Have your own modem with Gigabit service and not getting that speed?

Love to know if you find a way to resolve this. I suspect I may be having a similar issue with an owned Netgear CM1200 modem.

Hmm... I reset my modem thru Xfinity, but I'm not seeing any messages about config files being sent.

I have little faith in tech support as well... the guy they sent out to my house tried to go to speakeasy to do a speed test, but I had to show him where the "s" and "a" keys were cuz WASD keys are worn off on my keyboard.  That quickly tempered my expectations.

my modem listens on 192.168.100.1 regardless of my network range. i can check logs on it that way via browser, looks like this

---

@Bitness wrote:

and we cant resolve this, xfinity controls this 100%. You just cant talk to any tech person at that level who understand any of this right now. I cant even get level 1 support to stop confusing my modem with a router. 

---

You could try asking for a tier 2 rep and / or a supervisor.

Are you sure you dont work for comcast? Should i reboot my modem too? Of course I asked for tier 2 but was told they are not able to forward calls to tier 2 due to high call volume. i have a ticket # and have been waiting for a callback for days on it. Before that i had an inside tech who said it was an outside issue and then later an outside tech who said it was fixed outside, i said i have same speed, he said give it a few mins and left. So i have been around the block with support and none of them even thought to check my modem config even though from the start i kept saying you have not configured my modem for gig, only 300mbs. When i finally found the proof in the log i asked support if they wanted the erorr msg or the config file name, they said no. This is why im venting here. i know this will eventually get fixed but right now there is nothing i can do other than wait for comcast to call. My suggestion was to just credit my account the 20$ extra that gig was supposed to cost me this month and I would call back in 30days. Comcast said they cant do that and instead i should call back every couple of days during ther month to let them know "its still an issue"

No. I don't work for them. Just trying to help you. And I don't care for your sarcasm............ I'm not a mind reader...... I can't know what you've done.... Have a ball pal...............

I'm having the same issues with my Netgear CM 1000 v2. I get 300 - 400 mbps with my gig plan. The agent said it was because the modem has Docsis 3.0 and Docsis 3.1 on it and he said that I need a model that ONLY has Docsis 3.1 inorder to get the gig speed I am now paying for. He was super unhelpful, and even though I told him the CM1000 v2 model is on their own website saying its compatible he insisted I was wrong and that I needed to call Netgear to disable Docsis 3.0 on the modem. Which I cant.

I guess Ill have to attempt to call Comcast again and wait another 2 hours for another untrained agent to help me.

Basically comcast doesnt support 3rd party devices. I know its super confusing when they recommend 3rd party devices to you on their website and have a nice page where you can enter your zip and speed to see compatible devices. The joke is on the customer of course becasue that just means your free to buy one and plug it in but chances you get gig speeds are slim and comcast will not offer any assistance. Ive spent hours and hours and hours on this. Here is my latest chat with comcast from today. waited an hour to get a person on chat.  This was my favorite part but read the whole thing for the full experience

i would like to speak with your manager
ME: 3:48:07 PM
I understand that you want to talk to my manager, but I am willing to provide to all the help that you needed.

COMCAST: 3:50:02 PM

here is the whole thing

Connecting from Xfinity Assistant
ME: 1:28:52 PM
3-25-2020, 12:23:44 Error(4) "SW upgrade Failed after download - Incompatible SW file"3-25-2020, 12:23:42 Notice(6) "SW Download INIT - Via Config file d11_m_sb8200_gigabit_c01.cm"
ME: 1:30:13 PM
Don't worry. Your sensitive data has been masked.
my sb8200 modem rejects your config
ME: 1:30:24 PM
says its invalid. this causes the settings for my gig service to fail and fallback to previous service level
ME: 1:30:55 PM
d11_m_sb8200_gigabit_c01.cm is the file your sending me
ME: 1:37:14 PM
ok so after waiting in the chat line from 350 down to 50 now its just says be prepared to wait longer. no idea when this chat will be availabale or if ill be here but it would be great if you could tell anyone at comcast who understands the provisioning process that my config d11_m_sb8200_gigabit_c01.cm is bad and i will never get the service Im being billed for until a valid config is applied to my modem
ME: 2:03:10 PM
please update my account to reflect that i am still not getting gig service and i am requesting a credit on my next bill for all the days this month that i am not getting the service i am paying for
ME: 2:04:45 PM
You are now chatting with COMCAST:
Hello, thank you for contacting Xfinity Support.

COMCAST: 2:14:19 PM
hello
ME: 2:14:24 PM

Thank you for patiently waiting on the queue.
COMCAST: 2:14:41 PM
ty, i have provisioning issue. if you got what i typed while waiting it should describe my issue
ME: 2:15:15 PM
basically my sb8200 modem says your config file is invalid
ME: 2:15:36 PM
and this is the config the sets my modem speed
ME: 2:15:51 PM
so my upgrade from 300mbs to 1000mbs never actually happened on my end
ME: 2:16:30 PM
already had tech onsite, line is gig ready
ME: 2:16:45 PM
already had tech outside, said outside line is ready
ME: 2:16:55 PM
any of that making any sense?
ME: 2:18:07 PM
Hi, please allow me 2-3 minutes to review all the information you provided.
COMCAST: 2:18:46 PM
no problem
ME: 2:18:51 PM
Thank you!
COMCAST: 2:19:46 PM
Thank you for patiently waiting.
COMCAST: 2:21:41 PM
I understand that you have a provisioning issue, we will be troubleshooting the issue. If in case these would not work, we will exhaust all options that we have to permanently resolve your concern.
COMCAST: 2:22:43 PM
ok
ME: 2:23:53 PM
have restarted the modem many many times already over past 2 weeks
ME: 2:24:06 PM
Thank you for doing basic troubleshooting on your end.
COMCAST: 2:24:47 PM
I would like confirm, are you having slow connectivity or intermittent connectivity issue?
COMCAST: 2:24:48 PM
ill say again. i ordered 1000Mbs service. You started charging me for the gig service and never updated my modem from previous settings of 300mbs
ME: 2:25:40 PM
when you reboot my modem, it downloads your config as shown in the log...
ME: 2:26:51 PM
SW Download INIT - Via Config file d11_m_sb8200_gigabit_c01.cm
ME: 2:26:52 PM
then modem rejects the config as invalid...
ME: 2:27:11 PM
SW upgrade Failed after download - Incompatible SW file
ME: 2:27:20 PM
there should be notes on my account already, can i escalate to tier2 or a manager?
ME: 2:28:30 PM
Oh I see, thanks for the information you provided. We'll go ahead and troubleshoot the issue.
COMCAST: 2:28:34 PM
To further assist you, please provide me your Full Name.
COMCAST: 2:28:40 PM
ME:
ME: 2:28:45 PM
Thanks, Justin!
COMCAST: 2:30:44 PM
I have the numbers of your street address as “65”, is this the account you’re chatting in about?
COMCAST: 2:31:05 PM
yes
ME: 2:31:11 PM
Perfect! Please allow me 2-3 minutes to access your account.
COMCAST: 2:33:09 PM
ok should be notes about this on there already
ME: 2:33:46 PM
Thanks for patiently waiting, currently reviewing your account. I'll also take a look at the notations.
COMCAST: 2:36:12 PM
By the way, I can see here that here has been a notation on your account regarding to connectivity issue.
COMCAST: 2:42:19 PM
We will be troubleshooting your modem first
COMCAST: 2:42:51 PM
ok i feel like everything we will be doing has been done before when i called support
ME: 2:43:17 PM
are you planning on doing something new?
ME: 2:43:23 PM
im afraid your going to reboot my modem and kick me from this chat
ME: 2:45:08 PM
are you familiar with this configd11_m_sb8200_gigabit_c01.cm ?
ME: 2:45:44 PM
Don't worry. Your sensitive data has been masked.
really need someone who can speak to why thats invalid
ME: 2:46:05 PM
i cant see it
ME: 2:46:07 PM
I understand that you already had a troubleshooting with the previous support. But nothing to worry, once you keep your window open it won't disconnect you from the chat.
COMCAST: 2:47:23 PM
I would like to clarify -"configd11_m_sb8200_gigabit_c01.cm" where can you see this error?
COMCAST: 2:48:22 PM
the event log of my sb8200 arris modem
ME: 2:48:36 PM
can i escalate to tier2? i am fine waiting however long that takes
ME: 2:48:59 PM
I understand the urgency of having your Internet connectivity fix, please allow me 2-3 minutes to provide you option that can permanently resolve this issue.
COMCAST: 2:51:23 PM
ok that would be great
ME: 2:51:32 PM
Thank you!
COMCAST: 2:51:56 PM
Oh, by the way I would like to clarify. You mentioned that there was already a tech visited your address. Did the tech checked your connections inside the house?
COMCAST: 2:55:25 PM
yes 2 techs, 1 outside and one inside
ME: 2:55:40 PM
all good
ME: 2:55:42 PM
he pulled 950mbs from the line
ME: 2:55:49 PM
bypassing the modem
ME: 2:55:53 PM
everything appears to be good except the cm file you send my modem to configure it for gig service
ME: 2:57:07 PM
SW upgrade Failed after download - Incompatible SW file
ME: 2:57:34 PM
is the message i get from the modem log after it tries to apply your file mentioned above
ME: 2:57:50 PM
i bought this modem base on the xfinity supported devices page for my area and speed. its supported for gig speed
ME: 2:58:58 PM
Yes, I can see here that your modem is compatible with the Gigabit speed of Internet.
COMCAST: 2:59:35 PM
If you want, we can try for the last time to troubleshoot first the issue afterwards if it won't work. We will ask assistance from our higher tier support. Would that be fine with you?
COMCAST: 3:00:41 PM
what does troubleshooting consist of?
ME: 3:01:14 PM
will you do something different that just rebooting it and seeing if it works?
ME: 3:01:53 PM
i assure you it wont
ME: 3:02:01 PM
Troubleshooting your modem like sending signal to let it work within specification.
COMCAST: 3:02:27 PM
I would like to confirm, do you have personal router connected to your modem?
COMCAST: 3:02:53 PM
no
ME: 3:03:16 PM
i have a machine plugged directly into it for testing
ME: 3:03:24 PM
please go ahead and do any troubleshooting you need to
ME: 3:03:53 PM
I see. Is your device connected to your modem thru wired connection or wirelessly?
COMCAST: 3:05:23 PM
wired
ME: 3:05:30 PM
Yes, sure! I'll do my best to help you resolve your issue.
COMCAST: 3:05:53 PM
Also, are your other devices also having the connectivity issue with your internet?
COMCAST: 3:10:46 PM
these questions do not give me confidence
ME: 3:12:08 PM
the issue is you have to set my modem to gig speed with a proper config
ME: 3:13:02 PM
we dont need to talk about my home network or wireless or anything else that just complicates the issue. i have 1 machine plugged directly into the router
ME: 3:13:38 PM
and now i said router, i mean modem
ME: 3:13:59 PM
comcast guy plugs his device into my cable, gets gig speed. plugs in my modem, gets 300mbs
ME: 3:14:23 PM
this is 100% modem related
ME: 3:14:36 PM
right now my modem is configured to 300mb speed
ME: 3:14:51 PM
Yes, I understand that your modem is compatible with the speed, in that we are trying to do is to configure the reason of the error you're receiving on your end.
COMCAST: 3:15:25 PM
what on earth does that have to do with wireless or other computers on my network
ME: 3:16:02 PM
coax cable goes into modem, modem throws error. no need to go any farther into the LAN
ME: 3:16:25 PM
right, modem reboots. tries to download gigabit config file as shown in log entry...SW Download INIT - Via Config file d11_m_sb8200_gigabit_c01.cm
ME: 3:18:00 PM
Don't worry. Your sensitive data has been masked.
then second later, same modem log says the modem failed to apply that file
ME: 3:18:25 PM
SW upgrade Failed after download - Incompatible SW file
ME: 3:18:26 PM
there is no other hardware involved
ME: 3:18:36 PM
no router, no pc, nothing
ME: 3:18:41 PM
Alright. Thanks for all the information. I'm trying my best to help you on this issue. I will nitiate a reset to your modem.

Note: All your devices connected, including Voice over Internet Protocol (VoIP) services, will lose connectivity for a few minutes until the modem is back online.
Please keep your window open.
COMCAST: 3:19:59 PM
ok
ME: 3:20:14 PM
Thanks. Please allow me 2-3 minutes to initiate reset.
COMCAST: 3:22:48 PM
The browser is unable to connect to the chat server. Some messages may not have been delivered and you will not be able to send or receive new messages.
You are now reconnected with COMCAST:
same error
ME: 3:26:37 PM
SW upgrade Failed after download - Incompatible SW file
ME: 3:26:39 PM
I successfully initiate reset signal to your modem and an automated system check has identified the modem is online.
COMCAST: 3:26:48 PM
right same situation
ME: 3:27:58 PM
your gigabit speed config file is not valid for the sb8200
ME: 3:28:12 PM
ok is there anything else you want to try or can we escalate this?
ME: 3:30:56 PM
I understand really where you are coming from, If I were on your position I would also feel the same way having the error on your end.
COMCAST: 3:31:52 PM
speed test shows 300mbs
ME: 3:32:11 PM
I really appreciate your time, effort and patience with me all through out the process.

Since we already exhausted all possible steps that can resolve the issue, I will need to refer you to our Advance Wireless Team thru calling this number - 1-800-934-6489 to further assist you permanently resolving your issue.
COMCAST: 3:36:10 PM
ok, you know this isn't related at all to wireless right? AS in 100% wired network issue? is this just the name of tier2 support?
ME: 3:37:28 PM
Yes, you're correct that is just the name of our team that can further assist the issue.
COMCAST: 3:38:45 PM
**** 1-800-934-6489
COMCAST: 3:38:57 PM
can you have them call me? i assume if i call this number i will be on hold for long long time in a best case scenario
ME: 3:40:33 PM
I really understand that the team right now is receiving large volume of calls that is because of COVID crisis which is the number of agents receiving the call is decreasing also.

COMCAST: 3:43:57 PM
sigh guess what, robot want to reboot my modem
ME: 3:43:58 PM
i have wifi calling which will just drop me
ME: 3:44:06 PM
and if i say i dont want to reboot my modem it hangs up on me
ME: 3:45:04 PM
any other # i can call?
ME: 3:45:10 PM
I really appreciate it doing the possible solutions on your end.
COMCAST: 3:47:34 PM
i would like to speak with your manager
ME: 3:48:07 PM
I understand that you want to talk to my manager, but I am willing to provide to all the help that you needed.
COMCAST: 3:50:02 PM
The phone number I provided you is the only option that you can contact for us to further assist you on this matter.
COMCAST: 3:50:46 PM
it doesnt work
ME: 3:50:55 PM
If you don't mind me asking, is there anything else I can offer help for you?
COMCAST: 3:52:22 PM
i would like to speak to a manager
ME: 3:52:38 PM
Alright. Yes, sure I can refer you to my manager.
COMCAST: 3:53:24 PM
I can connect you over to my supervisor thru chat.
COMCAST: 3:54:15 PM
ok
ME: 3:54:21 PM
Thank you so much for your time and patience with me.
COMCAST: 3:55:16 PM
Please stay online and be connected to my supervisor who will assist you shortly.
COMCAST: 3:55:37 PM
ok

...SO, afte hours waiting and chatting i did get the manager. Guess what he did? He told me he needed to check something and rebooted my modem which disconnected my internet connection again and then he exited the chat. Back to square 1. So i called the tier 2 # provided. Let the robot reboot my modem...again. Waited for the callback for over an hour. When i spoke to someone they told me i had a modem issue. i said it was brand new because it was 2 weeks old. Comcast level 2 assured me there was a modem problem. I have a hot spare of all my hardware because i work from home and cat afford to be down if a modem goes bad. So i took brand new sb8200 out of the box while level 2 was on the phone and had them provision it from scratch.  Now im down to 200MB speed. seriously - you really cant make this up. And guess why comcast said my speed went down, you guessed it, it's big bad Arris and their modems of course. Logic has no effect on comcast support, the chances of three back to back bad modems are pretty slim but i digress. I did get a nice explanation from level 2 tech theat they also used to have a 3rd party modem at home but gave it up because comcast couldnt support it (yes the person trying to support me told me this). This all took more than 6 hours btw. Almost a full day of work blown. So next i went to Arris support...

Arris support was excellent. I waited about 30 seconds for a chat, and that chat lasted about 1 minute. Arris identified the issue with comcast immediately. the best part of this chat is this

I can totally assure that this device is capable of 1 Gbps.
What you told me about that you used other two modems gives us a hint of the issue.

in other words, the support at arris did what comcast support would't - listened to what i said and used logic and troubleshooting rather than just reading a script and rebooting things.

here is the full chat

Save Chat

Keyner A
Hi, Welcome to ARRIS Consumer Support. I’d be happy to assist you today.
Would you please confirm your product’s model number?
6:21:08 PM
Me
sb8200
6:21:17 PM
that what u need?
6:21:26 PM
Keyner A
Thank you, how can I help you today?
6:21:43 PM
Me
i ordered gigabit service thru comcast
6:21:56 PM
they were out, verified my lines ect. got gig speed from the cable. I use an sb8200 which is on their supported list for docsis 3.1 and gig speed
6:22:26 PM
long story short, modem doesn't go above 300mbs which was my old service. comcast said modem was bad
6:23:04 PM
bought a new one
6:23:07 PM
same issue, comcast said it was also bad
6:23:14 PM
now im on my 3rd modem, same issue. Comcast is telling me there is some issue with your modems and i have to contact you for support
6:23:45 PM
i dont really believe that but figured id see what you thought
6:24:06 PM
is there anything special i need to do to get gig speed with the sb8200?
6:24:19 PM
Keyner A
I see.
So, you're having slow speed issues and this is the third modem that you're trying. Correct?
6:25:19 PM
Me
yes
6:25:28 PM
all three modems top out at around 300mbs
6:25:41 PM
Keyner A
I understand, I apologize for the inconvenience. I'll be happy to assist you.
6:27:57 PM
Me
great, is there anything i can do to verify this modem is capable of gig speeds on my end?
6:28:47 PM
Keyner A
Yes, of course!
I can totally assure that this device is capable of 1 Gbps.
What you told me about that you used other two modems gives us a hint of the issue.
Let´s check the signal that´s coming from the Internet Service Provider to isolate any possible root cause for this issue.
6:30:32 PM
Me

6:31:12 PM
is that what you need?
6:31:17 PM
Keyner A
That's right!
Can you please send me also the Upstream Values?
6:31:33 PM
Me

6:32:02 PM
Keyner A
Perfect! Thank you!
Just allow me a couple minutes to double check those values!
6:32:17 PM
We just found the root cause of the Slow Speed.
The Power on the Upstream Channels is not between the acceptable levels (It must be above 45 dBmV) and that´s causing a delay on the Upstream Packages/Requests, therefore, slowing down the Downstream because of the loss of some information.
In these cases what we recommend is for you to contact your Internet Service Provider to fix the Cable Signal Levels because the Power on the Upstream Channels is not between the acceptable levels. We also recommend to ask for a Tier 2 agent for that.
6:35:10 PM
Me
ok
6:35:44 PM
thank you i guess i go back to comcast
6:36:17 PM
Keyner A
You are welcome! Is there anything else I can assist you with ?
6:36:41 PM
Me

so there you have it folks, comcast signal on the line is out of spec with my modem. I need to call comcast...again ....and wait....again... and get comcast to fix the signal even though this whole thing started with a comcast tech inside and another outside of my home who both verified that the line was good. Turns out, it is not. 

Wow reading that got my PTSD going.

I connected directly to my modem and was getting 528 mbps on my PC and on my surface using a USB gig network adapter, I got 600 - 700 mbps, not in the gig range yet, but better. Might just have to wait this out until COVID Is gone and a tech can come to my house.  I do get a drop off from my netgear cm1000 to my Netgear R8500 router. When I plug into the router I get 300-400 mbps. 

The tech told me to uninstall Docsis 3.0 on my modem, so I didnt have high hopes once I heard him say that. He also wouldnt re-provision it like I asked, I'll try to call back and see if I can get another agent to help me out as I should be getting higher speeds plugged directly into the modem. 

---

@Bitness wrote: ... Arris support ... The Power on the Upstream Channels is not between the acceptable levels (It must be above 45 dBmV) ...

---

Arris began saying this more than a year ago. I don't know why, because it's complete nonsense. Comcast's signal specs are the one posted in the Connection Troubleshooting Tips Forum article:

The upstream power levels are controlled by Comcast's equipment and do not need to be above 45 dBmV. In fact, many customers have service that works perfectly fine with upstream power levels below 45 dBmV. Some even operate with the upstream below 35 dBmV.

---

@Coreyhrpr wrote: ... The tech told me to uninstall Docsis 3.0 on my modem ...

---

More nonsense. It isn't possible or necessary for customers to "uninstall" DOCSIS 3.0 from their DOCSIS 3.1 gigabit modems. The rep (almost certainly not any sort of "tech") was incorrect.