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TwiztedZero
Nine Zero Burp Nine Six
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Toronto, ON
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[Cable] Modem is not part of the Continuum. Intermittant SB6120

Intermittant signal drops ongoing SB6120 - Dupont.

So yeah, I allready had a tech out 2 weeks back who stuck a -3dB RF attenuator onto the back of my modem. It appeared to help in the short term. Long term not so much. And yes I'm considering another direct forum post regarding this. So be looking for that again soon. :(

Signals fluctuate a lot during the daytimes, tonns of T4 reboots every day all day long. Keeping a constant IRC connection beyond five or ten mins is like unpossible. Streaming unpossible. So anything that requires a constant uptime is a no go right now with intermittant disconnecting either regularly or randomly. Its pretty disheartening when you're in the middle of a convo or a show and you get dropped. :(

Its not the very best time to be considering laying out cash for a new modem eh, I mean with the holidays and all, I'm looking at Feb earliest to do that, if neccessary. Just SOL am I? Besides from what I've seen here on DSLr, a second modem doesn't always help make the problem go away. So I'm cautious about just throwing more money at the problem. Insert facepalm & headshake here.

quote:
Presently considering having another tech visit. What are the chances he could have me moved to another spigot on the tap and maybe replace the RF Trap filter thingy too(why do they even need this contraption anyways?), and inspect the line from the tap all the way outside the building to where ever it connects to the pedestal or node eh? Would be nice if someone could convince them to do that first. *Throws up arms*
I'm beginning to become unspeakably agitated by these constant T4 reboots since Sept. 21st onwards. And yes I've been thru the Constant Modem Reboots Thread so I'm wondering how many others on the Dupont POI with SB6120's are also still experiencing this annoyance? Did your problem ever get resolved?

I guess all I can do now is write up another "Form" with the modem logs and signals and all in the direct forum with three new potential dates, and request a second tech visit. Knowing the tech's will blame (a) my modem or (b)TSI's "servers" (the last guy did even spelling it as 'savers'), and I'll be dam'd if its the CMTS signal on the line card at the Dupont POI itself thats set too high causing flapping. I'm not too filled with confidence at this point on another tech visit, but what choice do I have eh?

:( So, thats where I am again *sigh*.

--
You see there is only one constant. One universal. It is the only real truth. Causality. Action, reaction. Cause and effect.
Twitter:Merv Chat:irc.teksavvy.ca


Old Martin
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join:2006-02-23
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1 edit

Re: [Cable] Modem is not part of the Continuum. Intermittant SB6

In an attempt to possibly help our good ol' pal TwiztedZero See Profile. Would anyone be willing to help him test his modem. Seeing we've sent a tech as he's stated, possibly finding out if he's modem is causing issues would be the best course of action.

So, anyone willing to reach out & lend a hand?

Thanks,
Martin
--
TSI Martin (Escalations / Social Media) - TekSavvy Solutions Inc.
Authorized TSI employee ( »»TekSavvy FAQ »Official support in the forum )
Follow me on Twitter : @TSIMartin


sbrook
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reply to TwiztedZero
OK, It's hard to tell exactly what's going on here.

There are apparently more detailed logs available through a telnet interface ... maybe through Haxorware if that doesn't violate your modem's firmware.

From what I am reading, I think it goes like this ...

After an original boot up, when the modem does its initial ranging, it can do what is called maintenance ranging. Ranging is the ability of the modem to adjust its power output (upstream) to compensate for changing line conditions.

The modem will send the modem a RNG-REQ packet saying it wants to do maintenance ranging. The CMTS replies with an RNG-RSP packet saying got it, and then proceeds and follows that with a packet called a RNG-REQ Grant Map which tells the modem to increase or decrease power or "we're good".

A T4 timeout occurs when a cable modem fails to receive the RNG-REQ Grant Map from the CMTS within 35 sec. The modem may receive the Abort response in the meantime which means that the CMTS can't get a good signal from the modem.

So, there are many things that can cause this problem.

If lots of customers on the same CMTS are getting it, the usual reason is an overloaded CMTS.

If a single customer is getting it, it's more likely to be a line condition (temporary) such as a noise burst caused by a fault on the plant. It would be interesting to see if there is a TV problem around the same time.

Basically when this happens, the modem assumes the line/CMTS has gone crap and the only way to get online again is a reboot.


TwiztedZero
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reply to Old Martin
said by Old Martin:

In an attempt to possibly help our good ol' pal TwiztedZero See Profile. Would anyone be willing to help him test his modem. Seeing we've sent 2 techs as he's stated, possibly finding out if he's modem is causing issues would be the best course of action.
So, anyone willing to reach out & lend a hand?
Thanks,
Martin

Thats just 1 tech so far, just wanted to make that clear. I'm getting ready to do my 2nd request in direct forum soon for the second tech visit.

But yes meanwhiles, looking for other solutions. And any other info like the other post sbrook put forwards. As well as any info on similiar conditions from others on the POI that might indicate CMTS overloads and so on. and how might we go about fixing that if its the case of the line or the node.
--
You see there is only one constant. One universal. It is the only real truth. Causality. Action, reaction. Cause and effect.
Twitter:Merv Chat:irc.teksavvy.ca

jibby

join:2008-03-31
Reviews:
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reply to TwiztedZero
I'm not sure how i'd help Mero test his modem, but if i can i definitely will. I guess he could bring his modem over and i could use it for a little bit to see if it drops @ my place - i have a 6120 on Dupont and no probs over the last few months so it might be a good test spot.

And i'd like to help but i can't stare at his modem stats for x hours to see if it drops, so he'd probably have to leave it here for a day or two, at which point he's not gonna have an internet connection @ home... i dunno


TwiztedZero
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Toronto, ON
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reply to TwiztedZero
But OMGz, must be a quadzillion reboots by now... :(


Also noting, some of the CMTS-MAC's are comming up all zeros on the ones marked 6-notice
I mean whoa, holey moley ! This will go on for several hours, then I guess after 2am or so then it'll lock onto channels and hold steady with the odd disco/reboot here n there through the night.
Whatever's affecting it is largely happening through the daytime hours; and I just betcha thats cause of more people using the webs through those hours.

Whatever else I can do online in between reboots is in bursts during most of the day.

--
You see there is only one constant. One universal. It is the only real truth. Causality. Action, reaction. Cause and effect.
Twitter:Merv Chat:irc.teksavvy.ca


Waimea

join:2010-06-30
Toronto, ON

4 edits
reply to TwiztedZero
Hey man,

I'm on the same POI with the same modem.

EDIT: here's the fix that solved it for me:
»Re: [Cable] Teksavvy Cable Constant Modem Restart [SB6120]

EDIT 2: to further troubleshoot, try to borrow a docsis2 modem and see if the connection is stable for a while. I'm sure it's upstream that causes this problem because the aborted status was always on one or two of the channels at most.

To add to what sbrook said, it's the modem losing its mind trying to talk to the CMTS and this comes at random intervals. you have to cleanup every part between you and the main line coming from rogers.

My upstream was borderline, hovering around 53 to 55 dBmv but dropped to 48 immediately after the cleanup as you can see in my post. it has since dropped further to its current 43 /41.you'll notice that your downstream may rise when the problem is solved. mine was at 0 before and now sits at 6.

at first, I too used a splitter and it helped a bit in the short term. but the problem came back later and with a vengeance. curiously, the upstream bonding was turned off for a couple of weeks and the problem disappeared during that time.

1st do a search on dslr and try to find the excel file that logs the SB6120 stats automatically. it helped me get an idea about the frequency of the issue. it seems that your signal fluctuates a lot and this tool will provide a better picture.

two, don't expect the first few techs to know anything about it. the first two completely ignored the logs and just checked the signal on the spot, said it was good at the time and ran off quick.

it took three tries before an experienced tech told me that he replaced the following at the tap:connector, spigot, jumper & trap W. Do note that applies to apartments btw.

I also had the cable coming from the riser into my unit replaced and found that it had a few nicks from the staple guns they use. that may interfere with the signal too.

good luck man, It has taken me a multiple months to get it sorted and I know how annoying it can be.

if you have any questions don't hesitate to ask.

PS: I'm on upstream 64Qam now and you're not. strange!
--
Proud Teksavvy customer since 2007


TwiztedZero
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1 edit
said by Waimea:
1st do a search on dslr and try to find the excel file that logs the SB6120 stats automatically. it helped me get an idea about the frequency of the issue. it seems that your signal fluctuates a lot and this tool will provide a better picture.
Allready did that heh, Plus my modem is in my eyeline so I pretty much notice it go *poof* then watch the "xmas light show" as it renegotiates the channel bonding etc.

said by Waimea:
two, don't expect the first few techs to know anything about it. the first two completely ignored the logs and just checked the signal on the spot, said it was good at the time and ran off quick.

And this is the proccess that I want to short circut, and get at directly from the get-go; how exactly am I going to draw the particular tech I need to have on this visit that's going to take the time to actually do the real work of cleaning up the line.

said by Waimea:
it took three tries before an experienced tech told me that he replaced the following at the tap:connector, spigot, jumper & trap W. Do note that applies to apartments btw.
And this is exactly whats got to happen when that particular experienced tech comes in.

said by Waimea:
I also had the cable coming from the riser into my unit replaced and found that it had a few nicks from the staple guns they use. that may interfere with the signal too.
My cable comes in through the inside of the wall to a rogers wall jack, this is going to be a PITA. Now the line to the Tap itself (kind of looks like a distributor box) is just down the hall way maybe 20 feet from my apartment proper; up in the ceiling under an unsecured pannel. The other side of the tap I'm sure runs from the tap to where ever it meets the wall then passes through the brick/concrete outer wall material then is in freefall down the outside of the building then snakes its way along the side out of sight to some other part of the building that I can't actually follow from here; that entire run of cable is exposed to the elements (and I just know this is likely where the problem is lurking) [I could prolly take pictures, but those wouldn't help much] The building itself isn't a biggun, only 3 floors eh, but theres stores & a bar and all that down there too.

said by Waimea:
good luck man, It has taken me a multiple months to get it sorted and I know how annoying it can be.
Yeah I'm glad you eventually got yours fixed up, I can only hope mine doesn't take as long.

said by Waimea:
PS: I'm on upstream 64Qam now and you're not. strange!
I'm not too worried about 64QAM, that'll come when they fix the node I'm on eventually, theres got to be hundreds of nodes all thru a single POI so this, I don't expect will happen overnight.

Yep, was watching your thread and any others of similiar nature like a hawk. I've learned a lot watching DSLr/TSI boards, enough I'd hazard to guess I know more about CMTS's, modem's and signals allready than your average bandaid-level Rogers tech does. Its painfully apparent after the first guy I had here a coupple weeks ago.

The crux of the problem in getting a proper tech is "Oh, but your ISP isn't Rogers, so its either your modem, or your ISP's servers. so we really can't do anything; you'll have to contact your ISP again." You know that ole run around not our problem line. Yeah, thats obstacle 1, obstacle 2 is getting ahold of an actual qualified line tech with enough patience and time to actually go at it and repair/replace all the neccessary links along the line itself.
--
You see there is only one constant. One universal. It is the only real truth. Causality. Action, reaction. Cause and effect.
Twitter:Merv Chat:irc.teksavvy.ca


HiVolt
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said by TwiztedZero:

I'm not too worried about 64QAM, that'll come when they fix the node I'm on eventually, theres got to be hundreds of nodes all thru a single POI so this, I don't expect will happen overnight.

It's not all about the local node... My Node was all fixed up and switched to 4x64QAM way back in April or so, then a few months ago I was switched to the Comstock POI, and I've been on 4x16QAM ever since... Its probably further up the line in my case...
--



sbrook
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Waimea, your problem is NOT the same. You were getting T3 timeouts, which are distinctly different from T4 timeouts which merovingian gets.


Waimea

join:2010-06-30
Toronto, ON
I noticed that they were T4 timeouts as opposed to the T3s I had. I'm no network specialist but I've been following this thing pretty closely since rogers started mucking about with the bonding. I can't help but suspect that there is some correlation between both, namely that the cmts isn't responding back to the modem and causing the reset in the cable interface.

I'm sure most of you are familiar with these by now but it doesn't hurt to post them again:

T3 ( Ranging Request Retries Exhausted )

Explanation: The cable modem has sent 16 Ranging Request (RNG-REQ) messages without receiving a Ranging Response (RNG-RSP) message in reply from the CMTS. The cable modem is therefore resetting its cable interface and restarting the registration process. This typically is caused by noise on the upstream that causes the loss of MAC-layer messages. Noise could also raise the signal-to-noise ratio (SNR) on the upstream to a point where the cable modem’s power level is insufficient to transmit any messages. If the cable modem cannot raise its upstream transmit power level to a level that allows successful communication within the maximum timeout period, it resets its cable interface and restarts the registration process. This error message is DOCSIS event message is R03.0, Ranging Request.

T4 ( Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received )

Explanation: The cable modem did not received a station maintenance opportunity in which to transmit a Ranging Request (RNG-REQ) message within the T4 timeout period (30 to 35 seconds). The cable modem is resetting its cable interface and restarting the registration process. Typically, this indicates an occasional, temporary loss of service, but if the problem persists, check for possible service outages or maintenance activity on this particular headend system. This error message is DOCSIS event message is R04.0, Ranging Request.


Source: »volpefirm.com/blog/docsi ··· iptions/

Both cite Ranging request as the initial source of the issue. for T3, the modem doesn't get a response after multiple tries and then resets; with T4s the modem doesn't even get a chance to send the ranging request.

Both instances could be caused by signal noise or something that prevents the CMTS from talking to the modem. Or Am I reading it wrong?

edit: To Merovingian, I don't think you can have any effect on who shows up from Rogers, lke they say in french tu vas devoir prendre ton mal en patience until you get a good one. altough one of the techs did tell me that you could escalate it after a few tries to get a more senior level tech in there. Can't quite recall what he called it though.

--
Proud Teksavvy customer since 2007


sbrook
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T3 timeouts are very common during the modem restart process if there's a line problem, since ranging is an integral part of that process.

T4 timeouts occur during operation and result in a modem restart and hence ranging.

IF there were a line issue, even an intermittent one, one would expect with all those T4s causing rebstarts, a T3 timeout would occur during the restart.


TwiztedZero
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Lots of line noise is my wild guess of the day. Starts around 8am sometimes a little later - and goes on all day long then near to or just after 2am *poof* everything stablizes until the next morning. Ofc thru some of those overnight hours theres the random odd reboot but its steady enough then to stay in irc or do a little streaming. This past weekend its been next to impossible to do that during the daytime hours. Its almost like theres some kind of interference on my line someplace along the way.

Ofc we know most regular people are sleeping and such during the overnight hours so that does indicate its the line someplace.

Its done this ofc three or four times while I typed this short post. Gives you an idea how dismal it is eh?
--
You see there is only one constant. One universal. It is the only real truth. Causality. Action, reaction. Cause and effect.
Twitter:Merv Chat:irc.teksavvy.ca