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trent

join:2012-02-24
Philadelphia, PA

[Signals] SB6121 new firmware messed up my upstream!

Click for full size
signals

new firmware
Last night a new firmware was pushed to my SB6121 and immediately things got screwed up. I lost upstream channel bonding and my upstream power level went from 47-49dBmV to 57dBmV, but I am still connected. Tried resetting to default and rebooting, but no change.

Signal levels were checked and balanced only a month ago because of low downstream power. I am only about a 100 feet or slightly more away from the tap installed in my building and have no splitter on the line coming into my modem.

A google search led me to numerous complaints on Comcast's forums about issues with the new firmware. Why are they still pushing it if there are reported issues! I own the modem, not leased, so I cannot go swap it for another model to avoid this firmware problem. What can I do now? Sit and wait for Comcast to fix things?

By the way, when the new firmware was being pushed and updated I was doing some work online, and thought it was a connectivity or modem crash issue because it was taking long for it to reboot or do anything (all lights were blinking for over 2 minutes). So I unplugged the power and replugged it, not knowing that a firmware update was in progress and wanting to get back online asap to continue my work. When the modem was back online with the above issues I checked the log and there was messages about a failed firmware update due to power loss but following that were messages about successful update on the second boot I suppose. I no longer have the log messages since I reset the modem. I don't suppose I screwed up things and caused my upstream issues with my impatience, since it is online now?


tshirt
Premium,MVM
join:2004-07-11
Snohomish, WA
kudos:4

Was your upstream on Channel 3 before?


trent

join:2012-02-24
Philadelphia, PA

I don't recall what my upstream channels were before. But I used to have 3 channels bonded on the upstream, and the channel numbers would change if I rebooted


trent

join:2012-02-24
Philadelphia, PA
reply to trent

Click for full size
Signals at 2nd outlet
I tried another outlet that's on a different run from the tap. Same results.

I also seem to have lost powerboost, in addition to some upload speed due to the loss of channel bonding. But the speed still seems OK for such high upstream power. Tested with DiffProbe and monitoring with a bandwidth meter software that you can see in the signals screenshot. Sustained speeds with no powerboost effects.

I am on Blast, and have had the newer double speeds since I installed at this new apartment at the beginning of July.

DiffProbe:
----------

DiffProbe release. January 2012. Build 1008.
Shaper Detection Module.

Connected to server 213.244.128.151.

Estimating capacity:
Upstream: 10741 Kbps.
Downstream: 125397 Kbps.

The measurement will take upto 2.5 minutes. Please wait.

Checking for traffic shapers:

Upstream: No shaper detected.
Median received rate: 10528 Kbps.

Downstream: No shaper detected.
Median received rate: 52453 Kbps.

For more information, visit: »www.cc.gatech.edu/~partha/diffprobe


Scree
In the pipe 5 by 5

join:2001-04-24
Mount Laurel, NJ
Reviews:
·Comcast
reply to trent

What I would try first is hit Reset All Defaults, then unplug the modem for a few minutes (don't just reboot the modem). Then let it do its thing when power back up and check the signal page again. If back to normal then, great, otherwise I would next call and have them check things on their end, maybe they can re-push the update or config file, e.g.


trent

join:2012-02-24
Philadelphia, PA

I already tried that. I reset to defaults before unplugging everything and moving the modem to the 2nd outlet, a process which took at least 10-15 minutes with the modem having nothing connected to it.

I will try this evening to call. I try to avoid comcast's phone support because of previous experience of spending an hour on the phone only to end up were I started!

Would they be able to help through the direct support forum?



mb

join:2000-07-23
Washington, NJ

Another possibility is that a system issue is occurring and as a conseqhence of it, the modem lost sync, rebooted and updated it's firmware. Possibly the firmware update is not related at all to the issue. Call for service.


trent

join:2012-02-24
Philadelphia, PA

You're right that's a possibility. It was around 3am when this happened it could be that work was being done and something might have effected the signal levels.

Is it at all possible that my unpowering the modem during its first attempt to update the firmware screwed something up? Even if it managed to update on its second attempt?



tshirt
Premium,MVM
join:2004-07-11
Snohomish, WA
kudos:4
Reviews:
·Comcast

Maybe, but it should recover after a "Reset to defaults" IF left to do it.
I really doubt the firmware update changed the power level, but the powerlevel could mess up the update, and the way the modem calculates the correct power level MIGHT have bee adjusted, but I didn't see that happen here.


hclarkjr

join:2002-08-09
Hostetter, PA
reply to trent

i have the same modem and have had that firmware since i bought it 4-5 months ago. the build date is the same on mine as the one you have posted


trent

join:2012-02-24
Philadelphia, PA
reply to trent

Click for full size
US bonding is back!
Click for full size
error log
I think mb See Profile was right about the overlap of firmware update and signal problems. The firmware might not be the source of my problems after all, maybe!

I returned home tonight, and found upstream power to have dropped to 54dBmV, but no channel bonding on upstream.
But after a reset and restart upstream channel bonding returned (3 channels like before) and upstream power is now 51dBmV on all channels. This is just within the recommended levels according to the FAQ, and higher than what I used to have (47-49dBmV).

I haven't had the chance to call Comcast yet. Should I still call regarding my upstream power? or is it OK now?

What does the warning message mean? I don't recall seeing a "MIMO Event" related message before with the old firmware.


elkido122

join:2011-02-23
Folsom, CA

i dont know what the mimo means. also the tlv-11 who knows


andyross
Premium,MVM
join:2003-05-04
Schaumburg, IL
reply to trent

For 3-stream bonding, the max for 32 and 64QAM is 51dB. For 16QAM, it's 52dB.

So, you are still at the limit since all 3 of your channels support 64QAM.



Scree
In the pipe 5 by 5

join:2001-04-24
Mount Laurel, NJ
Reviews:
·Comcast
reply to trent

said by trent:

I haven't had the chance to call Comcast yet. Should I still call regarding my upstream power? or is it OK now?

If everything is working for now, I would wait to call (I know how you feel trying to deal with them sometimes -lol). I've had times where the upstream power mysteriously jumped lile +5 for a few days, then went down to a better level than I had before the jump up. So it could be a coincidence since your firmware update that they just happen to be replacing something down the line that will clear up the level soon.

As for the error log, it's just normal operation, apparently. I see the same entries often enough too.


Lute

@twtelecom.net
reply to trent

Hi Trent,
I too have been having issues since purchasing the SB6121 and called comcast about the issue. They sent out a tech and he thought my incident was due to a faulty network adapter (onboard nVidia 10/100/1000).

He tried the modem with his laptop and the network was stable and was able to connect to the internet. I also have a netbook but the adapter is 10/100 and it has held a stable internet connection since his departure until the evening when i powered it down (have not been home since this morning so unsure about during the day today).

It might not be your issue but it something to look into 1) try a different computer/laptop/netbook to see if you get a stable signal 2) look at your network adapter and try a 10/100 adapter if you have one to see if it is related to 1000 speed adapters.

I am not a expert in any way/shape/or form but these are things that I have thought might be the problem.



pooh40cal

@comcast.net
reply to tshirt

im having the same issue