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#55297 by drujaz
Tue May 11, 2010 12:31 pm
Hello All,

I am hoping for some assistance here. I currently have Comcast Cable internet with speed rated at 12Mbps (up) and 3Mbps (down).

Configuration:

Cable Modem -> ooma -> router -> multiple PCs (wired and wireless).

Every few days, my cable modem will go offline with logs stating:

"No Ranging Response received - T3 time-out"

the send signal keeps blinking and the online light shows the modem is offline. Calling Comcast support is useless as all they offer is to disconnect the coax cable and the power, wait 30 seconds, and then reconnect. If that fails, you are SOL and need a new modem.

I am noticing that if I disconnect the ethernet cable, and powercycle the cable modem with the steps above mentioned by Comcast Support, it will come back up and online.

I need to figure out what is causing it to go offline in the first place, and then what is interfering with it coming back online once it goes offline....

Thanks in advance.
#55300 by drujaz
Tue May 11, 2010 12:50 pm
Thanks for that lbmofo, but I have done every reset under the sun, including factory reset on the modem... Based on Comcast's recommendations, I had also replaced the modem and still the same problem occurs. I wouldn't doubt that something's going on on the Comcast side. I decided to go back to DSL since I have never really had any issues with DSL. I am hoping its not an ooma problem that will follow me to the DSL also.

One option was changing my config to connect the ooma behind the router instead of inbetween the modem and the router...
#55301 by lbmofo
Tue May 11, 2010 12:55 pm
That "No ranging response received" was what I was getting too and all I had to do was a factory reset on the modem so it could re-learn my cable line/signal.

Anway, maybe something is wrong with your cable line. Check this out yet?

murphy wrote:Jitter should be less than 5 ms.
Packet loss should be 0.
Download and upload QOS should be at least 70%.
Maximum TCP delay should be under 100 ms.

Try this. Connect to the status web page in your cable modem

http://192.168.100.1

Find the downstream and upstream power in dBmV and the Signal to Noise Ratio (SNR) and report back.

The downstream signal power should be between -10 and +10 dBmV. (Some say between -15 and +15 but I feel that is pushing your luck)

The SNR should be 35 or more.

The upstream power level should be less than 55 dBmV.
#55305 by drujaz
Tue May 11, 2010 1:11 pm
I had tested the line with whichvoip.com's test app quite a few times and all numbers would be within acceptable parameters. The jitter was a bit of concern as it was normally above 4.2 but less then 5.0. QOS was always showing as above 65% (varies with each test).

I can upload the test results when I get home.
#55391 by tommies
Wed May 12, 2010 4:29 pm
I don't thing the
No Ranging Response received - T3 time-out

is the problem, since my modem records up time of 64 days and 15 hrs and no trouble with ooma either. See below for my entire log since I jumped on Comcast offer.

You had said that you have a new cable modem, so it's not the modem. From my experiences, the coaxial cable itself sometime causes lots of trouble. I learned this from the technician who installed the service about 2 months ago.
. the cable has to be grounded properly, it's critical.
. if the cable cracked or moisture got in, it has to be replaced, so the outside connector has to be sealed.
. how far from the tap into the house, what cable is used (it has to be RG-11, it'a a big almost 1/2 in in diameter with bright orange color)


05/12/2010 12.52 68000300 03 DHCP WARNING - Non-critical field invalid in response.
05/12/2010 12.51 82000200 03 No Ranging Response received - T3 time-out
05/12/2010 12.51 84000200 03 SYNC Timing Synchronization failure - Failed to acquire FEC framing
05/12/2010 12.51 84000100 03 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing
05/12/2010 12.48 82000400 03 Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 timeout
05/12/2010 12.17 68000300 03 DHCP WARNING - Non-critical field invalid in response.
05/12/2010 12.17 82000200 03 No Ranging Response received - T3 time-out
05/12/2010 12.17 82000200 03 No Ranging Response received - T3 time-out
05/12/2010 12.17 82000300 03 Init RANGING Critical Ranging Request Retries exhausted
05/12/2010 12.16 82000200 03 No Ranging Response received - T3 time-out
05/12/2010 12.16 82000300 03 Init RANGING Critical Ranging Request Retries exhausted
05/12/2010 12.15 82000400 03 Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 timeout
05/12/2010 08.25 82000500 03 Started Unicast Maintenance Ranging - No Response received - T3 time-out
05/09/2010 02.42 68010300 05 DHCP RENEW WARNING - Field invalid in response
05/07/2010 01.34 68000300 03 DHCP WARNING - Non-critical field invalid in response.
05/04/2010 03.51 68010300 05 DHCP RENEW WARNING - Field invalid in response
04/30/2010 15.51 68010300 05 DHCP RENEW WARNING - Field invalid in response
03/31/2010 01.01 68000300 03 DHCP WARNING - Non-critical field invalid in response.
03/31/2010 01.01 82000200 03 No Ranging Response received - T3 time-out
03/31/2010 01.01 82000300 03 Init RANGING Critical Ranging Request Retries exhausted
03/31/2010 01.01 82000200 03 No Ranging Response received - T3 time-out
03/31/2010 01.00 82000300 03 Init RANGING Critical Ranging Request Retries exhausted
03/31/2010 01.00 82000200 03 No Ranging Response received - T3 time-out
03/30/2010 23.01 82000400 03 Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 timeout
03/29/2010 06.38 68010300 05 DHCP RENEW WARNING - Field invalid in response
03/28/2010 18.30 82000500 03 Started Unicast Maintenance Ranging - No Response received - T3 time-out
03/25/2010 18.38 68010300 05 DHCP RENEW WARNING - Field invalid in response
03/24/2010 18.57 82000500 03 Started Unicast Maintenance Ranging - No Response received - T3 time-out
03/22/2010 06.38 68010300 05 DHCP RENEW WARNING - Field invalid in response
03/21/2010 19.50 82000500 03 Started Unicast Maintenance Ranging - No Response received - T3 time-out
03/18/2010 18.38 68010300 05 DHCP RENEW WARNING - Field invalid in response
03/16/2010 20.55 82000500 03 Started Unicast Maintenance Ranging - No Response received - T3 time-out
#55398 by drujaz
Wed May 12, 2010 7:49 pm
Here are my test results:

VoIP test statistics
--------------------
Jitter: you --> server: 4.4 ms
Jitter: server --> you: 3.6 ms
Packet loss: you --> server: 0.0 %
Packet loss: server --> you: 0.0 %
Packet discards: 0.0 %
Packets out of order: 0.0 %
Estimated MOS score: 4.0

Speed test statistics
---------------------
Download speed: 12322496 bps
Upload speed: 2951264 bps
Download quality of service: 90 %
Upload quality of service: 66 %
Download test type: socket
Upload test type: socket
Maximum TCP delay: 29 ms
Average download pause: 2 ms
Minimum round trip time to server: 30 ms
Average round trip time to server: 35 ms
Estimated download bandwidth: 22400000bps
Route concurrency: 1.8178135
Download TCP forced idle: 34 %
Maximum route speed: 17476000bps

and here is my modem information (MOTOROLA SB5101U):

DOWNSTREAM
Frequency: 723000000 Hz
Signal To Noise Ratio: 34.8 dB
Power Level: -3.8 dBmV

UPSTREAM
Channel ID: 3
Frequency: 30600000 Hz
Power: 43.2 dBmV

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