Losing internet connection during large downloads.

Greetings everyone,
Ill try to keep this short and sweet. I have Charter as my cable ISP.
I have a Motorola SB5120 cable modem. I have had this setup for almost
2 years without any problems at all. Recently (about a month ago) I
began losing my internet connection during heavy downloading and then
about 5 minutes after that it would come right back (don't need to
restart the modem or anything just pops back on). I download from
newsgroups so this was when i first noticed this. After about 5
minutes of heavy downloading my connection would completely disappear,
downloads would stop and i could not get anywhere on the internet. The
strange thing was all the lights on my modem were still lit up.
I figured this must be a problem with my router so i replaced that.
Same thing happened. I figured well maybe my network card was bad,
still same thing. At this point i tried everything. I setup a new
account with a different Usenet server same thing, tried downloading
directly from a website with large files, same thing. Tried a laptop
on my network same problem so now im completely confused and ready to
give up and just live with it.
I decide what the hell i guess i could talk to Charter's tech support.
I was transfered to someone who i could tell immediately could not
speak English to well (not trying to knock the guy Ive come to expect
that now, and he works a lot harder than i do to earn a living so i
respect that). I tried explaining my situation to him and didn't get
very far so he transfered me to on of the head techs. We talked for
about 20 minutes while i my connection crashed and came back up and he
could see i was losing my connection but had no answers. He said he
opened a trouble ticket and that they would be working on it and have
it back up. Well that was 2 weeks ago and I haven't heard anything. I
have looked all over to find some similar issues and cant find
anything. I am hoping one of you out there will be my savior. If you
have any suggestions on what i can do to fix this i would realllly
appreciate it. Thanks in advance.
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I've a hunch that you'll see something interesting in your modem logs: and your signal levels may tell us something: Bob
Reply to
Robert Heiling
Thanks for the help Bob.
I checked the logs and here are the problems that seem to show up:
2007-04-23 19:25:29 5-Warning D03.0 DHCP WARNING - Non-critical field invalid in response 2007-04-23 19:25:29 5-Warning DHCP: Renew: Missing Syslog server 2007-04-20 07:25:29 5-Warning D03.0 DHCP WARNING - Non-critical field invalid in response 2007-04-20 07:25:29 5-Warning DHCP: Renew: Missing Syslog server 2007-04-16 19:25:29 5-Warning D03.0 DHCP WARNING - Non-critical field invalid in response 2007-04-16 19:25:29 5-Warning DHCP: Renew: Missing Syslog server 2007-04-13 07:25:29 5-Warning D03.0 DHCP WARNING - Non-critical field invalid in response 2007-04-13 07:25:29 5-Warning DHCP: Renew: Missing Syslog server 2007-04-09 19:25:29 5-Warning D03.0 DHCP WARNING - Non-critical field invalid in response 2007-04-09 19:25:29 5-Warning DHCP: Renew: Missing Syslog server Here is my signal status:
Downstream Value Frequency 643750000 Hz Signal to Noise Ratio 37 dB QAM QAM256 Network Access Control Object ON Power Level 9 dBmV The Downstream Power Level reading is a snapshot taken at the time this page was requested. Please Reload/Refresh this Page for a new reading
Upstream Value Channel ID 2 Frequency 31392000 Hz Ranging Service ID 27 Symbol Rate 2.560 Msym/s Power Level 37 dBmV
I'm glad this might mean something to you because it is greek to me :). Thanks again Bob.
Reply to
They indicate levels about what your modems is hearing and talking to the headend and how good/noisy the signal.
Signal to noise is indication of quality of the signal.
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Downstream is level that modem receiving (hearing) the signal. Upstream is level modem is sending (talking) to headend.
It looks like your headhend is SCREAMING at you :( and you are talking at a normal level to the headhend. :)
Values from my setup.
Motorola Surboard SB5120 QAM 256 (Working range, my norm) Down Power -4 dBmV (-10 to +10 dBmV, -1 dBmV) SNR 37 dB (higher than 33 dB, 37 dB) Up Power 43 dBmV (30 to 55 dBmV, 44 dBmV)
Reply to
Bit Twister
IMHO, 9 dBmV Downstream is perfectly acceptable. The rest of the levels look good to me, too.
I would continue to check the levels periodically to see if they fluctuate. It's possible they're intermittently moving outside of the working range for short periods.
Reply to
Bill M.
I had a similar problem, losing connectivity. Mine was not related to large downloads though. I was convinced that the problem was between the ISP's distribution point and my connection at the pole. We would experience intermittent dropouts throughout the day. I used a program called Link Monitor, available for free from
formatting link
What I did was ping yahoo.com every 15 sec. and kept a log of the results. I took it over to my neighbors house, we share a distribution box at the pole, and ran the program. It helped me prove that the problem was from the pole to my computer. The ISP's service people were never able to see the problem because it was so intermittent. I went thru 3 cable boxes. The final fix was for them to replace every connector and device in the distribution box where the cable entered my house. It had a feed thru and a 1 to 3 splitter. Good luck, I know how frustrating it is.
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logs:> >
I had been expecting to see the remnants of one of those re-boots in the modem log and the log contents are not consistent with the problem you're describing. Since I would expect that you would be reporting all this fairly close after one of the events, I don't expect to see a two week old entry in the log.
My preliminary conclusion is that your modem connection is working just fine, that's one reason your lights remain normal and these "disconnects" have nothing to do with your modem connection.
Charter must have some more serious problems or the newsgroup service you use might be the problem.
Reply to
Robert Heiling
Thanks for all the feedback, I really appreciate the help. Just for peace of mind I ordered a new modem yesterday and it should be in today. One thing I noticed is that if i throttle the speed down to about 1MBs in my newsgroup software it runs perfect right at 1MBs without any problems. When i take the speed limiter off my download speed fluctuates between 100k and a little over 1MBs and will then drop completely as described in my original post. I have 10Mbs download speed and its been a while since its been working right but i think i recall getting near 2MBs download speeds. I have tried using 3 diffrent usenet service providers and I get the same problem with all(charter limits my connection speed through their NNTP servers.) I have an easynews.com account and they have a web interface to browse their binaries and i get the same issues with that also. I live in a Condo complex with about 100 units and im not sure how the cable company drops their cable to my unit but from what im hearing above it sounds like that might be the problem. Either that or this is Karma coming back to get me ;). I will check out the things you guys mentioned above and hopefully get some answers from charter. Ill let you know what i come up with. Thanks again everyone.
Reply to
Your terminology is a bit confusing because you are saying 1 MBs (1 MegaBytes per second), but the context is of 1 Mbs (1 Megabits per second.
If your download cap speed at Charter is 10 Mbs, then 1 Mbs is pretty bad
It should be up close to 10 Mega bits per second. There is a problem with Charter.
If you're paying for 10, then you should be getting 10.
Charter is the obviously the problem.
Good luck.
Reply to
Robert Heiling
I was using my download speed as it is represented when i download. When downloading from my newsgroup browser it lists it in Mega Bytes/ s . My download speed from charter is 10 Mega Bits/s so my download speed in my newsgroup software is roughly at 8Mb/s peak (although if my speed limiter is off it rarely touches that speed). Looking back i guess saying i WAS getting 2 MB/s was a little over what i could possibly get with a 10Mb/s download from charter. I know it was more than the 1MB/s max im getting now though. Im gonna stop talking now because I am beginning to confuse myself :).
Reply to
We used to call it "shotgunning" when an element is replaced without evidence of failure. In other words, without fully troubleshooting the issue. In this case, I didn't see any indication of a bad modem, but you may get lucky.
You said you already replaced the router, (more shotgunning?), but your issue does remind me that certain older Linksys routers were known to stop passing traffic when subjected to sustained heavy traffic loads. One cause was an improper MTU setting, which I recall could be fixed by manually changing the MTU setting or upgrading the firmware. The other cause that comes to mind was a batch of weak Linksys power supplies.
You also said you replaced your NIC, which was even more shotgunning since you didn't mention whether you checked connectivity during an outage period.
Next time you lose Internet connectivity, see if you can ping your router. If you can, your NIC and Cat5 cable are good. See if you can ping your cable modem. If you can, the Cat5 cable between the router and modem are good, and the LAN side of the cable modem is probably good. See if you can ping your default gateway (get its IP from your router's Admin page). If you can, your modem is good. Alternatively or in addition, ping your assigned DNS servers to help verify connectivity. Check your modem's signal levels during an outage and compare them to the levels you posted above.
Bottom line, attack issues such as this as logically as possible. Resist the urge to replace something unless you have evidence that it's part of the problem. So far, you probably have a perfectly good spare modem, router, NIC, and possibly cables in your parts box.
Reply to
Bill M.
For the most part I was using either parts I already had or parts I wanted but needed an excuse to feel good about buying them. This in my mind justified that urge. As far as this modem my girlfriend is leasing hers and i found a good deal on the D-Link DCM 202 so i told her she could have my Motorola and save some bucks. Thanks for the pinging tips, that all makes sense and I wish I had talked to you a couple months ago about this. After this i guess I better post "How to resist impulse buying" on the psychology groups :).
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