Cable modem losing connection all the time during peak hours.

[Nebbers]

What's usually the culprit here?

The cable company automatically blames the router because my signal strength is very good with the modem. Well, that's a possible cause, but this router has been fine for a long time until recently. Additionally, this seems to almost always happen during peak usage hours like 5-9 PM in particular. Mid afternoon around 3PM as well but not near as much as the evening.

This happens regardless of what I'm doing. It's not torrents, or even heavy bandwidth use. Sometimes I'll just be browsing or something not bandwidth-intensive and it'll drop the connection. Unplugging the cable modem for a minute and then plugging it back in *always* fixes it.

I'm thinking maybe there's a signal problem at certain times or maybe there's just something borked on their end, but both of those seem unusual because when it's working right it's pretty damn fast. I get downloads at or above the advertised amount I'm paying for, 3MB/sec or more, when it's working right. Also, this basically never happens from midnight to 6AM.

I should add that this happens with more than one router, I've been using a Dynex wireless router but switched it out for an older Linksys just to see (I've had more issues with Linksys stuff in the past than anything else). When it happened in the past, maybe a year back, I tried directly connecting to one PC and it changed nothing. Eventually the problem just sort of went away for a while.

Is it possible that wifi interference or something with that could make the whole connection drop, even when no wifi devices are being used? The only things using wifi are a media player and a Kindle, and this happens without either of those present.

Realize this is a pretty broad description but maybe there's something I'm not aware of I could check out.

Edit: Also just realized I'm not posting this in the right forum. My bad.

 

[MichaelD]

Signal strength does not tell the whole story, not by a long shot. Typical Tier 1 response, blaming the router. Had a similar problem years ago; the ISP had a problem with their DNS servers. They blamed my router when it was their DNS servers. But anyway, it could be that your router is going bad, but the odds of it dropping the connection at the same time every day is slim. Plus you switched routers and the same thing happens.

Possibly during that timeframe the ISP is rebooting things downstream or forcing a DHCP renewal and your router doesn't like what it sees. Not exactly a technical explanation but you get the idea. I lived overseas for 5 years. Every day b/t midnight at 1:00AM something in the ADSL chain of devices was rebooted b/c I'd lose my ADSL signal for about 5 minutes and it would come back like clockwork. I had a guaranteed 23:55 of uptime per day. LOL! This happened every day. It gave me an opportunity to refresh my drink though.

If you plug straight into the modem does this happen?

 

[Nebbers]

Going to try that later today when the problem hours come around, but it's sort of a problem because three people definitely need access most of the time.

I'm actually using OpenDNS servers instead of the ISP's, doesn't seem to make any difference either way with this problem though.

... what's the go-to router brand these days? Long ago, Linksys seemed good but I had two different Linksys routers completely die on me and stopped buying them after that. This Dynex one was actually like 8 bucks and worked great for a while, but I guess I don't know if it's the culprit just yet.

The best router I ever had was an old Pentium 2 that I installed something on... forget what, it was long ago.

DD-WRT on something, perhaps? Keep seeing that mentioned lately.

It just seems odd to me that it would be the router, as all I have to do is unplug the modem briefly and it's fixed. I don't need to reset the router, and just resetting the router doesn't fix it. Seems to be all in the modem or somewhere beyond...

 

[Nebbers]

Should also mention I've tried virtually every possible combination of router settings and nothing seems to make any difference. Disabling/Enabling uPnP, turning off the Wireless completely, QoS, a bunch of stuff I'm not even sure I understand... always the same problem regardless.

Sucks because other than this, their service is outstanding. I think it's one of the best cable ISPs in the country for the price (MidcoNet)

 

[Hankysmoo]

Do you have an amp and/or cable tv? It's possible your signal is too strong which can cause outages. I would ask a cable technician to come out and check your signals.

 

[JackMDS]

First investigate the issue with wire connected computer (Not Wireless), try to connect directly one computer to the Modem by itself.

If one wired computer on the Modem without a Router shows the same behavior, insist that they should send a technician to measure the signal out of your modem at your location.

The ISPs extremely exaggerate their claims of what their central computers can evaluate at the remote aspects of the connections.

Happened to me more than once that something was wrong at their central switches DSLAM, and they keep insisting that their computer shows that my devices are the root of the problem.

 

[Modelworks]

Had this issue with charter. The modem randomly reset during various times of the day no matter if in use or not. Continued to do this for a week . Signals looked good. What they did is attach a device that is a line monitor. It records signal levels and status 24/7 over a period of days. It found it wasn't my modem but a problem with the headend.
Intermittent issues are the hardest ones to catch.

 

[Despoiler]

Have you talked to tech support? Usually issues like that are signal issues for when people get home. It could be device interference from someone else near you. It could be a buggy firmware that got loaded to your modem. I had that issue. It would randomly lose sync an was a known firmware bug. Lots of things. As someone mentioned the cable company can put a 24/7 monitor with short polling intervals to help diagnose the issue.

 

[ImDonly1]

Go to http://192.168.100.1 and check the signal under one of the tabs. You can post it here if you are not sure what it means.

There is also a log tab that will tell you what the modem was doing or what error it received at what time. You can post some of that here, but edit out your mac address.

 

[Nebbers]

The log doesn't seem to go back very far at all, but here are some of the messages that were around an outage that happened early this afternoon:

No Ranging Response received - T3 time-out

Init RANGING Critical Ranging Request Retries exhausted

Started Unicast Maintenance Ranging - No Response received - ... (this one repeats a lot)


Eventually:

Wed Oct 19 13:18:32 2011 Wed Oct 19 13:18:32 2011 Information (7) IP init completed ok
Wed Oct 19 13:18:32 2011 Wed Oct 19 13:18:32 2011 Information (7) CableModem TFTP init ok
Time Not Established Time Not Established Information (7) CableModem DHCP client init ok
Time Not Established Time Not Established Information (7) MAP w/initial maintenance region received
Time Not Established Time Not Established Information (7) Downstream sync ok
Time Not Established Time Not Established Information (7) Beginning initial ranging...
Time Not Established Time Not Established Information (7) downstream time sync acquired...
Time Not Established Time Not Established Information (7) Downstream sync ok
Time Not Established Time Not Established Information (7) Received a UCD message!
Time Not Established Time Not Established Information (7) starting ds time sync acquisition...
Time Not Established Time Not Established Information (7) Received a UCD message!
Time Not Established Time Not Established Information (7) Locked on the downstream. Waiting for UCDs...
Time Not Established Time Not Established Information (7) Downstream lock ok
Time Not Established Time Not Established Information (7) Sync Start


We do have cable TV, yes.

Note: The stuff on the top is in order of occurrence (I put it chronologically) but the bulk of it at the bottom is direct copy & paste, it's backwards

 

[Nebbers]

As for the signal... there's a great deal of information that I'm really not familiar with.

Downstream Lock : Locked
Downstream Channel Id : 53
Downstream Frequency : 603000000 Hz
Downstream Modulation : QAM256
Downstream Symbol Rate : 5360.537 Ksym/sec
Downstream Interleave Depth : taps32Increment4
Downstream Receive Power Level : 1.7 dBmV
Downstream SNR : 36.3 dB

Upstream Lock : Locked
Upstream Channel ID : 3
Upstream Frequency : 33008000 Hz
Upstream Modulation : QPSK
Upstream Symbol Rate : 5120 Ksym/sec
Upstream transmit Power Level : 41.2 dBmV
Upstream Mini-Slot Size : 4

There's one more tab with more, but it's a mess without some formatting. If none of this is helpful I'll format the rest.

 

[Nebbers]

Modulation Type, Differential Encoding, Preamble Length, Preamble Value Offset, FEC Error Correction (T), FEC Codeword Information Bytes (k), Scrambler Seed, Maximum Burst Size, Guard Time Size

That's what's on the other tab -- but like I said, it comes out as a mess if I just copy and paste it without some formatting. Most of this stuff is greek to me.

 

[bobdole369]

Downstream SNR : 36.3 dB

This is one of the most important bits of information.

http://www.dslreports.com/faq/5862
(scroll to SNR) - 30+ is required, 33 is excellent, your 36 is twice that of excellent. This is why the tier 1 folks are saying "no problem".

It doesn't however paint the whole picture. For DOCSIS to work effectively (and the cable plant, both video and data) it requires a completely closed system. That is no breaks in the coax, no leaks, no water ingress into the cables, etc.

Downstream Frequency : 603000000 Hz
Upstream Frequency : 33008000 Hz

Downstream is at 603mhz. What else is on 600ish mhz that can interfere? Not much at all, but that doesn't mean that something is happening on 600mhz somewhere.

33mhz is the upstream, which is just above shortwave radio. This is typical for DOCSIS, not an issue, however those signals down low are significantly more susceptible to interference from electrical stuff.

In all likelihood - some issue exists with cabling, be it from a cable on the pole heating up, to maybe the local device in your neighborhood overloading or getting hot from the sun at a particular angle, or maybe some neighbor runs the air during that time and it happens to be that your feed is wrapped around his AC electrical line and theres a bad cap on the motor. None of these things are something you need to worry about.

You shouldn't drop it, be persistent, and call *every* single time it happens. Ask for a resolution, complain to the tier one that this happens all the time. Of course they'll replace the CM first, eventually they'll send out a truck and fix their own issue.

 

[Gibson486]

Well...I had a different tech issue. They said it was my router also. I was always being wall gardened, except when the cable modem went directly to my laptop. I would always spends about 2 hours on the phone every other week. Then I tried all the tricks like MAC spoofing, changing the DNS server, etc. I finally gave up and just got a new router. It works now without any help from their end. So, just saying...is it worth spending hours on end "fixing" this issue when you might be able to spend $50 to fix it right away?

edit:

NM...i read the whole thing. If it is happening with different routers, yeah, it's probably the cable company.

 

[Midwayman]

I had something very similar happen with my connection, but it was mostly packet loss. I logged pings for several days and could show the packet loss % going up with prime time. Clearly their router was overloaded. I tried for awhile to get it fixed. Got the usual your signal is fine stonewall. Lucky for me, I had more than one cable operator and just switched. The real challenge is getting someone who really knows what they are talking about on the line. Level 1 techs never can solve this sort of stuff.

 

[ImDonly1]

Signal is fine. Bottom part of logs you pasted is just the modem coming back online and is normal after losing connection. The top part are errors. Like mentioned above, I would just keep calling them. Eventually they might send a higher level tech to check it out. You can try replacing splitters, etc or just let them take a look at it.