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Sivar

Bizarre cable internet problem

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Every night at about midnight, the cable modem mysteriously loses its connection for 8-10 hours, and can be observed reconnecting to the cable network continuously during that time. The disconnection isn't always at midnight, once it was at 10:30, but that seems to be its favorite.

The cable modem was replaced with a Toshiba 1100 which is known to work perfectly, but to no effect. The cable signal strength was tested at about -15dB, which should be fine, and after a cable replacement with some premium RG6, the interference level is quite low.

I have been completely baffled by this problem, and the cable company really has no idea either. No one else in the area has similar problems, but the signal is passed to this house without problem, and the picture quality of the cable is just fine (at least, just fine for cable television).

This is not exactly a neighborhood in which cable theft would occur, and all diagnostics I an d the cable company have run indicate that everything is peachy, except for the cable modem's recorded connection times.

Staying with cable is preferable to DSL for speed, price, and not-paying-Quest-a-dime reasons.

So the question is: Would anyone care to share theories as to what is going on? What could cause a cable connection to die at nearly the same time every night, for about 8-10 hours, and reconnect perfectly without issues for the rest of the day? And only for this particular account? (I have spoken with several others at various locations which have not had similar problems).

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hehehe Sounds like this one story I heard from a work associate. I work for the phone company so take from this what you will. THis person got new phone service turned on in his brand new house. Well, his phone worked fine from about 8 or 9 in the morning till about 6 in the evening. He went round and round with the people at the phone company about this. No one knew why this was happening. Funny thing, they found out the computer system every morning would spit out a connect order to the CO tech and he would turn the phone line up. Then that afternoon the system would spit out a disconnect order and the CO Tech would turn the phone off. This happened for a week straight. Funny Computers.

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As a cable tech I can tell you that -15db is the minimum for signal strength in our area. If your connection DHCP? Check for when your last IP lease was obtained. If it's at those time then there probably is a problem with their DHCP server. If it's only happening recently then it may be caused by the slammer virus that's still in some of the systems.

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Why switch to half the speed for the same/higher price? I had DSL for 2 years before going to work for AT&T and it was slow. I also had to put filters on all my phones and the modem was USB. I still get over 2mb/s and almost everyone in my neighborhood is on cable.

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Ya, Cable Modems suck. If you have the chance, change to DSL. I know its not available in many locations, but haveing had both cable modem, and DSL, I think DSL is far better.

I strongly Disagree on these. Cable are far beter and faster than DSL. I'd have use them both and now only Cable Modem for both at works and home. I used to get any where from 5MB/S to 6Mb/S download when It was Excite or @Home.com but when AT&T Took over, download speed dropped to 1.5Mb/S, that's about 250 to 300KB/S in the real world! :) Still far better than DSL 650Mb/S to 1Mb/S, in real world DSL Download you would be lucky to get 50KB/S! :( I've try both Microsoft/Quest and Verizon DSL for business use and ended up with Cable Modem.) Now, AT&T/Comcast Download speed are up their connection and Download speed to 3Mb/S and I get better than 400KB/S Download speed for both Home and office 8)

DSL still uses Phone line to carry wideband broadband and No way DSL Telephone line will ever do better than Cable modem. 1 1/2 Years with DSL is a long time, Too slow download & connection, too long for me and my works. Thanks to Cable Modem, My download speed are far faster. :wink:

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DSL Cost more if you request higher speed, if yes if you ever gonna to get any higher speed as they advertised. :twisted:

$39.95 per month for Cable with no limit speed :wink:

$69.99 Per month for DSL With 600Kb/S or around 40KB/S Download speed. $89.99 for Gold package that they claim 1Mb/S, $149.99/Month for 1.5Mb/S :evil: You'll never get any where near that from the good Ole Telephone line. A friend just canceled his "Gold" package connection which he never get anything better than 40KB To 50KB/S Download. He could not get Cable Modem because Cable's not aviable at his new house. well, at less not right now.

Here is Seattle, Washington area where cable modem are getting bigger and bigger everyday, DSL is soon will be History. None of my business associate that I know off still using DSL, they are all switched to Cable!

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Is your cable line split between a TV and your cable modem? Splitters can screw with the cable and cause it to go out. Sometimes it doesn't happen immediately and can take up to several months to cause problems.

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DSL Cost more if you request higher speed, if yes if you ever gonna to get any higher speed as they advertised.  :twisted: 

  $39.95 per month for Cable with no limit speed  :wink: 

  $69.99 Per month for DSL With 600Kb/S or around 40KB/S Download speed. $89.99 for Gold package that they claim 1Mb/S, $149.99/Month for 1.5Mb/S  :evil: You'll never get any where near that from the good Ole Telephone line. A friend just canceled his "Gold" package connection which he never get anything better than 40KB To 50KB/S Download. He could not get Cable Modem because Cable's not aviable at his new house. well, at less not right now.

  Here is Seattle, Washington area where cable modem are getting bigger and bigger everyday, DSL is soon will be History. None of my business associate that I know off still using DSL, they are all switched to Cable!

This is not an accurate representation of the costs for DSL (at least, not in my area). In addition, last time I checked, 600Kb/s is around 80KB/s, not 40.

I have VerizonDSL, and currently get 768/128 for $50/month, not $70. And yes, I get about 95KB/s most of the time (assuming I'm connecting to a site with the bandwidth to support that). Bear in mind that the speed you get from DSL is dependent on how close you are to a CO.

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Oh, one last thing: according to The Inquirer, anyway, a new DSL chip is good for up to 20 Gb per second (not that most DSL users will see this in the next few years).

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Ok. Here we have the choice between shaw cable, and telus DSL (Phone Co.)

Telus cost 24.95 for the first 6 months and 34.95 after that. Cable modems cost about the same.

There are several problems with cable modems (here):

1) service interuption that can last for days.

2) lax (non-existant) security. (at least telus tries to protect its customers with firewalls, cable modems have no security infastructure at all)

3) Predictable speed. cable modems effectiveness can vary widely.

with my plan on telus dsl, I get 2.5 mb/s down and 640 kb/s up. and thats always at my beck&call.

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ok guys, cable and dsl are both good. the point is to have some kind of broadband.

cable can usually achieve better download rates and lower pings. i had cable for 2 or 3 years (beta tested the one-way stuff for charter until they got up to speed) and i was largely satisfied with it.

dsl is usually subjected to content filtering, download caps, or private server restrictions and offers much cheaper static ips. i've had that for over a year and i'm extremely satisfied with it, and the people at covad seem to know MUCH more about their product than charter.

i think it basically comes down to what kind of user you are: a gaming/p2p guy or a networking guy

while i play a steady amount of q3 promode and warcraft3, my vote easily landed on covad's 1.5/384/static ip service with no restrictions.

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Is it just me or did we stray off topic just a little bit? Sivar and I actually live in the same city and he described, in more detail, what was happending so I just thought I would share. The cable modem is actually loosing connection with the network, so for example when you first boot up your cable modem you will usually see the online light flash, then it will go steady, then the send light and the receive light, then you are online. His just keeps doing it over and over again as if it cannot connect to the cable modem network. I was thinking if we could get logs from the cable modem it might shed some light on the problem. I don't suppose anyone knows how to do this, or even if it's possible.

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lines are affected by weather - i've seen cable and dsl in 'far out' areas get signifigantly worse as HEAT increased, and also get affected by rain

perhaps your backyard is freezing overnight and causing something? has the line from the box to your house been examined?

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Sivar,

Have you try get the tech to check if your cable's properly grounded? I've very similar problems at my house when I first got Cable modem a few years ago. it took 4 weeks to found out this very small thing.

It's Sometime it was working fine and then it just went off with no reason! The signal light flashing, one light then two light then all light flashing none stop. Called AT&T/Excite Tech supports and they sended the tech to my house many time, each time they came Cable modem will works??? well for a few hours and then it stop again! :evil: Called again and upper level supports can't find any problem with signal???

Well, I was gonna cancel Cable modem and cable TV Both and the Cable TV's guy came by to pick up the digital box and then he said, I've got signal feedback from my cable??? :roll:

Anyway, he went out and check with the main box, came back with a big mettal rod and grounded my cable! Wow, what a difference! :lol: My TV's pictures look a lot better, my cable Modem lit up and never have any problem since!( Well,untill AT&T / Excite broke up!)

Just some thought! You may have the same problems and it may works for you. If you call again and ask someone to check if your cable, Cable TV & Cable modem's properly grounded? :?: It might help!

Another thing is, at cable's main box some where... as per Cable TV's guy once told me that, it was loose at the main spritter?

Hope this help and good luck.

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As a cable tech
Glad to have you on SR!
I can tell you that -15db is the minimum for signal strength in our area.
I would bet it is the minimum by their standards as well, but it was working more or less a year ago at +5-10 (with occasional disconnects), and from that perspective -15 doesn't seem so bad . Still, while I agree that -15 isn't great, I would think that it would either not work or work sporadically, not maintain a eerily consistant "scheduled downtime." Of course, you're the cable tech, but increasing signal strength beyond that would probably require rewiring the house. The [....] contractors used '59 cable internally, though I'd think that would still be okay. Actually, I'm not certain of the cabling, but the plastic insulator looked significantly smaller than that of RG6, which IIRC is the main difference between the cable types.

Oh, I would have replied yesterday but... Guess. :)

If your connection DHCP? Check for when your last IP lease was obtained. If it's at those time then there probably is a problem with their DHCP server.
Connected systems and the cable modem use DHCP, but the leases are longer than just a day, and I imagine we use the same DHCP server that everyone else in the area uses, and nobody else is having these odd problems. AFAIK, the company doesn't force a new lease to be obtained every day, and the system has more or less kept the same IP for some time now.

Here's the last entry in /var/db/dhclient.leases :

lease {

 interface "xl0";

 fixed-address xx.xxx.xxx.219;

 option subnet-mask 255.255.248.0;

 option time-offset 0;

 option routers xx.xxx.xxx.1;

 option dhcp-lease-time 1206913;

 option #128 18:74:98:1;

 option dhcp-message-type 5;

 option domain-name-servers xx.xxx.x.82,xx.xxx.x.201;

 option dhcp-server-identifier xx.xxx.x.82;

 option broadcast-address 255.255.255.255;

 renew 3 2003/2/19 23:38:19;

 rebind 3 2003/2/26 03:17:09;

 expire 4 2003/2/27 21:11:34;

}

If it's only happening recently then it may be caused by the slammer virus that's still in some of the systems.
I've considered this, especially since they use Windows servers (at least for their website), but again nobody else in the area has had similar problems, and we've been told that the same servers are used for a rather large area. Generally, access has been imperfect for some time I've been told (I'm just visiting the area), formerly with somwhat frequent brief outages and a handful of 1+ hour outtages.

The company contacted us/them about the fact their logs showed absurd downtimes, then a techcame by, and apparently shrugged his shoulders and installed a booster. Recently another tech came by and found some interference (in addition to low signal strength) and replaced the cable outlet in the wall, refitting the connection, and had us replace and shorten some cabling. That greatly increased signal strength (To -15), but didn't effect the outtage problem in any way.

I had a system constantly ping Yahoo and found that the outtage is quite immediate, no increase in ping times occurs and the connection reliability does not decrease prior to the outtage. In addition, full bandwidth is available until exactly the time that the outtage occurs. After this, judging by the lights, the cable modem loses the connection suddenly and tries to reconnect. It doesn't appear to have any problems reconnecting--the connection light blinks only momentarily (with this modem, the connection light blinks until a network connection is made, and takes a long time if the network doesn't respond). For 1-5 seconds after this, as far as the lights are concerned, everything is peachy, but then it appears to disconnect again and start the process over, an nauseum

Unplugging the modem has no effect. We had the cable company reset everything, reregistered all of the NICs, etc. Nothing.

I would be more frustrated if this weren't such an interestingly strange problem, like the one Quaw described. Of course, I would like to get this fixed before I leave and will slowly be driven mad if the solution is never found.

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lines are affected by weather - i've seen cable and dsl in 'far out' areas get signifigantly worse as HEAT increased, and also get affected by rain

perhaps your backyard is freezing overnight and causing something?  has the line from the box to your house been examined?

The weather here has been unusually erratic, with widely varying temps, but the downtime seems to be unchanged. The line itself tothe house hasn't been examined, but the tech said the sig str and interference levels were "excellent", without numbers, but this tech didn't seem like the type to BS for the company, so I trust he's correct. whether those conditions change at midnight (or thereabout) is an interesting question, but I dont have the equipment and no appointments can be scheduled for that time. There have been days in which the temperature was largely unchanged between uptimes and downtimes, so I don't believe it's weather (though I'm open to anything for such an odd problem)

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Have you try get the tech to check if your cable's properly grounded?
Hmm, I'm not sure if that was checked. I'll have to show your message to the third technician (as well as a few other messages) and have that checked. Thanks for the info.

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Guest russofris

Sivar,

You should have two seperate measurements done on your line. First is signal-to-noise ratio, and second is power. My incomming SNR is 37.5, and my power reading is at 41 ( I have a deal with ATT where I get 3Mbit) and all is well.

Thank you for your time,

Frank Russo

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Sivar, I have a Toshiba pcx 2500.... and I've had a 3com home connect cable modem.. on both you can goto the address http://192.168.100.1 and get your SNR and power level readings from a diagnostic page on the cable modem...

maybe your cable modem will allow the same of you...

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