russellgds
join:2006-04-21
Addison, TX
|  [Connectivity] Nightmare with intermittent disconnects
My modem re-initializes and reconnects to Comcast several times per hour. When this happens, the bottom three green lights go out (Receive, Send, and Online, but not Power, which stays on), then come back on flashing one at a time until they're all steady again and I'm back online. This happens any time of day or night, whether I'm using the computer or not, and even when the computer isn't connected to the modem. This has been happening since I first got Comcast service three weeks ago here in Addison, Texas.
I've tried three different modems so far, one was the modem I own and the other two were from Comcast. The modem I own is a Motorola SB5100, and the log file is filled with errors such as this, which are logged whenever the problem happens:
Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 timeout
Started Unicast Maintenance Ranging - No Response received - T3 time-out I've had four Comcast techs come out to my apartment so far. Every cable ending in my apartment has been changed. Twice. Including the ones in the patch panel room down the hall, where it comes into my floor. The techs report that the signal strengths are good, which I can confirm as well:
Downstream:
Frequency: 615000000 Hz Locked
Signal to Noise Ratio: 35 dB
Power Level: -6 dBmV
Upstream:
Channel ID: 2
Frequency: 19500000 Hz Ranged
Power Level: 44 dBmV
One of the techs ran a long cable from the patch panel room where it comes into my floor, down the hall directly to my modem, but it still happened.
I've tried switching computers (both XP Pro), and I use a straight connection from the wall to the modem to the PC, with no router or other equipment connected. On one machine the only firewall running was the Windows firewall.
The problem has been escalated to a line crew for a "line probe", but they closed the ticket without finding a problem (or contacting me).
I can make the problem happen more often by running a program that transfers a decent amount of data. One of the easiest programs to cause it with is Skype, the VOIP program. But even that program averages about 90 Kbps up and down, which isn't even near my limit of 8Mb/768Kb.
Last night I disconnected the modem from the PC, so it was only connected to power and to the cable from the wall. This morning the modem log reported another T3 timeout error. I'm assuming it disconnected again even with no computer connected to it.
I also have digital cable TV and digital phone service from Comcast. When the internet problem happens, neither the TV nor phone services are affected. However, I'm unable to use Video On Demand and have been told by three techs that the entire apartment complex is unable to use it because of some kind of upstream problem with the fiber optic lines here. The TV works well on the digital channels, but all channels below 120 are analog and are very low quality. I've been told this is complex-wide as well.
I found this web page discussing the T3 and T4 timeout issues -- this is for Cisco cable equipment, and I'm wondering if it might apply to my situation with Comcast. But I have no idea how to get an expert at Comcast to look into the problem.
Cable Modems Dropping Offline in a 2-way Cable Network
»www.cisco.com/warp/public/109/cm···ine.html
3 weeks and 4 techs have come and gone and I'm no closer to a solution. I've made countless phone calls to support, and have received broken promises by several supervisors.
I'd appreciate any advice or suggestions -- thanks!
Russell |
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Johkal
Cool Cat
Premium,MVM
join:2002-11-13
Happy Valley
clubs:
 ·Comcast Digital Vo..
 ·Comcast
·Vonage
1 edit | With everything you described, there is nothing on your end you can do.
If you feel that your issue is not being addressed properly, you can call the Executive Complaint Center.
»/faq/comcast/2···ng#11091
They are listed as:
Comcast Cellular Communications
1500 Market St
Philadelphia, PA 19102-2100
(215) 665-1700
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|
turkchgo
join:2002-01-13
Skokie, IL
| reply to russellgds
> One of the easiest programs to cause it with is Skype, the VOIP program.
I'm having similar issues, however they go away when I *don't* run my VOIP program.
I can't be 100% sure, but with all the messages on here about connectivity problems this week, I'd be willing to bet all of them are running VOIP programs that are not the one Comcast sells.
There was just an article online about different ISP's doing this. |
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rody_44
Premium
join:2004-02-20
Quakertown, PA
·Comcast
| reply to russellgds
the forum is actually pretty quiet when you consider how many subs comcast has. as far as the problem it seems its most likely a line issue. ide call corporate and demand that it be fixed. i can also be sure it has nothing to do with the fact you use skype. |
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ecko4o8
join:2003-12-08
San Jose, CA
| i've been having the same problem 
i cant play guild wars because it would log me off or something and my modem would reconnect  |
|
Johkal
Cool Cat
Premium,MVM
join:2002-11-13
Happy Valley
clubs:
·Comcast Digital Vo..
·Comcast
·Vonage
| For better assistance, start a new thread.
Review this: »Comcast High Speed Internet FAQ »How To Get Help!
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|
turkchgo
join:2002-01-13
Skokie, IL
| reply to rody_44
> i can also be sure it has nothing to do with the fact you use skype
Alright, I'll take that back. Based on some testing I did today, SIPPhone (and Skype too) seemed to be the culprits. It appears to just be a bizarre coincidence now.
The problem continues tonight and I'm not running any VOIP. I have terrible packet loss and unplugging the modem results in a 30 minute reboot process. It takes forever to finally sync.
Here's a posting of the modem logs while it was trying to sync up and what the status and config pages said about the modem:
Software Version: SB5120-2.14.0.7-SCM00-NOSH
Hardware Version: 4
MIB Version: II
GUI Version: 1.0
VxWorks Version: 5.4
Downstream:
Frequency 711000000 Hz
Signal to Noise Ratio 33 dB
QAM 256
Network Access Control Object OFF
Power Level 0 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
Channel ID 3
Frequency 23984000 Hz
Ranging Service ID 34
Symbol Rate 2.560 Msym/s
Power Level 33 dBmV
Time Priority Code Message
700101000335 7-Information 7 T500.0 Acquired Upstream .......... SUCCESS
700101000335 7-Information Trying to register through CMTS...
700101000335 7-Information SYNCHRONIZED - 711000000 Hz , ucd 3
700101000333 7-Information Starting Ranging On Channel 3
700101000332 3-Critical R02.0 No Ranging Response received - T3 time-out
700101000331 3-Critical R02.0 No Ranging Response received - T3 time-out
700101000330 5-Warning SYNC: US Gain wasn't found in cache
700101000328 7-Information Starting Ranging On Channel 2
700101000324 7-Information Downstream Locked - Collecting Upstream Information
700101000324 7-Information 7 T501.0 Acquired Downstream (711000000 Hz)........ SUCCESS
700101000322 7-Information Scanning frequency 711000000Hz
700101000321 7-Information Scanning frequency 705000000Hz
700101000321 7-Information Scanning frequency 699000000Hz
700101000321 3-Critical T01.0 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing
700101000320 7-Information Scanning frequency 693000000Hz
700101000320 3-Critical T04.0 SYNC Timing Synchronization failure - Failed to receive MAC SYNC frame within time-out period
700101000319 7-Information Scanning frequency 687000000Hz
700101000319 3-Critical T01.0 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing
700101000319 7-Information Scanning frequency 681000000Hz
700101000319 3-Critical T04.0 SYNC Timing Synchronization failure - Failed to receive MAC SYNC frame within time-out period
700101000318 7-Information Scanning frequency 675000000Hz
700101000318 3-Critical T04.0 SYNC Timing Synchronization failure - Failed to receive MAC SYNC frame within time-out period
700101000317 7-Information Scanning frequency 669000000Hz
700101000317 3-Critical T04.0 SYNC Timing Synchronization failure - Failed to receive MAC SYNC frame within time-out period
700101000316 7-Information Scanning frequency 663000000Hz
700101000316 3-Critical T04.0 SYNC Timing Synchronization failure - Failed to receive MAC SYNC frame within time-out period
700101000315 7-Information Scanning frequency 657000000Hz
700101000314 7-Information Scanning frequency 651000000Hz
700101000314 3-Critical T01.0 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing
700101000314 7-Information Scanning frequency 645000000Hz
700101000314 3-Critical T04.0 SYNC Timing Synchronization failure - Failed to receive MAC SYNC frame within time-out period
700101000313 7-Information Scanning frequency 639000000Hz
700101000312 7-Information Scanning frequency 633000000Hz
700101000312 7-Information Scanning frequency 627000000Hz
700101000311 7-Information Scanning frequency 621000000Hz
700101000311 7-Information Scanning frequency 615000000Hz
700101000310 7-Information Scanning frequency 609000000Hz
700101000310 7-Information Scanning frequency 603000000Hz
700101000309 7-Information Scanning frequency 597000000Hz
700101000309 7-Information Scanning frequency 591000000Hz
700101000308 7-Information Scanning frequency 585000000Hz
700101000308 7-Information Scanning frequency 579000000Hz
700101000307 7-Information Scanning frequency 573000000Hz
700101000307 7-Information Scanning frequency 567000000Hz
700101000307 7-Information Scanning frequency 561000000Hz
700101000306 7-Information Scanning frequency 555000000Hz
700101000306 7-Information Scanning frequency 549000000Hz
700101000305 7-Information Scanning frequency 543000000Hz
700101000305 7-Information Scanning frequency 537000000Hz
700101000305 7-Information Scanning frequency 531000000Hz
700101000305 7-Information Scanning frequency 525000000Hz
700101000305 7-Information Scanning frequency 519000000Hz
700101000305 3-Critical T04.0 SYNC Timing Synchronization failure - Failed to receive MAC SYNC frame within time-out period
700101000305 4-Error SYNC: Hardware didn't detect SYNC msg for 600ms during Initial Ranging
700101000304 7-Information Scanning frequency 513000000Hz
700101000304 7-Information Scanning frequency 507000000Hz
700101000304 3-Critical T01.0 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing
700101000304 7-Information Scanning frequency 501000000Hz
700101000304 3-Critical U02.0 UCD invalid or channel unusable
700101000304 7-Information Scanning Upstream 3 (mode 8) in Current Downstream frequency 711000000Hz
700101000304 7-Information Trying to synchronize ...
700101000304 5-Warning DHCP - FAILED
700101000304 3-Critical D01.0 DHCP FAILED - Discover sent, no offer received
700101000304 5-Warning DHCP: (DISCOVER) waitChkReXmitMsg FAILED
700101000206 7-Information 7 T500.0 Acquired Upstream .......... SUCCESS
700101000206 7-Information Trying to register through CMTS...
700101000206 7-Information SYNCHRONIZED - 711000000 Hz , ucd 3
700101000203 7-Information Starting Ranging On Channel 3
700101000202 3-Critical R02.0 No Ranging Response received - T3 time-out
700101000201 3-Critical R02.0 No Ranging Response received - T3 time-out
700101000200 5-Warning SYNC: US Gain wasn't found in cache
700101000159 7-Information Starting Ranging On Channel 1
700101000159 3-Critical R03.0 Ranging Request Retries exhausted
700101000155 3-Critical R02.0 No Ranging Response received - T3 time-out
700101000150 3-Critical R02.0 No Ranging Response received - T3 time-out
700101000149 3-Critical R02.0 No Ranging Response received - T3 time-out
700101000145 3-Critical R02.0 No Ranging Response received - T3 time-out
700101000142 3-Critical R02.0 No Ranging Response received - T3 time-out
700101000140 3-Critical R02.0 No Ranging Response received - T3 time-out
700101000137 3-Critical R02.0 No Ranging Response received - T3 time-out
700101000133 3-Critical R02.0 No Ranging Response received - T3 time-out
700101000132 3-Critical R02.0 No Ranging Response received - T3 time-out
700101000130 3-Critical R02.0 No Ranging Response received - T3 time-out
700101000128 3-Critical R02.0 No Ranging Response received - T3 time-out
700101000124 3-Critical R02.0 No Ranging Response received - T3 time-out
700101000121 3-Critical R02.0 No Ranging Response received - T3 time-out
700101000119 3-Critical R02.0 No Ranging Response received - T3 time-out
700101000116 3-Critical R02.0 No Ranging Response received - T3 time-out
700101000115 3-Critical R02.0 No Ranging Response received - T3 time-out
700101000114 5-Warning SYNC: US Gain wasn't found in cache
700101000113 7-Information Starting Ranging On Channel 6
700101000113 7-Information Scanning Upstream 3 (mode 8) in Current Downstream frequency 711000000Hz
700101000113 7-Information Trying to synchronize ...
700101000113 5-Warning DHCP - FAILED
700101000113 3-Critical D01.0 DHCP FAILED - Discover sent, no offer received
700101000113 5-Warning DHCP: (DISCOVER) waitChkReXmitMsg FAILED
700101000009 7-Information 7 T500.0 Acquired Upstream .......... SUCCESS
700101000009 7-Information Trying to register through CMTS...
700101000009 7-Information SYNCHRONIZED - 711000000 Hz , ucd 3
700101000008 7-Information Starting Ranging On Channel 3 |
|
Johkal
Cool Cat
Premium,MVM
join:2002-11-13
Happy Valley
clubs:
·Comcast Digital Vo..
·Comcast
·Vonage
| From your log:
Your modem is sending a request to register again & again; meaning that either there is a problem at the CMTS or possibly a modem hardware issue.
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Write me up a 125.......I Can't Drive 55 »redrocker.com/ »cabowabo.com/ |
|
turkchgo
join:2002-01-13
Skokie, IL
| Well, well, well, amazingly enough Comcast High Speed Internet suffered an outage in my area Saturday from 11:00 a.m. to 6:00 p.m. and when it came back online, all previous problems went away and have been working fine for the last 24 hours. Including running 3rd party VOIP software. 
Guess there *was* something wrong on their end and they fixed it.  |
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