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robhouston

join:2001-09-15
Chester, NJ

Post-Sandy Modem or Comcast Problem??

Hello, All:

My power, cable TV and internet were down for about 12 days as a result of Hurricane Sandy. I have a customer-owned SB6120 modem, and since cable came back up several days ago, I have to reboot the modem 5-6 times a day to restore internet connectivity.

During these events, the modem lights continue to blink and there is no loss of TV signal, but I cannot access the GUI webpage of the modem to check the error messages or status. Once I reboot the modem, everything returns to normal until internet connectivity is lost again several hours later.

Signal levels to the modem are the same as before Sandy and are within normal expected ranges.

So, I'm perplexed-----does this sound like some kind of post-Sandy Comcast network problem, or does this sound like an issue with my modem?

Thanks!



Mike Wolf

join:2009-05-24
Beachwood, NJ
kudos:3

I would ask around your neighbors and see if they are seeing the same issue as its very possible its a Sandy problem if others in your area are having the same problem.



NetFixer
Snarl For The Camera Please
Premium
join:2004-06-24
The Boro
Reviews:
·Cingular Wireless
·Comcast Business..
·Vonage
·Comcast

1 recommendation

reply to robhouston

If Mike Wolf's ask your neighbor advice doesn't provide an answer, try connecting a static IP configured PC directly to the modem the next time it locks up. Setup the PC's NIC to use an IP address of 192.168.100.200 with a gateway address of 192.168.100.1 (don't worry about the DNS IP addresses). If you still can't connect to the modem on »192.168.100.1 then there is a problem with the modem or its power supply (or possibly even the ethernet cable). Was either the modem or its power supply under water at any time during or after Sandy's passage?
--
We can never have enough of nature.
We need to witness our own limits transgressed, and some life pasturing freely where we never wander.



EG
The wings of love
Premium
join:2006-11-18
Union, NJ
kudos:9
reply to robhouston

FWIW here, some makes and models of modems need to actually be in block sync mode with the system in order to be able to access their user interface pages.

Have you tried to access them when the "Online" indicator light is lit solidly ?


robhouston

join:2001-09-15
Chester, NJ

Thanks to all for the suggestions. I haven't had the chance to check with neighbors, but I'll do so. No, nothing was underwater, since the part of NJ in which I live had a wind event only. I'll try connecting directly to the modem. Yes, indeed, I've the "online" indicator light is lit solidly when I can't access the interface page.

Thanks to all, and I'll continue to troubleshoot this problem.


boontonflyer

join:2004-07-05
Ringoes, NJ
Reviews:
·Comcast

1 edit
reply to robhouston

I have run into a similar problem with a Netgear WNR3500L (Sam Knows FCC project) running behind an Arris Touchstone TM722G DOCSIS 3 modem. My case is that if I "power cycle" the router it never re-establishes connectivity with the modem until I do the "pinhole reset" on the cable modem. I have been attributing this problem to a "defective" router but don't know this is absolutely the case. I run off a UPS so I'm pretty sure that power interruption is not in the "mix".

Are you running your equipment from a UPS (Uninterruptible Power Source)? If not you might be experiencing momentary power interruptions (in a "post Sandy" surge environment).

FWIW

Paul
PS: Only installed this modem (supplied by Comcast) at the end of September so I don't have a lot of anecdotal experience with this modem type.



NetFixer
Snarl For The Camera Please
Premium
join:2004-06-24
The Boro
Reviews:
·Cingular Wireless
·Comcast Business..
·Vonage
·Comcast

said by boontonflyer:

I have run into a similar problem with a Netgear WNR3500L (Sam Knows FCC project) running behind an Arris Touchstone TM722G DOCSIS 3 modem. My case is that if I "power cycle" the router it never re-establishes connectivity with the modem until I do the "pinhole reset" on the cable modem. I have been attributing this problem to a "defective" router but don't know this is absolutely the case.

I don't think your SamKnows box is defective, I think that is just a symptom of how it works when it is not behind a NAT router. I had my TP-Link WR1043ND SamKnows box lock up and block all IP traffic to the Internet (and to the cable modem) numerous times when it was located between my cable modem and the rest of my network. I finally had to tell SamKnows to remove me from the program it started happening so often.
--
We can never have enough of nature.
We need to witness our own limits transgressed, and some life pasturing freely where we never wander.

boontonflyer

join:2004-07-05
Ringoes, NJ
Reviews:
·Comcast

You maybe right. I have sent message to Sam Knows re: this problem and "degrading wireless speed" every 4-5 days until I "power cycle" the router. That is how the other problem reared its "ugly head". Waiting for feedback from Sam Knows !

Thanks,

Paul



NetFixer
Snarl For The Camera Please
Premium
join:2004-06-24
The Boro
Reviews:
·Cingular Wireless
·Comcast Business..
·Vonage
·Comcast

3 edits

said by boontonflyer:

You maybe right. I have sent message to Sam Knows re: this problem and "degrading wireless speed" every 4-5 days until I "power cycle" the router. That is how the other problem reared its "ugly head". Waiting for feedback from Sam Knows !

Thanks,

Paul

I did not see the lock up problem with my SamKnows box when it was behind an SMCD3G gateway (where it got its WAN IP address from the SMCD3G's DHCP server instead of from Comcast). Shortly after I started using an SB6121 standard cable modem, I started seeing the intermittent lockups. I also saw that symptom when it was behind my backup DCM202 modem. When it would lockup, I had to power cycle both the modem and the SamKnows box to get it to work again (sometimes I would have to do that several times before it would work).

I did find that if I put the SamKnows box behind a NAT router and used it as just a standalone LAN device, that it did not interfere with my network, and the tests would still run. However, I noticed that most of the test results were noticeably slower than when it was the first device in the chain, and I felt that was not really fair to Comcast or to the program, so I had myself removed from the program.
--
We can never have enough of nature.
We need to witness our own limits transgressed, and some life pasturing freely where we never wander.

boontonflyer

join:2004-07-05
Ringoes, NJ
Reviews:
·Comcast

I may end up removing myself from the program (after I find out what Sam Knows response is.

When you removed yourself did they request return of the router??

I've gotten used to using the guest account (unsecured) and the regular account (secured) to protect the network. I have five other (not computer savvy) users plus additional family/friends that the "guest account" provides sufficient access for their needs. Also run a Windows Home Server so I don't worry about files getting deleted / corrupted in the public areas. I can restore them very easily from the previous days "backups" if necessary.

Thanks,

Paul



NetFixer
Snarl For The Camera Please
Premium
join:2004-06-24
The Boro
Reviews:
·Cingular Wireless
·Comcast Business..
·Vonage
·Comcast

said by boontonflyer:

I may end up removing myself from the program (after I find out what Sam Knows response is.

When you removed yourself did they request return of the router??

I was told that I should dispose of my TP-Link box in an environmentally friendly way. I don't know their policy for your Netgear box (but I suspect that they would consider it expendable).

I decided to recycle the TP-Link box (can't get more environmentally friendly than recyclying) by loading the original TP-Link firmware just to see how it worked as a plain router. I did an OpenWRT safeboot to get root telnet access and I loaded the current TP-Link firmware that I got from their web site. I saw all of the expected messages on the console, and it reported that the new firmware would be activated after a reboot. I rebooted and the device just died; it was totally bricked. I later learned that the hardware version of the WR1043ND that I had could not be reverted to the current TP-Link firmware once OpenWRT had been installed (it clobbers the bootfile), and that I should have just loaded a generic OpenWRT package instead. It appears to have a JTAG interface, so it might be possible to recover the boot capability that way, but for a sub $50 dollar router, that would probably be more trouble than it is worth.
--
We can never have enough of nature.
We need to witness our own limits transgressed, and some life pasturing freely where we never wander.

robhouston

join:2001-09-15
Chester, NJ

Yes, I was on the Sam Knows program, too. When I removed myself from the program earlier this year, they didn't want the router back, so I reflashed the firmware to stock Netgear and continued to use it. When I continued to have some problems with the WNR3500L, I replaced it with the WNDR4500 router, and the problems disappeared. However, the problem I'm having now appears to be related to the modem, but not the router.

In answer to an earlier question, I have the modem on a UPS and I'm not having any post-Sandy power issues.

Thanks for the answers!


robhouston

join:2001-09-15
Chester, NJ

Okay, so the problem is solved. I checked with a couple of neighbors, and indeed, they were having the same problem. In addition, the problem recently stopped happening, and we haven't had this problem occur in over 48 hours now.

So, I've concluded that the problem can be chalked up to a post-Sandy Comcast issue and has been resolved.

Thanks to all for your posts and suggestions.



dmk08809

join:2001-09-08
Clinton, NJ
Reviews:
·CenturyLink
·Vonage
·Comcast
·Embarq Now Centu..

Sounds eeriliy similar to what happened w/ my Comcast internet service here in Clinton. I have a Zoom 5341J and even though the DS signal levels were good, the problem apparently was with the upstream. I'd get continual unicast ranging errors, heavy loss of traffic passing, and latency/jitter all over the map. I talked with a neighbor who has Comcast digital voice and she told me it was practically unusable.

A couple weeks ago I had a tech dispatched (11/6) and he told me the system's plant was a mess after Sandy. He also said it would be ~2 weeks before stability would likely return -- he mentioned stomthing about the plant running at 3% where it should be in the 90's. (no idea what he was referring to there and probing for more specific details was fruitless).

In any case, as of 2 days ago (Thursday 11/15) the ranging problems stopped and things truly do seem back to "normal" now. I just hope it stays that way!



flwpwr

@comcast.net
reply to robhouston

levels and error logs?

the only thing off the top of my head if you had to move stuff around make sure you got the RIGHT power supply with the modem and not something else's PSU.



beachintech
There's sand in my tool bag
Premium
join:2008-01-06
kudos:5
reply to dmk08809

Market Health numbers most likely. From what I have seen talking with techs up there, they are back up and running and most areas, and have only pockets of issues still rather than most of the state.
--
Ex-Tech at the Beach.
I speak for myself, not my former employer.



EG
The wings of love
Premium
join:2006-11-18
Union, NJ
kudos:9
reply to flwpwr

said by flwpwr :

levels and error logs?

He stated that he "can't access them"..


SeaSeaTee5

join:2010-05-06
Maryland
reply to dmk08809

That would most likely be Plant Integrity. 3% would mean only 3% of the modems in that node are within spec. With that many modems out of spec, they were probably having upstream SNR issues.

I was in NJ for a week helping restore service. Tons of drops down and lots of damaged cable and power plant. It took a couple of weeks to get most of the outages cleared, then they can start tracking down plant integrity issues.



dmk08809

join:2001-09-08
Clinton, NJ
Reviews:
·CenturyLink
·Vonage
·Comcast
·Embarq Now Centu..

Thanks for the explanation -- now that actually makes sense!

Yeah, it was a bit of a mess around here. Fortunately the worst is now behind us. Because of crews from out of the area such as yourself (for power, cable, phone) the utility recovery was I think handled quite admirably. Many who complained, IMO, simply didn't account for the fact this was truly a catastrophic once-in-a-generation event. Thanks to you and your fellow utility cousins life has begin to resemble normalcy again for most of us. Down the shore however, ugh... its total devastation that'll take years to rebuild.



flwpwr

@comcast.net
reply to EG

said by EG:

said by flwpwr :

levels and error logs?

He stated that he "can't access them"..

robhouston said:
During these events, the modem lights continue to blink and there is no loss of TV signal, but I cannot access the GUI webpage of the modem to check the error messages or status. Once I reboot the modem, everything returns to normal until internet connectivity is lost again several hours later.

Maybe I don't read so well, or maybe he can get the data I requested when its running NORMAL. But I digress, why try to help.


EG
The wings of love
Premium
join:2006-11-18
Union, NJ
kudos:9

said by flwpwr :

But I digress, why try to help.

Is that a rhetorical question ??


Mike Wolf

join:2009-05-24
Beachwood, NJ
kudos:3
reply to dmk08809

I only hope that this time around Comcast will actually put in quality top of the line brand new equipment instead of the cheap stuff they got from the lowest bidder. 802.11n 450Mbps Wi-Fi hotspots hopefully.



beachintech
There's sand in my tool bag
Premium
join:2008-01-06
kudos:5

They will until they get to your neighborhood, then its back to the used stuff they bough from Mediacom.
--
Ex-Tech at the Beach.
I speak for myself, not my former employer.



Mike Wolf

join:2009-05-24
Beachwood, NJ
kudos:3

damn it. my neighborhood in particular? We're not having any issues now that I'm finally home except that the IPv6 DHCP lease time is only 60 minutes instead of the 4 days I normally get.


robhouston

join:2001-09-15
Chester, NJ
reply to robhouston

So, the problems started again a few days ago. Every so often, the modem will reboot by itself or lock up, requiring a reboot.

The error in the modem log is "Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-"

Signals are Downstream - SNR 36dB, Power Level -6dBmV; Upstream - Power Level - 49dBmV. So, I think these are good.

I've swapped out the modem with a new one, and I'm continuing to have these issues, so I think that rules out the modem as the problem.

Any ideas about what is causing this?

Thanks!



beachintech
There's sand in my tool bag
Premium
join:2008-01-06
kudos:5

Without being there with a meter, not really. Call for a service visit.
--
Ex-Tech at the Beach.
I speak for myself, not my former employer.


robhouston

join:2001-09-15
Chester, NJ

Thanks, but the problem is intermittent, meaning that it's likely nothing will happen for the short time a tech is here.

That said, if this continues, I'll have no choice but to call for a tech.



dmk08809

join:2001-09-08
Clinton, NJ
Reviews:
·CenturyLink
·Vonage
·Comcast
·Embarq Now Centu..

Yeah Rob, I'd bet our problems are unrelated . . . but . . . After being stable for nearly a week its starting to come off the rails here again too. Am now seeing periodic bursts of ranging errors - end result is excessive latency, jitter, and packet loss. The problem here existed before Sandy intermittently, eventually the storm hit & service was down for a ~week+, then things slowly improved.

I've already had 2 tech dispatches before & after the storm. Each time they've promised its been fixed after doing something somewhere (they wouldn't reveal what). I tried engaging ComcastSteve but I think he gave up after several unsuccessful volleys back-and-forth. I really don't know what else to do at this point but suppose will try yet another dispatch or maybe seek out the mythical Comcast executive support group to see if they can do anything. I don't wanna drop the service and go back to DSL, but at least that worked reliably (even if a tad slower)!

Its really amazing at just how fragile this technology is for a 3rd generation product; or perhaps maybe how poorly its implemented here resulting in all these chronic problems. At least I know its not just my service -- the neighbors also complain but have been (beaten?) into being complacency and accept the lousy service even for choppy & broken up CDV voice services!

*sigh*



beachintech
There's sand in my tool bag
Premium
join:2008-01-06
kudos:5
reply to robhouston

You'd be surprised what a good tech can see with their meter. Call in for service, and keep calling until it's resolved.
--
Ex-Tech at the Beach.
I speak for myself, not my former employer.



Zeo

@comcast.net

I too was having high latency and jitter since around the time of Sandy and have been troubleshooting this since. I also like you replaced my modem. I was using a Moto 6120 and bought a new Moto 6121 and had the same exact problems. The 4 visit from techs he tried a Ubee modem from them and it has been working good. I think there is something going on with Moto modems on Comcasts end. What brand are you using?