Upgraded to gigabit internet, getting solid 32mbits

[db54]

Hey all!

I recently upgraded from the 200mb plan to a gb plan. With the old modem I saw my speeds increase a bit and was getting 150mb down/6 up on my mac and 57 on my iPhone.

I got my new modem yesterday (ARRIS TG3482G). There were some activation issues and they had to activate it on their side. Once it came back up I started getting 27-33 mbits, hovering steady around 32. It's been 12 hours, about 4 troubleshooting, reading this forum, going through the awesome gigabit troubleshooting video and checklist that are posted here, and 3 support sessions with comcast where they just keep rebooting and resetting my modem and giving me a number for a robot that reboots the modem and then never calls me back.

salient details:

1. I have rebooted and reset the modem, rebooted my machines, tried multiple computers etc.

2. I did a hard factory reset with a paper clip.

3. I connected and activated through the xfi app, through customer support twice, and through the website once after resets.

4. I am getting a SOLID 32mbit on 4 devices connected to wifi, on comcast's speed test. I am getting the exact same speed on my home pc (a monsterous gaming pc with a gigabit network adapter) wired directly using CAT6. Every device I try I get the same exact speed.

5. I am getting 40mbit up, which is much faster than it used to be, across all devices. That's faster than the download!

6. I am no longer using any of my own networking hardware. This is just their xfi router/modem combo.

7. My account says 1 gigabit and says the connection to the modem is fine. The support staff says it looks fine and that I am getting the 1gb bootfile. (lvl 1 support). I can't find a reference to this file anywhere in the router admin portal. I even dug through the html. This uses php, not the asp some of the routers seem to.

8. The admin portal at 10.0.0.1 shows 4 locked up streams and a whole bunch of locked down streams. One of them has 200 or so errors, the rest have 0 correctable/uncorrectable errors. I'm not sure the best way to past that here.

9. The important line: SNR seems mostly fine but I'm getting -14 -> -16 signal strength. I've seen conflicting reports on what the range should be here (most say -6 -> 6, but some references say -15 -> 15... 16 is out of range anyway). So possibly this is a signal strength issue. I replaced the cable to the wall and get no change. The cable is as tight as I can get it.

10. I followed the cable and it comes through my garage from the street, to the box on the side of the house, and arround and directly to the modem. No splitters except for a signal booster in the garage that is plugged into an outlet. The modem is the only device attached to the cable. They put this cable in about 8 years ago now and I could burst up to 200mbits with no problems on my old modem.

11. I am running winMTR and besides the one node that is blocking the packet type everything else shows 0 % loss and a latency around 12ms (range 2-40).

12. Support doesn't seem to even understand what I am saying and they have been friendly but ultimately not helpful. The last guy, Alfredo, kept insisting it was fixed and would just take more time. He kept trying to get off the chat, asking me to reboot over and over... says he reset my router but not my modem. No changes. It's been 16 hours since the modem and over a week since the upgrade to 1gbit. It really feels like they are walking through a script (besides Alfredo being a little abrupt I have to say the others were SUPER NICE though). As I said earlier the escalation number they gave me is a robot that resets my modem but never sends me the follow up text it says it will and I can't get through to a real tech. I just got off chat with Alfredo and he says he filed a support ticket and a tech will be out eventually but can't tell me when. I also can't let anyone into the house due to covid concerns. He insisted it was fixed though, so I'm not sure how seriously he's taking it. Again, he kept trying to hang up on me or get me off the line. He said comcast would notify me "when the tech confirmed the problem was in my house". So for sure it's my problem, from his perspective.

13. Event logs only show a few ipv6 negotiation errors (82 and 24 config not set) but I have a ipv6 address assigned on the WAN and there aren't very many of them, mostly around reboots. Nothing in the system or firewall logs of note.

14. traceroute and ping tests from the onboard diagnostics section look good.

15. I've read a ton of similar posts (here, reddit, tom's hardware, regular internet searches), mostly people getting 200-400 instead of 900, but some people sub 100. Nothing  I tried from those posts worked.

- Can low signal strength manifest as a steady connection that has no problems, no latency issues, no lost packets, but is just slow and steady ?

- Wouldn't signal strength issues lead to at least SOME errored codewords ? I do see one channel has about 5k after 12 hours, literally 0 on ALL the others.

- This really feels like I'm being limited to 33 mbits by something. It is SO STEADY across all my devices and Mac, PC, ipad, 2 iphones. Or maybe it's limited to 1 channel for some reason ?

- Why would my old modem work at faster than advertised speeds with no problems on the same cable but going through another router ? (I even tried the same coax cable to the wall).

- Weird that upspeed is what it should be. That indicates that I have the right bootfile, right ?

- Is it worth buying and trying my own modem here just to see ? (Looking at the netgear r7200 and I am willing to spend my way out of this problem, I need fast internet for work)

- Is it worth trying my own signal booster ?

- Any ideas for other things I can try ? I'm a cloud engineer, so I get hardware and software and some network config but I'm not really a network engineer.

- I'm guessing the answer is "get a tech to look at your lines" and possibly "use the old modem until then", but it's just so STEADY. And stable, more stable than my old connection seemed to be.

Sorry for any frustration that is coming across here. I really do appreciate how friendly comcast support has been in general and I know they're doing their best and the higher level techs are busy, especially right now. It just hurts to hear it's fixed over and over.

- Can they see signal strength from their end to the modem ? They say it's fine but... something is broken, right ? That or the bootfile seem like the most likely things ? Or maybe some modem config setting...

Thanks for any help here! I know this is a lot. Pasted some stuff from the Xfinity network tab below (sorry for the formatting!):

Index	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31	32	0
Lock Status	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	NotLocked	Not Locked
Frequency	423000000	429000000	435000000	441000000	453000000	459000000	465000000	471000000	477000000	483000000	489000000	495000000	501000000	507000000	513000000	519000000	525000000	531000000	537000000	543000000	549000000	555000000	561000000	567000000	573000000	579000000	585000000	591000000	597000000	603000000	609000000	615000000		0
SNR	33.486542	33.486542	33.956509	33.834164	33.834164	33.834164	33.834164	32.237156	31.201750	32.676208	33.834164	33.376591	32.584778	33.062504	33.486542	27.170025	30.366289	33.376591	33.599354	33.834164	33.376591	32.584778	28.983261	30.206408	33.062504	28.462973	31.615677	30.646576	26.942062	31.915308	33.834164	33.376591		NA
Power Level	-16.299999	-16.500000	-16.000000	-16.200001	-16.000000	-15.700001	-15.700001	-15.799999	-15.599998	-15.700001	-15.700001	-16.200001	-16.599998	-16.500000	-16.400002	-15.900002	-16.299999	-16.099998	-15.900002	-15.500000	-16.099998	-17.400002	-17.400002	-17.099998	-16.200001	-16.400002	-16.599998	-16.500000	-16.200001	-15.500000	-15.200001	-15.599998		NA
Modulation	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	UNSUPPORTED	UNSUPPORTED

Index	1	2	3	4
Lock Status	Locked	Locked	Locked	Locked
Frequency	18600000	25000000	31400000	37800000
Symbol Rate	5120 KSym/sec	5120 KSym/sec	5120 KSym/sec	5120 KSym/sec
Power Level	54.520599	54.520599	52.770599	52.270599
Modulation	64QAM	64QAM	64QAM	64QAM
Channel Type	US_TYPE_ATDMA	US_TYPE_ATDMA	US_TYPE_ATDMA	US_TYPE_ATDMA

Unerrored Codewords	9152	9152	9153	9153	9152	9153	9153	9152	9152	9153	9153	9152	9152	9153	9152	7502	9153	9152	9152	9126	9125	9125	9122	9125	9125	9034	9125	9125	4265	9125	9125	9125	0
Correctable Codewords	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	1651	0	0	0	0	0	0	4	0	0	92	0	0	4464	0	0	0	0
Uncorrectable Codewords	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	397	0	0	0	0

[CCAndrew]

If you have a signal booster amp and are getting in the negative teens, you’ve got problems. Test it before and at the amp to compare. Post the levels you see and the upstream levels. What kind of amp?

[CCAndrew]

If you have a signal booster amp and are getting in the negative teens, you’ve got problems. Test it before and at the amp to compare. Post the levels you see and the upstream levels. What kind of amp? SNR is out of spec for all channels too

[db54]

No idea, comcast installed it years ago. What's a good way to test it before and after ? Should I just unscrew it and plug in the modem ? Not very comfortable on the physical side of tech (real world physics hates me).

The booster, or that's what I assume it is, is before it comes into the box on the side of my house, I wasn't sure if that box is doing something or is just a bundle of cables inside. Kind of scared to pry it open, I've got serious squirrels in this neighborhood and if there's a crack they will exploit it.

[db54]

Also any thoughts on the specific problem I'm seeing ? Slow speeds but a great connection ? I'm just not sure how you get that with low signal strength and I don't want to read the DOCSIS 3.1 protocol... although I suppose I might get around to that.

[CCAndrew]

Right now you don’t have a great connection. Take your modem to the amp unhook the input, hook it up to your modem, take your levels. You need a comparison and have to start somewhere. Or have a tech out

[db54]

This thing is just an AC ADAPTOR (model AD35-1200200DU) and it seems to be ... plugged in to the wall with the cable coming out one side of it and connecting to the box, but no input cable that I can see. What is this thing ?

https://www.dropbox.com/s/twju7sybbzvr7rz/Photo%20Jul%2017%2C%201%2042%2046%20PM.jpg?dl=0

https://www.dropbox.com/s/v1zo1x72ffdsc4l/Photo%20Jul%2017%2C%201%2042%2040%20PM.jpg?dl=0

[db54]

Ahh, that is just providing power to the real amp in the squirrel house, ahem, cable box I mean.

[db54]

There are 3 splitters daisy chained in that box...

[CCAndrew]

Do you have cable boxes too? The way it’s set up, no surprise you’re in the negative teens

[db54]

No. We used to. Only one line.

[db54]

One sec getting pic

[db54]

https://www.dropbox.com/s/8q772l3yu80x599/Photo%20Jul%2017%2C%201%2052%2050%20PM.jpg?dl=0

[db54]

All I need is one line coming in and one out! They come in, go to small splitter, go to another splitter, then to the big thing which I assume is an amp of some sort, then out to various useless places and one that is the modem. What should this look like?

[CCAndrew]

In that case, find the line that feeds your modem, bypass the amp, hook it up to the line that was feeding the amp, bypass the splitters and go on from there.

[db54]

Thanks I will try that and now I have a tech appointment.

[Mattymmartin]

Did it get fixed after the tech visit?? Because they refuse to send out a tech for me as well! I'm having the exact issue except I'm in a town house apartment... I spent close to 12 hours on the phone with them myself on the day it started happening.. Got hung up on 3 times. Got cold transferred 3 times... Got lied to 10 times because I talked to probably 10 people and they all blew smoke up me.. I called so much I now automatically go to the escalation team apparently. They credited me 50 dollars for the month but I lost 170 dollars because I missed work because I was on the phone with them all day long. I literally get speeds that range from 25 to 35mbps. Upload is 35 to 41mbps and my ping is like a 10-12. I went through EVERYTHING the gentleman above me did and all they told me was "oh well" essentially.

[db54]

Tech visit is on Sunday so we’ll see then. We straightened out the splitter mess, now just the amp is inline (didn’t work without it) and are now seeing 2.6 instead of -16 and somewhat better signal to noise. Unfortunately I already switched back to the old modem so I’ll have to wait to re-hook up gigabit before I can tell. Also getting periodic slowdowns but not sure why because the signal looks great now (slow down to 2mb from the 280 I’m getting with the old non gigabit modem).

[db54]

Sounds like the exact same thing. They offered to upgrade me to a different modem, maybe try that? I also called direct and talked about the cable mess which is why they decided to send someone.

[Mattymmartin]

Well unfortunately I can't go fiddling with mine cause I'm in an apartment..

[db54]

Maybe start your own thread and ask ? Probably better than posting here, it's no longer on "front page". If I find a solution I'll post it here though and hopefully that'll help.

Update on my situation: Much better connection, switched back to the gigabit modem, but... still only geteting 32mb.

Index	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31	32	0
Lock Status	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	Locked	NotLocked	Not Locked
Frequency	423000000	429000000	435000000	441000000	453000000	459000000	465000000	471000000	477000000	483000000	489000000	495000000	501000000	507000000	513000000	519000000	525000000	531000000	537000000	543000000	549000000	555000000	561000000	567000000	573000000	579000000	585000000	591000000	597000000	603000000	609000000	615000000		0
SNR	38.983261	38.983261	38.605377	38.605377	38.983261	38.605377	38.605377	35.779911	37.355988	37.636276	38.605377	38.605377	38.605377	38.605377	38.605377	29.144131	30.646576	36.609653	38.605377	38.605377	38.605377	38.983261	33.062504	34.483570	37.355988	31.136440	34.925610	36.386890	31.136440	35.779911	38.605377	37.636276		NA
Power Level	1.500000	2.000000	2.500000	2.400002	2.099998	2.099998	2.200001	2.299999	2.700001	3.000000	3.099998	2.900002	2.500000	2.700001	2.599998	2.700001	2.299999	2.299999	2.900002	3.700001	3.400002	2.400002	2.099998	2.400002	2.799999	2.700001	2.500000	2.500000	2.799999	3.299999	3.500000	2.799999		NA
Modulation	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	QAM256	UNKNOWN	UNSUPPORTED

Index	1	2	3	4
Lock Status	Locked	Locked	Locked	Not Locked
Frequency	18600000	25000000	31400000	37800000
Symbol Rate	5120 KSym/sec	5120 KSym/sec	5120 KSym/sec	5120 KSym/sec
Power Level	49.520599	49.770599	48.770599	48.770599
Modulation	64QAM	64QAM	64QAM	64QAM
Channel Type	US_TYPE_ATDMA	US_TYPE_ATDMA	US_TYPE_ATDMA	US_TYPE_ATDMA

Unerrored Codewords	9394	9403	9402	9403	9403	9402	9402	9402	9401	9402	9402	9402	9402	9401	9402	9287	9401	9401	9401	9401	9402	9401	9401	9401	9401	9401	9401	9401	9400	9401	9401	9400	0
Correctable Codewords	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	114	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Uncorrectable Codewords	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0

[db54]

Got an update from the network guy and they can only look at the box outside the house due to covid. This really feels like an account setting issue at this point. Is there a way to get a higher level tech involved that isn't just going to walk us through reset a dozen times ? Or will their on site guy be able to answer questions about a modem he can't see ?

[db54 · Accepted solution]

Update from tech: Our signal was strong after the amplifier but without it it was "garbage". He also replaced the modem and things are working so this is resolved!

I'm getting 550mb from xfinity speed test but 900 from ookla. Strange that their speed test is more limited but what can you do. I wonder if a bunch of the "I'm getting 500 instead of 1gb" people are just using the xfinity speed test and not trying others ?

Takeaways:

- Apparently you can get a solid connection with a bad line just at a slower speed. The modems negotiate a rate or something.

- You can get 300mb with an old modem but a newer modem (or maybe just protocol) apparently needs a better signal or it won't go as fast.

- Strong signal strength means nothing; amps are not magical data fairies. Not sure why the SNR wasn't messed up and why there weren't more errors, but probably to do with part 1.

For the person with the same problem: I'd call and try to get a brand new modem. This one is white and has a vent on top. It's possible the fix was just replacing the modem, but I'm sure the signal strenght contributed on some level. If that doesn't fix it the it is unfortunately probably a line problem 😞