Basic Internet Connectivity And Modem Help

[spitfire9200]

    I have been calling customer service countless times and even have a tech checking my line. I know for a fact that my line is being throttled or speed being limited. I download large files often via dedicated servers for work and know the speed issue isn't on their end. At my last apartment, I was getting 4 to 5 megabytes per second on these servers (And I had a lesser tier plan!!). Now I am lucky to get 3 megabytes for about 2 seconds, and then it ALWAYS drops to 1 - 1.75 megabytes per second. 

 I have tried a different coax port, a different router, connecting directly to the modem, everything. Please please stop throttling my connection and direct me on how to get my problem resolved. This was never an issue at my old apartment.

My previous connection with you guys that worked great was a 15mb connection, now I have the BLAST service, and its almost 1/3 of the speed. Please help!

I have a moto SB6121 brand new, and a Linksys E3200 Dual-Band N router with CAT6 ethernet to both. 

Also, It seems my upload and my download are both being throttled/shaped: 

DiffProbe release. January 2012. Build 1008.

Shaper Detection Module.

Connected to server 64.9.225.179.

Estimating capacity:

Upstream: 4379 Kbps.

Downstream: 22217 Kbps.

The measurement will take upto 2.5 minutes. Please wait.

Checking for traffic shapers:

Upstream: Burst size: 4699-4781 KB;

Shaping rate: 2128 Kbps.

Downstream: Burst size: 8108-8491 KB;

Shaping rate: 15213 Kbps.

This is really killing my connection and would really like it to stop! It was never a problem before what the heck happened...

Modem info: (just reset it)

Downstream Bonding Channel Value Channel ID 4  5  7  8  Frequency 631750000 Hz  637750000 Hz  649750000 Hz  655750000 Hz  Signal to Noise Ratio 34 dB  35 dB  35 dB  35 dB  Downstream Modulation QAM256  QAM256  QAM256  QAM256  Power Level The Downstream Power Level reading is a snapshot taken at the time this page was requested. Please Reload/Refresh this Page for a new reading 0 dBmV   1 dBmV   0 dBmV   0 dBmV  Upstream Bonding Channel Value Channel ID 1  Frequency 36800000 Hz  Ranging Service ID 3932  Symbol Rate 5.120 Msym/sec  Power Level 50 dBmV  Upstream Modulation [3] QPSK
[3] 64QAM
  Ranging Status Success Signal Stats (Codewords) Bonding Channel Value Channel ID 4  5  7  8  Total Unerrored Codewords 99361076  99389010  99407332  99397916  Total Correctable Codewords 180720  152896  134575  143817  Total Uncorrectable Codewords 642  720  861  567 Frequency Plan: North American Standard/HRC/IRC Upstream Channel ID: 1 Favorite Frequency (Hz) 631750000 MDD IP Mode Override (MIMO) IPv4 Only Modem's IP Mode IPv4 OnlyPlease help me this is ridiculous!!

[Jim721]

Your upstream power is at 50 dbmv that is borderline to high this may be your issue.

[spitfire9200]

hmm.. I'm advanced on most networking, but that stuff i'm a novice to. Could you elaborate? 

[rson123]

Experiencing the same issue on "Blast" right now and anxious to hear more about how upstream power impacts my Internet speed as well... please elaborate Jim721?

[Jim721]

Your Upstream power levels can have a big effect on your over all connection if they go out of spec. 50 dbmv is right at the high point, low to mid 40's is what you want to see.   

[spitfire9200]

ok, could a tech that comes to my apartment be able to address this issue?

What about what shaper probe detected? Seems like pretty heavy throttling... I've never experienced it before sigh...

[Jim721]

If your sure all your coax lines are good then yes you may benefit from a tech visit. 50 dbvm is starting to get hot. Jim !!

[shuck1]

Sounds like noise,    Comcast will not throttle your data . and since you live in an apartment who knows what kind of cable is being ran through it  to your rental

what  speed tier are you paying for 

you could have RG59 line running to the modem also it could be a sucked out connector or possibly be water in the line. untll they eliminate all these variables you will never get the problem fixed. depending where you are at the apartment I would have them run a line from the modem to the tap on the side of the building to eliminate the wiring.

-CS

[i-am-nerdburg]

Your speeds are fine according to ShaperProbe. At the time you ran the test your sustained speeds were about 15/2 and 23/7 with Powerboost. You might want utilize a download manager to open multiple connections to a server, this will allow you to take advantage of your bandwidth.

Blast speeds vary by area, you'll probably want to call in and be sure your modem is correctly provisioned.

You might want to run a tracert and grab another set of levels when you feel you speed is at its worse for comparison.

[spitfire9200]

Thanks for all the responses guys!

Jim721 - thanks for the input, tech is coming out tomorrow. 

shuck1 - thanks for your input as well.. .Comcast doesn't throttle/shape? I've heard so many people talk about it. I was also under the impression it's being throttled due to the shaperprobe results... I am very new to all this stuff though so I am learning from all your input  

I pay for the 30 mb down BLAST service. I had the Preformance before (20mb tier) at my old apartment, with the older SB6120 modem and it was triple the speed, but I believe my line was fed directly from the outside as you reccommend shuck1. 

 I'll see what happens tomorrow and then report back!

[spitfire9200]

i-am-nerdburg - Those speeds are acceptable for the 30mb blast service? I am using a dedicated newsgroup server to test my connection speed with up to 50 connections at once, so the download manager isn't the issue. It still doesn't explain why I was getting up to 5mb down at my old place with Comcast, an older modem, and the lower tier, but get 1.7 megs MAX now, in a new place at the higher tier. 

That just makes absolutely no sense. 

It's either throttling/shaping or the line issues as people have said. I don't use the speedtests, as they are worthless, I'm using something I used in the exact same manner at my old apartment.. .trying to eliminate all variables. 

Also, I've called multiple times and they have re-provisioned my modem and made sure the MAC was tied to my account etc etc

[i-am-nerdburg]

First, you have to understand how Comcast advertises their speed tiers. Blast is 16/2 or 20/4 or 25/4 depending on your local system. These are sustained speeds not including PowerBoost. All of them are advertised as "speeds up to 30 Mbps" which is what you'll see briefly due to PowerBoost. So if you are in an area where Blast is 16/2, your speeds are about right.

ShaperProbe shows your sustained speed and your speed with PowerBoost. In this case, shaping is a good thing --you get a short burst of speed to address the bursty nature of the internet.

Your modem may not be configured correctly, which is why I suggested you ask Comcast to check the provisioning.

Comcast does not throttle speeds except under specific conditions as part as their congestion management scheme. If you are a heavy user on a busy node, your speeds could be reduced temporarily. What you are describing does not sound like congestiona management tho.

[spitfire9200]

nerdburg -  ok cool.. taking this info in.. What should I tell them specifically? I have told them countless time to check my provisioning etc on the modem, but their customer service is completely out of it.

I even start to lose connection quality while streaming a hockey game last night on a great server.. it really sucks.

advice? 

[EG]

---

shuck1 wrote:

Comcast will not throttle they just monitor your data BPI+.

---

Please elaborate on what "BPI+" has to do with "data monitoring" or anything here.

[i-am-nerdburg]

Shuck1 might be on to something. Your return power level is high and your SNR is just OK. Plus apartment buildings are notorious for noise issues. There is a fair chance that you have some intermittent noise issues. You might want to call Comcast and ask for your upstream SNR (uSNR).

You should contact Steve Teow (AKA ComcastSteve) via twitter, private message via these forums or by email. He can check your account and make sure your modem is set up correctly.

[spitfire9200]

I will contact ComcastSteve... yes what is BPI+?

[EG]

---

spitfire9200 wrote:

yes what is BPI+?

---

Sorry for the technical jargon.

Quote;

"Baseline Privacy Plus (BPI+) provides cable modem users with data privacy across the cable network.
It does this by encrypting traffic flows between CM and CMTS.
 
In addition, BPI+ provides cable operators with strong protection from theft of service.
 
The protected DOCSIS MAC data communications services fall into three categories:
• best-effort, high-speed, IP data services
• QoS (e.g., constant bit rate) data services
• IP multicast group services
 
Under BPI+, the CMTS protects against unauthorized access to these data transport services by enforcing encryption of the associated traffic flows across the cable network.
 
BPI+ employs an authenticated client/server key management protocol in which the CMTS (the server), controls distribution of keying material to client CMs (Cable Modems).
 
The original BPI specification had “weak” service protection because the underlying key management
protocol did not authenticate CMs. BPI+ strengthens this service protection by adding digital certificate
based CM authentication to its key management protocol.
 

[spitfire9200]

ok thanks! great info.

[spitfire9200]

i'll report back and keep it updated.. .i want this fixed!

[spitfire9200]

UPDATE: 

  Tech came out and said there were huge amounts of BER (?) errors, fluctuations,  as well as failure rates within the line and even from the main line in the cable room. He is referring it over to Comcast maintenance to fix the problem.. I asked him if there is any way I could follow up on the request or be notified on progress/fix, but he said once it was out of his hands he doesn't know.... How will I be able to know when/if the problem will be handled?

Could I also seek some kind of credit due to my service tier not being what I pay for due to line errors with a mystery date of when it will be fixed?

[shuck1]

I would 

-CS

[EG]

B.E.R. = Bit Error Rate. The SNR (Signal to Noise Ratio) as read by a modem's measuring mechanism is actually an abstraction of the BER. If the bit errors are high the SNR is low and vice versa. Noise ingress is the typical cause of a high BER.

[shuck1]

Just a little more definitions

BER is an acronym bit error ratio, sometimes referred to as bit error rate. The ratio of bit errors is the number of errors received compared to the total number of bits received in a specified time period.

CNR is an acronym for carrier to noise ratio. On a cable plant, CNR is measured in dBmV. The measurement is the distance between a modulated RF carrier and the inherent noise floor. As of June 30th 1995, CATV plants with a subscriber base larger than 1000 must meet a minimum CNR of 43 dBmV.

MER is an acronym for modulation error ratio. MER is the digital equivalent to Signal-to-Noise which is the baseband measurement equivalent to Carrier-to-noise. MER measures the ratio of error power to average power on an ideal QAM signal. MER measures the difference in quality between the transmitted modulation of a digital signal the received modulation. This measurement can be made with a digital signal analyzer and can be graphically represented if the analyzer supports constellation display.

-CS

[EG]

Ain't Google great !!! 

[shuck1]

Sorry this didn't come from google

-CS

[Jim721]

Must have been Bing then. LOL 

[shuck1]

You Gotta love the comedians

-CS

[spitfire9200]

lol, ok thanks guys... So anyone know of a way to follow up w/ the maintenance to make sure it is in fact fixed? He said the BER was huge even in the cable room.

So I guess it wasn't throttling, hardware/line error

[shuck1]

I would try to call comcast and see if a ticket was made usually at least  with me Maint was usually out the same day. just stay on top of it  Or it may still be an issue

-CS

[spitfire9200]

will do.. keeping everyone posted. 

  Definetely need the main line fixed, i'm experiencing major upsets during peak hours. The Tech said with this type and amount of BER errors, multiple users would just exacerbate the issue

[spitfire9200]

Now my freaking TV stopped working in my room, s0a00 error... We know it's the wiring. ANOTHER tech is coming out. This is getting ridiculous..

How can I get this resolved? Any Comcast higher UPS reading this?? I just want my full internet speed and TVs to work gosh...

I need to know how to get maintenance to correct this and how to follow up that it ACTUALLY IS being corrected. I have a feeling tech will come out tomorrow and fix my TV and destroy my internet connection again. Wth I can't have both running optimally and as advertised?

/rant

Help

[i-am-nerdburg]

To get help, you can contact Comcast Corporate Customer Service (we_can_help@cable.comcast.com) Send a link to this thread and your account details. You can also ask for help in the Broadband Reports Comcast Direct Forum or via Twitter.

[spitfire9200]

Simply waiting on the maintenance team now.

[8307c4]

I am very sorry you feel your connection is being throttled but you, as most users, are still very uneducated as your initial post concerning speeds of 4-5 MB / Sec puts to evidence... It wasn't long ago Comcast didn't have a pay-per-tier (or as I call it pay-to-play) system, and not long before that I used to get speeds of 300 MB per second, you did read that correct... One gig used to take 2-3 seconds on a good day.

Unfortunately, it is users like us who have prompted these measures, when you speak of raiding arrays and dedicated servers and downloading large files and backing up hard drives via the Internet you are also what many consider to be, abusing the system, and it is because of people like you (and I) that they are doing this except...

Their little tier plan does give away a slight indication that another factor (such as GREED) could be at play.