable Internet Services. Typically Works with Many Others. | Comcast Xfinity, Cox, Spectrum, Sparklight (CableOne), WOW! | Comcast Xfinity, Cox, Spectrum, Suddenlink, Sparklight (CableOne) | Comcast Xfinity, Cox, Spectrum, Suddenlink, Sparklight (CableOne) | Comcast Xfinity, Cox | Comcast Xfinity, Cox |
Recommended by Comcast Xfinity for Internet Service This Speed Tier or Below | 200 Mbps | 300 Mbps | 800 Mbps | 1000 Mbps | 2500 Mbps |
Maximum Internet Download Speed (Actual speeds are lower) | 343 Mbps | 686 Mbps | 1000+ Mbps | 1000+ Mbps | 2500 Mbps |
Built-in WiFi Router | No | No | No | No | No |
Gigabit Ethernet Ports | 1 | 1 | 1 | 1 | 1 (2.5 Gbps) |
Works With Any WiFi Router That Has an Ethernet WAN port | ✓ | ✓ | ✓ | ✓ | ✓ |
Telephone Ports | No | No | No | No | No |
What Modem/Router Product is Most Similar to This Modem-Only Product? | Yes, MG7315 | Yes, MG7540 | Yes, MG7700 | None, but works with any router that has an Ethernet WAN port | Yes, MG8702 |
Videos
Videos for this product
2:13
Click to play video
4 Years Later With Motorola MB7621 Cable Modem
JR Reviews
Videos for this product
0:57
Click to play video
Everything you NEED to know about this Motorola Modem!
Joseph Good
Videos for this product
1:35
Click to play video
Skip the rental modem and own your Internet!
Forever Joven
Videos for this product
4:26
Click to play video
Setting Up The Motorola MB8611 DOCSIS 3.1 Cable Modem
Distractor_Beam
Videos for this product
1:02
Click to play video
This Modem is Great and Will Save you from monthly fees!
Chadeveryday
Videos for this product
0:30
Click to play video
Stop renting your modems from the cable companies
JOE GOODE
Videos for this product
0:51
Click to play video
Motorola MB8600 Cable Modem + AC2600 Smart Wi-Fi
Milagros Mabanglo
Product information
Product Dimensions | 7.25 x 2.25 x 7.88 inches |
---|---|
Item Weight | 1.12 ounces |
ASIN | B077BL65HS |
Item model number | MB7621 |
Batteries | 1 9V batteries required. |
Customer Reviews |
4.4 out of 5 stars |
Best Sellers Rank | #15,264 in Electronics (See Top 100 in Electronics) #23 in Computer Networking Modems |
Is Discontinued By Manufacturer | No |
Date First Available | December 20, 2017 |
Manufacturer | MTRLC LLC |
Warranty & Support
Feedback
Motorola MB7621 Cable Modem | Pairs with Any WiFi Router | Approved by Comcast Xfinity, Cox, and Spectrum | for Cable Plans Up to 900 Mbps | DOCSIS 3.0
Share:
Found a lower price? Let us know. Although we can't match every price reported, we'll use your feedback to ensure that our prices remain competitive.
Where did you see a lower price?
Fields with an asterisk * are required
Looking for specific info?
Customer reviews
Customer Reviews, including Product Star Ratings help customers to learn more about the product and decide whether it is the right product for them.
To calculate the overall star rating and percentage breakdown by star, we don’t use a simple average. Instead, our system considers things like how recent a review is and if the reviewer bought the item on Amazon. It also analyzed reviews to verify trustworthiness.
Learn more how customers reviews work on AmazonCustomers say
Customers find the modem easy to set up and activate. They appreciate its fast internet speeds, good signal quality, and value for money. However, some customers have experienced connectivity issues where the connection drops intermittently.
AI-generated from the text of customer reviews
Customers are satisfied with the modem. They mention it works well with their WiFi router and has no issues. It activates smoothly, connects easily to Xfinity, Spectrum, and other providers. The single port works well at 800 GBPS, and Alexas work in every room.
"...That's it. It makes a connection. And hasn't failed since I got it a month or so ago...." Read more
"...UPDATE JUL2018: The MB8600 is still running like a champ. No issues...." Read more
"...Activation worked fine. I did get a dead on arrival modem the first time. I guess the quality check in production is not quite there...." Read more
"...modem in place with my Erro wifi router and these two work fantastic together!..." Read more
Customers find the modem setup easy. They mention it works with WOW in SE MI, there are good YouTube instructionals on installing this modem, and it installs and activates quickly and easily. It's a plug-and-play device, so all they had to do was connect it to their coaxial cable.
"...Up and running within 15 minutes, No call to Comcast. [..." Read more
"The Xfiniity compatible Modem was super easy to set-up following the Quick Start guide included in the box...." Read more
"...I got the Motorola AC2600 4x4 WiFi Smart router. Installation of both devices was very easy. Literally, plug and play...." Read more
"Arrived o n schedule, installed and working fine. (16 Hours)." Read more
Customers appreciate the modem's fast internet speeds and seamless compatibility. They find the setup simple, quick, and easy. The modem has the ability to extend those speeds into their home network via port channeling. It runs smoothly and connects within 5 minutes.
"...Turn it on. It goes through the startup cycle. Takes a few minutes to connect like they all do and that's it. Set it and forget it...." Read more
"...The MB8600 synced up with Comcast quickly (according to the lights); but, I could not obtain an Internet connection...." Read more
"...UPDATE: This modem continues to run so smoothly I don't know it is there except when I look across the room at its satisfying cluster of blinking..." Read more
"...This modem got connected within 5 minutes and I got a public IP through DHCP from Comcast. Activation worked fine...." Read more
Customers enjoy the modem's signal quality. They mention it's great and has given them no issues. The modem offers bonded internet connections, the latest cable modem service standard, and is future-proof. Some praise the device for its eye-popping Wi-Fi boost and easy setup.
"...have any complaints, and can only praise the device for its eye-popping Wi-Fi boost, for which I have no good explanation...." Read more
"...up in place of my existing modem and it promptly synced up and indicated connectivity...." Read more
"...purchase to carry us for years to come and not compromise our connection compatibility...." Read more
"...Comcast quickly (according to the lights); but, I could not obtain an Internet connection...." Read more
Customers appreciate the modem's value for money. They say it covers up to 600Mbps and is half the price of the gigabit model. Many find it a good upgrade from their previous Motorola SBG6580, saving them monthly modem rental fees. Some customers say it works as advertised and is a good choice for some uses.
"...This literally pays for itself in 16 months, and most people will have their Internet connection for many times that long, and time flies...." Read more
"...For this price point, a bit more functionality can be expected. 2. The modem provides 4, not one, but four Local Area Network connections...." Read more
"...Yes I would recommend this product for the long-haul investment...." Read more
"Pricy, but worth it. Motorola is the go to brand for high quality...." Read more
Customers have mixed opinions about the modem's reliability. Some find it reliable and solid, with a speedy connection. Others report issues like random crashes, outages lasting for minutes, or shaky performance.
"...Wow. I really like this modem. This is a barebones rock solid dead simple workhorse...." Read more
"...The modem worked amazingly for three weeks until it just kept crashing at random once every so many minutes or hours...." Read more
"...I believe this to be a well designed, solid modem...." Read more
"...To-the-point, the Motorola’s modem’s were all Connectivity, Stability, Compatibility Total..." Read more
Customers have mixed opinions about the modem's compatibility. Some say it works well with most broadband providers and almost all WiFi routers. Others report issues with the modem not working with their network, including Comcast dropping signal and having to reboot the system to reconnect.
"...This should be good for about 3-5yrs. 3. A good compatible router...." Read more
"...They quickly stated that it is not compatible with their network which I promptly told them your website said it's for the fastest internet services..." Read more
"...I did lots of research and found the MB8611 was the best fit for my setup and future service upgrades...." Read more
"Easiest cable modem I've deployed...." Read more
Customers are unhappy with the connectivity of the modem. They report issues like connection drops, signal loss, and intermittent connectivity. The wired speed is 438/22 while the wireless speed is less impressive at 41/4. There are also reports that the modem can have temporary problems and only provide connectivity to a single device.
"...And strong signals, persistent signals and people who are more sensitive or have immunity issues can be more vulnerable..." Read more
"...But, a temporary modem problem can sometimes happen, I think that is not unusual for anybody, so I already knew what to do: 1...." Read more
"...So it should work right? Nope there was still no access to the internet...." Read more
"...up to 4 smart phones, 3 laptops, 2 iPads and the smart tv all running with no connection issues. *..." Read more
Reviews with images
Very satisfied with the MB8611 after 2 yrs
Top reviews from the United States
There was a problem filtering reviews right now. Please try again later.
- Reviewed in the United States on March 27, 2018Size: DOCSIS 3.1 (1 Gbps Ethernet Port)Verified PurchaseWARNING: THIS IS A LONG REVIEW, BUT I MAY HAVE SOME ANGLES ON THIS OTHERS DON'T :-)
Wow. I really like this modem. This is a barebones rock solid dead simple workhorse.
It's got a plug for the cable and one ethernet (RJ-45) port out and I think an on/off switch.
That's it. It makes a connection. And hasn't failed since I got it a month or so ago.
All I had to do was call my ISP and give them the MAC address (on the sticker on the device)
and they updated their tables and that was it. Turn it on. It goes through the startup cycle. Takes a few minutes to connect like they all do and that's it. Set it and forget it.
What prompted me to get it, is I don't like having to rent the modem from the ISP @ $10.00/mo forever. This literally pays for itself in 16 months, and most people will have their Internet connection for many times that long, and time flies. So it's a good investment.
It doesn't have phone connection like the ISP's modem did. So I called the company/provider that owns copper phone lines in the area and ordered landline service. I'm a nerd/techie and don't care what people say about landlines being for old fogeys, it's like having a backup generator ... I know I can use that landline if the power goes out or if the cell tower gets overwhelmed (too many calls or cell traffic at once), or there's radio interference in the area. Technically cable phone is a 'land line' (hardwired cable connection to provider) and the battery backup in the modem (which the ISP charges more for), could give you emergency phone service in an outage, but a cable phone connection can (and does) fail for more reasons than copper wire phone service does. (Those copper wire connections are called POTS - which stands for Plain Old Telephone Service), and copper wire phones are the most reliable.
Having a separate modem from a router is optima for a few of reasons... Generally hybrid units of anything do everything okay, but nothing optimally (for example combination modem-router units like my ISP rents out). Better to keep the modem separate from the router. Then you can swap either out independently to upgrade as needed, disrupting less of your own network configuration doing so, and also help avoid a single point of failure. Plus, you might be able to score a router in a pinch on shorter notice than a cable modem if the router is the component that fails. Then you can choose the router you actually like, for whatever reason, and don't have to settle for whatever bundling du jour your ISP decides is right for you (even if it isn't).
That gets me to the other point. What DID the ISP decide was right for me (but wasn't)?
For awhile my ISP modem connection was dropping briefly in the middle of the morning. My computer came back up connected to the ISP's 'general public' wi-fi connection to their router which did not work for me and I'd have to keep manually switching back to my own internal Wi-Fi LAN (network). That was not only inconvenient but it forced me to investigate was was going on there.
I learned my ISP gives lets passersby connect to their rental-modem's Wi-Fi signal, without giving me any way to disable that service! That really pissed me off to learn. The idea is that people driving around who have accounts with the provider can get internet access around the neighborhoods. If I was a passerby, that could really help me, so at first glance maybe 'why not, be a good samaritan'.
But wait! There may be more too it than that.
Besides the fact that I don't like it (for good reason), they give me no control over that 'feature'!
And I see some downsides. What's good for the ISP isn't necessarily optimal for me.
What I don't like about that 'service' is that one or more people could sit outside and suck down bandwidth (e.g. slow my connection down), unbeknownst to me. It also might cause the unit to use more energy and put out a stronger wi-fi signal than it needs to. Which health conscious people are well advised to be aware of. Wi-Fi is radiation. Not strong and may not ruin your life, but it is a stressor at a cellular level, this is known. And strong signals, persistent signals and people who are more sensitive or have immunity issues can be more vulnerable (headaches, sleep disruption, or worse). But I like Wi-Fi so I settle for whatever unknown health consequences I may not be aware of.
Also it makes me wonder if a hacker might be able to use it as an additional point of access to my home network.
I also wonder if it's 100% clear to law enforcement at first glance who might be visiting sites or doing something nefarious from the connection point. Might it look like the owner is doing something that a passerby did (and even if they can sort it out later, what if it takes awhile to figure out and they make a bad assumption?)
Anyway, I don't have that problem with this modem and I'm just much happier with it all the way around.
Plus it's blazingly fast.
- Reviewed in the United States on July 5, 2017Size: DOCSIS 3.1 (1 Gbps Ethernet Port)Verified PurchaseReceived the Motorola DOCSIS 3.1 cable modem on-time from Amazon. Up and running within 15 minutes, No call to Comcast.
Motorola Ultra Fast DOCSIS 3.1 Cable Modem, Model MB8600, plus 32x8 DOCSIS 3.0, Certified by Comcast XFINITY
Paper instructions were in the box and also online. No firmware available for prior update. I had previously confirmed that this device is acceptable to Comcast. Before buying any network device, always check that your ISP supports the device you plan to buy. Unacceptable for us to rate an item poorly if its is not compatible with your stuff...
I replaced a Cisco - Linksys model DPC3008 DOCSIS 3.0 cable modem purchased thru Amazon for $90 exactly five years ago. It has never failed. I would have paid Comcast say $10 / month to lease their inferior modem for the last 60 months, using the roughly $510 savings to enjoy Comcast "Blast" speeds not supported by their leased modem. I viewed this purchase as another future-proof, leading edge decision to replace a 5-year old $90 device. I did not expect a speed increase. Here is why.
If I log into my Comcast account and search for upgrades for my Internet service, there is only a fiber option. I am maxed out at a supported wire speed of "150 mbps". I attained that with the 5-year old DOCSIS 3.0 device. So, Comcast does not yet offer DOCSIS 3.1 service here; and, they will not reveal that to customers. I searched for a couple of hours for that revelation. The new MB8600 has a connect LED the turns blue with a 3.1 connection else stays green to confirm 3.0 per the instructions. Mine is green now. So, "NO", Comcast has not brought DOCSIS 3.1 to my area.
Follow the instructions. They work. I suggest however that you perform a broadband speed test prior to switching out your old cable modem. I also suggest you have your Comcast account number from a bill and ensure your Comcast account has your current phone number. NOT clearly said; but, I also suggest that you eliminate your network's switches / routers / Wi-Fi and simply Ethernet connect to any one of the four gigabit Ethernet ports on the back of the MB8600. I used port one.
The MB8600 synced up with Comcast quickly (according to the lights); but, I could not obtain an Internet connection. I'm guessing Windows 10 Pro simply was trying to protect me from a new intrusion. This is not a Windows 10 / Microsoft Edge issue. Solution: delete all network settings, reboot and there it was, Comcast activate. Enter your data and your MB8600 will reset. Once completed, I was online within 15 minutes. But, the speeds I had before were faster than now. Guess that my firmware had not yet been updated by Comcast.
The label on the bottom of the MB8600 has an IP address, user name and password. I logged in and saw that the modem had provisioned to DOCSIS 3.0 with only one channel down and three channels up, far below its capacity in 3.0. You resolve this by pressing in the RESET button on the back of the MB8600 for several seconds till the lights flash. After, I now have 24 channels down and three channels up. I then retested my speeds to confirm that I was exceeding the Comcast Extreme 150 service level I am paying for: 180 mbps down / 24 up. That is a roughly 10% improvement still on DOCSIS 3.0. Again, Comcast here does not seem to support any faster wired speed than 150 mbps, and deeper level of DOCSIS 3.0 than 24X3 and no DOCSIS 3.1, now, no DOCSIS 3.0 32x4 either. I can hope but AOL is perceived as "high tech" here...
I hate contacting Comcast customer service since I always feel as if I am training them. I may invest the day it will likely take to get Comcast to remotely re-provision my interface with them. Maybe not.
Satisfied that I was connected as well as I could, I then moved on to reconnect my router for its Wi-Fi and more importantly for its added Trend Micro security not offered by the MB8600 since it is not a router, its a cable modem. My configuration is MB8600 to an Asus router with 4 gigabit ports and Wi-Fi AC2400. One wired port feeds a dumb Gigabit switch supporting five devices. A second wired port supports my Microsoft Book. I'm a retired IT guy so I avoid wireless connections excepting my cell.
Yes, I have my cable modem, router and PC powered thru an uninterruptable power supply. The MB8600 documentation states that its power supply is resistant to power surges. We have afternoon storms all summer. Its fun to continue surfing while neighbors are dark; yet, my Comcast and DirecTV both work fine with a UPS power supply. Good that Motorola upgraded to some surge protection; but, I want that and sine wave continuous power. For your consideration....
The MB8600 has been connected for roughly six hours. It is barely warm and only at its top. Off to a good start.
UPDATE JUL2018: The MB8600 is still running like a champ. No issues. Comcast finally has some competition from Century Link with its fiber optic Gigabit offering wired into my neighborhood just days before hurricane Irma. I signed up for it since its cost was just a minor bump for gigabit from 150 mbps. A few months ago, the green DOCSIS icon turned from green to blue indicating that Comcast had turned on version 3.1 but; I was provisioned for 150 Mbps and did not see a speed jump. Nine months later, still no Century Link offer.
Regardless, I opted to move to a different home. Unfortunately an older neighborhood with no Century Link fiber optic. But Comcast does offer Gigabit speed at a higher price. Comcast's cables here are 30 to 40 years old unfortunately.
I've been with Comcast for well more than 8 years. This was the first move / install that was completed correctly the first time. The tech clocked 960 Mbps at the MB8600 down. My PC sees less speed (580 to 870 down) with a reliable 40 Mbps up. The MB8600 performs as advertised. All 32 downstream channels and 4 upstream channels are locked.