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Gigabit Internet speed issue

Regular Contributor

Gigabit Internet speed issue

I was up this morning at 4am playing World of Warcraft when my modem rebooted.  I checked the cable TV since usually when the internet goes out, I can no longer load the Guide, but that was working, so it seemed to be some kind of planned maintanence.

 

When the modem came back from reset, though, my upload and dowload speeds were reduced almost 30%!

 

My speed before: http://www.speedtest.net/result/7299118165

 

My speed after: http://www.speedtest.net/result/7313676366

 

These speeds were consistent, the former over a period of a week or so of testing, and the latter has been consistent through the day, even with a reboot of the modem and PC.  No latency issues at all.. Just wondering if this is normal and it'll fluctuate week to week or if something was misconfigured by accident.

 


Accepted Solutions
Official Employee

Re: Gigabit Internet speed issue

Hi Uriel_Dagda, 

 

I can take a deeper look into this for you. Please send me a private message by clicking on my name, "ComcastChe" then click private message me. In the body of this message please verify your first and last name, street address including city state and zip code, and the account number or phone number associated with your services.


All Replies
Problem Solver

Re: Gigabit Internet speed issue

700 download isn't that bad, given your ping is still reallly good. I've seen my connections drop from 942 to 800 or even 600 throughout a period of a day or three. Unless you're seeing your connectivity drastically affected I wouldn't worry too much about it at all. 


"Sometimes the best way to learn something is by doing it wrong and looking at what you did." - Neil Gaiman
Problem Solver

Re: Gigabit Internet speed issue

Yeah but now the OP upload is below advertised.

Try posting your signal stats. You can see them at either http://10.0.0.1 or http://192.168.100.1
Regular Contributor

Re: Gigabit Internet speed issue

Downstream
Channel Bonding Value
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
Lock Status
Locked
NotLocked
NotLocked
NotLocked
NotLocked
NotLocked
NotLocked
NotLocked
NotLocked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Frequency
507000000
               
513000000
519000000
525000000
531000000
537000000
543000000
549000000
555000000
561000000
567000000
573000000
579000000
585000000
591000000
597000000
603000000
SNR
40.366287
               
40.366287
40.366287
40.946209
40.366287
40.366287
38.983261
40.366287
40.946209
38.983261
38.983261
38.983261
38.983261
38.983261
38.983261
38.983261
40.366287
Power Level
3.799999
               
3.500000
2.900002
2.799999
2.900002
3.099998
2.900002
2.500000
2.799999
2.500000
2.400002
2.099998
2.299999
2.000000
1.500000
1.799999
2.000000
Modulation
QAM256
UNSUPPORTED
UNSUPPORTED
UNSUPPORTED
UNSUPPORTED
UNSUPPORTED
UNSUPPORTED
UNSUPPORTED
UNSUPPORTED
QAM256
QAM256
QAM256
QAM256
QAM256
QAM256
QAM256
QAM256
QAM256
QAM256
QAM256
QAM256
QAM256
QAM256
QAM256
QAM256

 

Upstream
Channel Bonding Value
Index
1
2
3
4
Lock Status
ACTIVE
ACTIVE
ACTIVE
ACTIVE
Frequency
17300000
23700000
30100000
36500000
Symbol Rate
5120 KSym/sec
5120 KSym/sec
5120 KSym/sec
5120 KSym/sec
Power Level
48.770599
47.270599
47.770599
48.770599
Modulation
64QAM
64QAM
64QAM
64QAM
Channel Type
US_TYPE_STDMA
US_TYPE_STDMA
US_TYPE_STDMA
US_TYPE_STDMA
Problem Solver

Re: Gigabit Internet speed issue

Here’s a possibility. There is a slight chance that your Upstream figures could be fluctuating to out of spec levels. Try calling Comcast or be able to obtain the the uSNR, ICFR and Upstream Receive Power.
Expert

Re: Gigabit Internet speed issue

.@ 

 

Do you see a downstream channel labeled as being an "OFDM / PLC" or "Other ? With only 17 multiple bonded downstream channels you are not going to get gig speed.

Regular Contributor

Re: Gigabit Internet speed issue

What I don't understand is my old modem from Blast! was still listed as being under my account until the day my modem rebooted.. It's like they made some change and it knocked my speed down.  So I'm guessing that they just re-provisioned my modem and didn't get the settings right.. It was getting 920+mbps consistently for download up until that happened.

Expert

Re: Gigabit Internet speed issue

What is the answer to the question that I asked ? What is the make and model number of it ? Have you tried power-cycling it again to see if it will re-range for more channels / the OFDM channel ? Depending on the make and model of cable modem, or if it is a gateway device, it may be able to be reset back to factory defaults. This may also help to pull those channels if they are actually present on the CMTS / system.

Regular Contributor

Re: Gigabit Internet speed issue

Power cycling did nothing..

Comcast XB6 modem

Cable Modem

HW Version: 11
Vendor: ARRIS Group, Inc.
BOOT Version: 0.1.9.430478
Core Version: 0.0.0.0
Model: TG3482G
Product Type: XB6
Flash Part: 469 MB
Download Version: 7.1.0.53
Expert

Re: Gigabit Internet speed issue

You could try the hard reset back to factory defaults by pressing and holding in the recessed reset button on the rear for 30 seconds. Be advised that you will lose any customized settings if you do, and they will need to be re-configured. 

 

There's no guarantee that this will do the trick if they are not present. Good luck !

Regular Contributor

Re: Gigabit Internet speed issue

Well if they aren't present, that means that when Comcast reset the modem they.. removed them.. since I got 920+mbps before. lol

Regular Contributor

Re: Gigabit Internet speed issue

Well I just did the full factory reset and it's the same.. Apparently they just updated it that way.. So I'm artificially capped at 700/30 instead of 940/42.  Oddly enough that subtracts from my speed exactly what I was getting with Blast before upgrading.

 

Oh well. As long as I'm not having latency issues, it should be plenty fast.. A little disappointed losing upload speed, though, since I tend to upload 2-3 hour 1080p files to YouTube several times a month, but I'll most likely not notice the download difference.

Expert

Re: Gigabit Internet speed issue

@Uriel_Dagda

I've asked an employee to check the CMTS for real-time and historical RF signal reports from your modem. They can also check your local node/plant for any degradation or error reports. You can expect a reply in this thread. 



"Keepin' it clean since '09"
I am not a Comcast employee, just a moderator.
Regular Contributor

Re: Gigabit Internet speed issue

Ok thanks nerdburg!  I'm not geeky enough to really understand all of these numbers I posted or if it's normal or not, when I posted, I just wanted to make sure it was normal behavior, since I do have the Arris modem model that seems to be notorious for issues, but none of this seemed to be related to that (no bad latency or constant disconnects in games), but I just wanted to be sure it wasn't some other issue cropping up, since the modem does get quite hot compared to any other I've used.

I'm hoping it's just a configuration/provisioning issue from a pushed update.

Expert

Re: Gigabit Internet speed issue

You still haven't answered that question about whether or not you see an OFDM downstream channel ?

FWIW, they may have been taken down temporarily for technical difficulties / maintenance / repairs ? There may be something going on on your segment / plant / node because your upload speed is also now slower.
Regular Contributor

Re: Gigabit Internet speed issue

I don't know what an OFDM downstream is, and I didn't see anything labeled that anywhere.  I'm guessing that's one of the things missing now.  It seems like they sent a configuration change to the modem that turned off 8 channels.  Like I said, they still had my old modem they swapped out from when I had Blast!, and it seemed at the same time this XB6 modem was rebooted, that modem was removed from my account.

 

That's the best I can figure, since I'd think if there was some kind of connection issue going on, it wouldn't just simply still work fine, just slower.  If nothing helps though here over the weekend and it doesn't correct itself in case it's related to some issue in the area, I'll just have to call Comcast on Monday and see what's up.

I'm just hoping it's not an Arris TG3482G issue.  I basically only realized all of this because I had read about all of the issues with the Arris XB6 modems, so I was watching for any irregular behavior.

Expert

Re: Gigabit Internet speed issue

FWIW, losing the OFDM and / or the balance of the downstream channels would not affect your upload speed.

Official Employee

Re: Gigabit Internet speed issue

Hi Uriel_Dagda, 

 

I can take a deeper look into this for you. Please send me a private message by clicking on my name, "ComcastChe" then click private message me. In the body of this message please verify your first and last name, street address including city state and zip code, and the account number or phone number associated with your services.

Problem Solver

Re: Gigabit Internet speed issue


@Uriel_Dagda wrote:

I don't know what an OFDM downstream is, and I didn't see anything labeled that anywhere. 


It's the DOCSIS 3.1 channel (i.e Gigabit),  and don't be alarmed - you wouldn't see it on the TG3482G as a separate channel. 


"Sometimes the best way to learn something is by doing it wrong and looking at what you did." - Neil Gaiman
Regular Contributor

Re: Gigabit Internet speed issue

The tech couldn't really pin down what was causing it, but a complete rewire seemed to have fixed it. Probably a dodgy or loose cable.  And apparently everything about the channel bonding that's displaying on my end is some kind of software glitch, because on Comcast's end the modem reports all channels up and running and in spec.

 

I live in an apartment building, so the wiring can be a nightmare, and sometimes something can get bumped and loosened when a tech is servicing other apartments.

Official Employee

Re: Gigabit Internet speed issue

I'm happy to hear the tech was able to help get this taken care of for you. You are correct, when it comes to apartment buildings and the wiring, things can get pretty ugly. Please don't hesitate to reach out if you need us in the future.