Cable internet conection issues

Hydroshock · Post by **Hydroshock** » Tue Sep 26, 2006 6:37 pm

Alright so. I've been having troubles with my connection, i've had 3 of the Adelphia/Comcast techs come to my house and say it's fine so idk what the problem is.

A few times a day i'll get disconnected and my SB5101 modem will have a solid top 2 lights and a flashing 3rd for anywhere from 5min-1hr and it's driving me insane getting disconnected.

The last technician that came by tried to tell me that it could be my router (WRT54G), although I told him i've disconnected it and still gotten the same problems. Then he tried to blame it on the fact that I play online games and that could be disconnecting it and they can't do anything about it, wtf kinda excuse is that, isn't that what they actually include in their advertising that the connection is for?

Anyhow whenever they come they say my signals are fine etc, but when I get disconnected, the error for the 3rd flashing light that seems to repeat itself over and over is ...

2006-09-26 15:51:54 3-Critical T001.0 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing
2006-09-26 15:51:54 3-Critical T002.0 SYNC Timing Synchronization failure - Failed to acquire FEC framing
2006-09-26 15:51:39 3-Critical T001.0 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing
2006-09-26 15:51:38 3-Critical T002.0 SYNC Timing Synchronization failure - Failed to acquire FEC framing

but i've also had these errors either before or after those blocks

1970-01-01 00:00:09 3-Critical D003.0 DHCP WARNING - Non-critical field invalid in response.
2006-09-26 15:51:07 3-Critical R004.0 Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 timeout
1970-01-01 00:00:12 3-Critical R005.0 Started Unicast Maintenance Ranging - No Response received - T3 time-out

Any help would be appreciated.

Hydroshock · Post by **Hydroshock** » Wed Sep 27, 2006 7:06 pm

From what i've read my upstream signal was too strong, on the borderline of the range and i'm thinking that the intermittent problems were from it going above that signal range. I've connected an extra splitter between the line and the modem to see if that will keep it steady.

But what do I know? Here's my modem snapshot signals after adding that extra splitter.

Downstream Value
Frequency 663000000 Hz Locked
Signal to Noise Ratio 37 dB
Power Level 3 dBmV

Upstream Value
Channel ID 3
Frequency 32000000 Hz Ranged
Power Level 55 dBmV

Hydroshock · Post by **Hydroshock** » Thu Sep 28, 2006 2:10 am

Okay so that idea didn't really work. I was reading around and found http://www.speedguide.net/read_articles.php?id=124 on the site, that seems to be about the same problem.

The thing is one tech that came actually mentioned that sorta thing bu said since the problem has such a small margin, if he filled out the paperwork it would probably still get turned down to be changed. So uh... any ideas what I could do? I spose if I couldn't get their attention I could just break the law and physically break the thing so they HAVE to fix it >.> but i'm sure that's the last thing anyone would wanna do.

trogers · Post by **trogers** » Thu Sep 28, 2006 2:27 am

Hydroshock wrote: From what i've read my upstream signal was too strong, on the borderline of the range and i'm thinking that the intermittent problems were from it going above that signal range.

Upstream Value
Channel ID 3
Frequency 32000000 Hz Ranged
Power Level 55 dBmV

If I am not wrong, upload streams have to originate from your comp through your modem and out. Tinkering the ISP box to your modem and adding an extra splitter address the wrong side of the problem.

Do this network diagnostic test and see if it can highlight the problem:

http://nitro.ucsc.edu/

Hydroshock · Post by **Hydroshock** » Thu Sep 28, 2006 10:41 pm

well i was told by the tech that it's unable to sync with the upstream or whatever.

I've managed to get the modem to reconnect sometimes by swapping the splitter in and out (sounds weird for it to fix it sometimes by connecting it)

Hydroshock · Post by **Hydroshock** » Sat Sep 30, 2006 4:18 pm

Alarm: Duplex mismatch condition exists: Host set to Full and Switch set to Half duplex

That is coming up with the test. I can't figure out how to change the settings.
Although the modem i'm using once again is Sb5101 and router is WRT54G (v4)

Hydroshock · Post by **Hydroshock** » Sat Sep 30, 2006 5:24 pm

mistake, I have an SB5100

trogers · Post by **trogers** » Sun Oct 01, 2006 2:17 am

[quote="Hydroshock"]
Alarm: Duplex mismatch condition exists: Host set to Full and Switch set to Half duplex
&#8203]

Go to Control Panel=>System=>Device Manager=>Hardware=>Network Adapter

Click right on it and go to Properties.

Under Speed & Duplex, set it to either autosensing or 10 Mbps Full Duplex.

undersc0re · Post by **undersc0re** » Mon Oct 02, 2006 5:44 am

You should make sure that no one has added any splitters to your cable in your house, and make sure no one has added any devices at the ends of your cable in your household, these changes can cause some intermittent problems. Also tighten up any connections in the Rg6 or whatever cable is used.

Hydroshock · Post by **Hydroshock** » Wed Oct 04, 2006 2:42 pm

undersc0re wrote:You should make sure that no one has added any splitters to your cable in your house, and make sure no one has added any devices at the ends of your cable in your household, these changes can cause some intermittent problems. Also tighten up any connections in the Rg6 or whatever cable is used.

There's been no added splitters besides from the cable guy who has checked the connections. I had another tech come back again yesterday that couldn't find any problems with anything, he checked all the connections in the house.

Also I'm wondering if anyone could explain how a duplex mismatch could kick the modem offline and not come back online.

trogers · Post by **trogers** » Wed Oct 04, 2006 2:56 pm

Here is a good link about duplex mismatch:

http://www.cites.uiuc.edu/network/autos ... nsequences

Hydroshock · Post by **Hydroshock** » Wed Oct 18, 2006 6:51 pm

Well that Duplex Mismatch stuff wasn't the problem, it's still doing it, but now it appears a friend of mine that lives up the street (thought across a main street so idk if he's ont he same amp) is having similar problems, he has a Linksys modem

1970-01-01 00:13:35 critical SYNC Timing Synchronization failure - Failed to receive MAC SYNC frame within time-out period
1970-01-01 00:13:13 critical No Ranging Response received - T3 time-out
1970-01-01 00:12:52 critical No UCD's Received - Timeout

repeating those.

Although his signals are

Lock Status Operational
Modulation 256QAM
Channel ID 1
Provisioned Rate 4823 kbps
Symbol Rate 5360.537 Ksym/sec
Downstream Power -1.4 dBmV
SNR 28.1 dB

Upstream Channel

Lock Status Operational
Modulation 16QAM
Channel ID 3
Provisioned Rate 463 kbps
Symbol Rate 2560 Ksym/sec
Upstream Power 55.3 dBmV

-------------------------

Now I've managed to get to my modem logs while it's disconnecting and I had signal strenghs such as

Downstream Power 13
SNR 37

Upstream Channel

Channel ID 2
Upstream Power 8 dBmV

So it's definitely the upstream breaking with a power level that low.

travis2144 · Post by **travis2144** » Wed Oct 18, 2006 8:13 pm

yeah something is def. changin, 28 is a bad s/n ratio then you say you get a 37 which is super and you gain like 15db, something is funky. tell then next tech out what you are seeing, just be polite about it.

Mad_Haggis · Post by **Mad_Haggis** » Fri Oct 20, 2006 1:30 am

travis2144 wrote:yeah something is def. changin, 28 is a bad s/n ratio then you say you get a 37 which is super and you gain like 15db, something is funky. tell then next tech out what you are seeing, just be polite about it.

AVG S U C K S ! ! !

?/ ? ?// ???

travis2144 · Post by **travis2144** » Mon Oct 23, 2006 2:45 pm

Mad_Haggis wrote:AVG S U C K S ! ! !

?/ ? ?// ???

what's that supposed to mean?

Hydroshock · Post by **Hydroshock** » Wed Oct 25, 2006 1:10 pm

Okay well i've found a new solution maybe to my problem

A tech had gone to my friend's house yesterday, he was having a pretty similar problem, although his was caused by a bad splitter hidden on the line from the old days.

I explained to him my problem, it appears I was correct about the upstream dBmV being just on the edge, but he says that the amp they put on my line etc. was probably a forward amp (it was), he also said that a reverse amp would probably fix my problem all together (makes sense, it's been cold lately and I haven't been disconnected now that my upstream shows Power Level 53 dBmV). From what I understand making the signal stronger on that line the dBmV gets smaller.

Sava700 · Post by **Sava700** » Thu Oct 26, 2006 12:40 am

Been alot of Comcast upgrades to the Adelphia network here lately..so it might not be all you. Plus you say your 3rd light is just blinking for ever and a day...which ever is taking the longest to sync up seems to be where your problem lies as in power rating or DB. Look at your outside box where the line comes into the house and just make sure its clean unhook it and hook it back up..sometimes that makes a difference...otherwise any splitters in the line can do harm along with issues at the pole with the nod or amp.

suddenlink · Post by **suddenlink** » Sun Nov 05, 2006 10:32 am

Looks like your upstream power is a little high, 55 is border line. This number is gonna vary with the temp change by a few db, the hotter it is outside the higher that particular number will get causing you to loose conn. Also splitter config and cable lenght has a big role. Are you off the first split? If you are and you cable lines are fairly new I would believe it to be a balancing issue on the main line (not enough signal getting to your house). I dont like to see that number get above 52.

ScorpioPhoenix64 · Post by **ScorpioPhoenix64** » Sat Nov 25, 2006 8:26 am

Cable modems weren't like the TCP/IP physical wire troubleshooting I do with Cisco and Microsoft base technologies. This new territory was confusing and a whole different thing, like starting over. I bought a Motorola wireless Gateway SGB900 to replace an aging modem which I use for Comcast. After three days of working well, I pooched the configuration playing around and did a total reset. One day later, I started getting transmit\receive logs filled with CRITICAL timing errors including the subject line. DHCP errors should have been my first clue. I was thinking "it's the modem". Well, having solved the problem, it wasn't. The DHCP error and all of the timing sync errors were from the wireless unit trying to get my 5.8Ghz phone online as a client. Comcast intrution detection hardware will drop even strong connections if the behavior seems to be "flooding" or "overflow" related. I turned the wireless component off as a troubleshoot and sure enough,not one single Critical error. I turned it back on, turned the phone off and I got two within 24 hours. Which tells me that someone in the apartment complex has a wireless device that a)the signal is too weak and causing the problem or b)they have a 2.4 or like mine, 5.8 Ghz phone "wanting to surf the Net".
Before taking the modem back (which made no real sense) I did some elimination process troubleshooting. I have since realized that locking down the CSID broadcast to 'off' and coding only my MAC addresses as able to connect to the wireless, there is peace in the world. You must do this every time you pooch the modem though and reseting encryption keys can be a pain in the @!#$ over and over.
Also, if you're getting these errors and DON'T have wireless then, it's obvious your getting signal crosstalk from another LAN device due to proximity or power outlet EMI. The bottom line is IF you're getting great stats on the cable summary with strong connections, it can be a portion of your device other than the modular demulator, however, it's something outside of the modem interfering inward.
I thought 5.8 would make me safe until I read about signal harmonic multiple echos. A 5.8 is 2.4 x 2, which means like RAM in a computer, there is a direct relationship in the quantities. 5.8 can mirror echo on 2.4 wavelengths.

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Cable internet conection issues

Cable internet conection issues

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