andyross
join:2003-05-04
Schaumburg, IL
| [Connectivity] Sudden spike in DCC's, Schaumburg IL
Beginning this Sunday, I have been seeing at least 3-4 DCC's (Dynamic Channel Change) a day. We've had D3 since October, and there were a few DCC's while it was being set up. Since Christmas, I only had one or two on one day, but it's been on the same channel otherwise.
I say 'at least' as I have an SB5120, which has a notoriously short log that also logs tons of junk.
I work from home (although I'm on vacation this week), and use both Skype and Vonage. The DCC's cause 10-15 second outages, which can really mess up a phone call, not to mention remote services like Citrix. I don't watch on-line videos or download/upload huge files. Speed-wise, the VPN to work is a T1, so that limits me to 1.5/1.5. Also, these changes are often occurring while everything is shut down.
Just wondering if anyone around here has also seen this. I don't want to buy a D3 modem just to avoid it. |
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andyross
join:2003-05-04
Schaumburg, IL
| This is getting ridiculous:
2009-06-30 08:39:04 4-Error DIST: Management Message with unidentified Version->4 - Discard message
2009-06-30 07:37:57 7-Information Channel Change Complete - Enabling Bridge
2009-06-30 07:37:57 7-Information C203.0 DCC arrive new
2009-06-30 07:37:56 4-Error DIST: Management Message with unidentified Version->4 - Discard message
2009-06-30 07:37:54 3-Critical R02.0 No Ranging Response received - T3 time-out
2009-06-30 07:37:54 4-Error DIST: Management Message with unidentified Version->4 - Discard message
2009-06-30 07:37:54 3-Critical R02.0 No Ranging Response received - T3 time-out
2009-06-30 07:37:54 5-Warning SYNC: US Gain in cache is invalid: 0.00
2009-06-30 07:37:53 7-Information Starting Ranging On Channel 4
2009-06-30 07:37:53 7-Information Downstream Locked - Collecting Upstream Information
2009-06-30 07:37:53 4-Error DIST: Management Message with unidentified Version->4 - Discard message
2009-06-30 07:37:50 7-Information Dynamic Channel Change of Downstream Requested - Disabling Bridge
2009-06-30 07:37:50 7-Information Dynamic Channel Change of Downstream Requested - Setting tuner to 711.0MHz
2009-06-30 07:37:50 7-Information C202.0 DCC depart old
2009-06-30 07:37:49 4-Error DIST: Management Message with unidentified Version->4 - Discard message
2009-06-30 05:55:56 7-Information Channel Change Complete - Enabling Bridge
2009-06-30 05:55:56 7-Information C203.0 DCC arrive new
2009-06-30 05:55:55 4-Error DIST: Management Message with unidentified Version->4 - Discard message
2009-06-30 05:55:53 7-Information Starting Ranging On Channel 3
2009-06-30 05:55:53 7-Information Downstream Locked - Collecting Upstream Information
Event Log has reached maximum size. Older log entries are lost.
Still changing 4 or more times per day, even when everything other than the modem and router is turned off. |
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andyross
join:2003-05-04
Schaumburg, IL
| reply to andyross
Just minutes after the previous post:
2009-06-30 08:42:28 4-Error DIST: Management Message with unidentified Version->4 - Discard message
2009-06-30 08:40:02 7-Information Channel Change Complete - Enabling Bridge
2009-06-30 08:40:02 7-Information C203.0 DCC arrive new
2009-06-30 08:40:00 4-Error DIST: Management Message with unidentified Version->4 - Discard message
2009-06-30 08:39:55 3-Critical R02.0 No Ranging Response received - T3 time-out
2009-06-30 08:39:55 4-Error DIST: Management Message with unidentified Version->4 - Discard message
2009-06-30 08:39:54 3-Critical R02.0 No Ranging Response received - T3 time-out
2009-06-30 08:39:53 4-Error DIST: Management Message with unidentified Version->4 - Discard message
2009-06-30 08:39:53 5-Warning SYNC: US Gain in cache is invalid: 0.00
2009-06-30 08:39:53 7-Information Starting Ranging On Channel 3
2009-06-30 08:39:53 7-Information Downstream Locked - Collecting Upstream Information
2009-06-30 08:39:51 4-Error DIST: Management Message with unidentified Version->4 - Discard message
2009-06-30 08:39:50 7-Information Dynamic Channel Change of Downstream Requested - Disabling Bridge
2009-06-30 08:39:50 7-Information Dynamic Channel Change of Downstream Requested - Setting tuner to 705.0MHz
2009-06-30 08:39:50 7-Information C202.0 DCC depart old
2009-06-30 08:39:49 4-Error DIST: Management Message with unidentified Version->4 - Discard message
2009-06-30 07:37:57 7-Information Channel Change Complete - Enabling Bridge
2009-06-30 07:37:57 7-Information C203.0 DCC arrive new
2009-06-30 07:37:56 4-Error DIST: Management Message with unidentified Version->4 - Discard message
2009-06-30 07:37:54 3-Critical R02.0 No Ranging Response received - T3 time-out
Event Log has reached maximum size. Older log entries are lost. |
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andyross
join:2003-05-04
Schaumburg, IL
| Tried using Citrix for a few minutes, got another change!
2009-06-30 09:41:25 4-Error DIST: Management Message with unidentified Version->4 - Discard message
2009-06-30 09:39:57 7-Information Channel Change Complete - Enabling Bridge
2009-06-30 09:39:57 7-Information C203.0 DCC arrive new
2009-06-30 09:39:57 4-Error DIST: Management Message with unidentified Version->4 - Discard message
2009-06-30 09:39:55 3-Critical R02.0 No Ranging Response received - T3 time-out
2009-06-30 09:39:53 5-Warning SYNC: US Gain in cache is invalid: 0.00
2009-06-30 09:39:53 4-Error DIST: Management Message with unidentified Version->4 - Discard message
2009-06-30 09:39:53 7-Information Starting Ranging On Channel 4
2009-06-30 09:39:52 7-Information Downstream Locked - Collecting Upstream Information
2009-06-30 09:39:51 4-Error DIST: Management Message with unidentified Version->4 - Discard message
2009-06-30 09:39:50 7-Information Dynamic Channel Change of Downstream Requested - Disabling Bridge
2009-06-30 09:39:50 7-Information Dynamic Channel Change of Downstream Requested - Setting tuner to 699.0MHz
2009-06-30 09:39:50 7-Information C202.0 DCC depart old
2009-06-30 09:39:49 4-Error DIST: Management Message with unidentified Version->4 - Discard message
2009-06-30 08:40:02 7-Information Channel Change Complete - Enabling Bridge
2009-06-30 08:40:02 7-Information C203.0 DCC arrive new
2009-06-30 08:40:00 4-Error DIST: Management Message with unidentified Version->4 - Discard message
2009-06-30 08:39:55 3-Critical R02.0 No Ranging Response received - T3 time-out
2009-06-30 08:39:55 4-Error DIST: Management Message with unidentified Version->4 - Discard message
2009-06-30 08:39:54 3-Critical R02.0 No Ranging Response received - T3 time-out
Event Log has reached maximum size. Older log entries are lost.
What the F*** is going on? Is this ever going to be fixed? There is no reason for this. |
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andyross
join:2003-05-04
Schaumburg, IL
| And yet again:
2009-06-30 10:44:01 4-Error DIST: Management Message with unidentified Version->4 - Discard message
2009-06-30 10:35:58 7-Information Channel Change Complete - Enabling Bridge
2009-06-30 10:35:58 7-Information C203.0 DCC arrive new
2009-06-30 10:35:57 4-Error DIST: Management Message with unidentified Version->4 - Discard message
2009-06-30 10:35:54 3-Critical R02.0 No Ranging Response received - T3 time-out
2009-06-30 10:35:54 4-Error DIST: Management Message with unidentified Version->4 - Discard message
2009-06-30 10:35:54 3-Critical R02.0 No Ranging Response received - T3 time-out
2009-06-30 10:35:53 5-Warning SYNC: US Gain in cache is invalid: 0.00
2009-06-30 10:35:53 7-Information Starting Ranging On Channel 3
2009-06-30 10:35:52 7-Information Downstream Locked - Collecting Upstream Information
2009-06-30 10:35:52 4-Error DIST: Management Message with unidentified Version->4 - Discard message
2009-06-30 10:35:50 7-Information Dynamic Channel Change of Downstream Requested - Disabling Bridge
2009-06-30 10:35:50 7-Information Dynamic Channel Change of Downstream Requested - Setting tuner to 693.0MHz
2009-06-30 10:35:50 7-Information C202.0 DCC depart old
2009-06-30 10:35:50 4-Error DIST: Management Message with unidentified Version->4 - Discard message
2009-06-30 09:39:57 7-Information Channel Change Complete - Enabling Bridge
2009-06-30 09:39:57 7-Information C203.0 DCC arrive new
2009-06-30 09:39:57 4-Error DIST: Management Message with unidentified Version->4 - Discard message
2009-06-30 09:39:55 3-Critical R02.0 No Ranging Response received - T3 time-out
2009-06-30 09:39:53 5-Warning SYNC: US Gain in cache is invalid: 0.00
Event Log has reached maximum size. Older log entries are lost. |
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andyross
join:2003-05-04
Schaumburg, IL
| Here's another pair, just 8 minutes apart!
2009-06-30 13:45:36 4-Error DIST: Management Message with unidentified Version->4 - Discard message
2009-06-30 13:41:54 7-Information Channel Change Complete - Enabling Bridge
2009-06-30 13:41:54 7-Information C203.0 DCC arrive new
2009-06-30 13:41:53 4-Error DIST: Management Message with unidentified Version->4 - Discard message
2009-06-30 13:41:52 7-Information Starting Ranging On Channel 4
2009-06-30 13:41:52 7-Information Downstream Locked - Collecting Upstream Information
2009-06-30 13:41:51 4-Error DIST: Management Message with unidentified Version->4 - Discard message
2009-06-30 13:41:50 7-Information Dynamic Channel Change of Downstream Requested - Disabling Bridge
2009-06-30 13:41:50 7-Information Dynamic Channel Change of Downstream Requested - Setting tuner to 705.0MHz
2009-06-30 13:41:50 7-Information C202.0 DCC depart old
2009-06-30 13:41:50 4-Error DIST: Management Message with unidentified Version->4 - Discard message
2009-06-30 13:33:58 7-Information Channel Change Complete - Enabling Bridge
2009-06-30 13:33:58 7-Information C203.0 DCC arrive new
2009-06-30 13:33:56 4-Error DIST: Management Message with unidentified Version->4 - Discard message
2009-06-30 13:33:54 3-Critical R02.0 No Ranging Response received - T3 time-out
2009-06-30 13:33:53 5-Warning SYNC: US Gain in cache is invalid: 0.00
2009-06-30 13:33:53 4-Error DIST: Management Message with unidentified Version->4 - Discard message
2009-06-30 13:33:52 7-Information Starting Ranging On Channel 3
2009-06-30 13:33:52 7-Information Downstream Locked - Collecting Upstream Information
2009-06-30 13:33:51 4-Error DIST: Management Message with unidentified Version->4 - Discard message
Event Log has reached maximum size. Older log entries are lost. |
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andyross
join:2003-05-04
Schaumburg, IL | reply to andyross
Had a brief outage on Wednesday (modem got downlink, but no uplink.) Thought it might fix this, but no. Anytime I use it, I get these f***ing DCC's every 30-40 minutes.
Comcast, we love f***ing our customers. |
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bshelly
Premium
join:2002-02-17
Schaumburg, IL
clubs:
 ·VOIPo
·AT&T CallVantage
| I had the same outage on Wednesday here in Schaumburg and my Moto SB6120 never came back online. It took pulling/plugging the power to get it back. They must have been updating the CMTS' because my powerboost now sucks ass. I only get up to 21mbps down and ~4mbps up. Previously, I would hit 50mbps on the downstream and 10mbps on the upstream temporarily. It sure made my connection feel fast on short downloads 
Comcast, what the heck are you doing? This change negates the point of me having a D3 modem I should just return it to Comcast and go back to my trusty SB5100 and save a few bucks. |
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bshelly
Premium
join:2002-02-17
Schaumburg, IL
clubs:
·VOIPo
·AT&T CallVantage
| reply to andyross
Andyross, since Wednesday night, I only have one entry in my log:
Jul 01 2009 21:27:54 3-Critical R02.0 No Ranging Response received - T3 time-out;CM-MAC=00:21:80:f2:a4:d3;CMTS-MAC=00:01:5c:31:da:01;CM-QOS=1.1;CM-VER=3.0;
I don't know why because I reset the modem to defaults which should show the download of the config file, but it never does. Also, my upstream is now 16QAM where it was 64QAM before
Something seems wrong, bigtime. |
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andyross
join:2003-05-04
Schaumburg, IL
1 edit | I'm on the NE side, near Schaumburg/Plum Grove roads. I had to power-cycle the modem to get it back on-line that one day. The first time it didn't take. I tried again a few minutes later, and it connected, but didn't get the time sync. It took a 3rd try to get it back to normal.
A minute or two after the reconnect, it did a DCC (seemed to confuse the heck out of my VPN, which may have been in the middle of negotiating the connection), but didn't change again for nearly 24 hours. Since then, it's more or less back to constant DCC's. Had one just a few minutes before posting this.
The DCC not only changes the downstream, but may change the upstream. Mine seems to sometimes use 2.56MSym/sec (Channel ID 4@29.6MHz), and other times use 5.12MSym/sec (Channel ID 3@34.4MHz). Downstream moves between 693, 699, 705 and 711MHz.
This is with an SB5120. I've had it for about 3 years. Signal levels are more or less the same on all channels, within 1dB or so.
Edit: Forgot to mention that I also get T3's at times, often while it's negotiating the DCC!! |
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bshelly
Premium
join:2002-02-17
Schaumburg, IL
clubs:
·VOIPo
·AT&T CallVantage
| That's interesting. Come to think of it, I had to power cycle my modem twice as well. I just noticed that my upstream is now at 32QAM and 5.12MSym/sec on Channel 3. When I was on Channel 4, it was only at 2.56MSym/sec. as well.
Comcast is definitely screwing around and needs to get it's act together. It's really irritating me.
I am just west of Roselle Rd. and Weathersfield Way. off of Sienna Dr.
My log is still blank, so I have no idea what is going on |
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FieldHelp
@comcast.com
| reply to andyross
To clear up a few things i thought I would provide you guys/gals some info.
1) the MSym/sec can be directly correlated to channel width. For 3.2mhz wide you would have 2.56MSym/sec. For 6.4mhz wide you would have 5.12MSym/sec.
2) Modulation vs Channel speed.
3.2mhz wide (tdma) 6.4mhz wide (atdma)
16qam 10.24Mbps 20.48Mbps
32qam 12.8Mbps 25.6Mbps
64qam 15.36Mbps 30.72Mbps
3) Why the need for DCC's. Well as you can see above. Different upstream carrier types have different capabilities. There are still a lot of legacy modems in use by customers. For this reason the tdma (3.2mhz) carriers are still alive and kicking. The CMTS manages spikes in utilization of these carriers by using DCC's to move modems to new upstream/downstreams. The problem with this is that not all modems behave as they should when they receive a DCC. Problems can be manufacturer issues with firmware all the way down to local SNR issues. |
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andyross
join:2003-05-04
Schaumburg, IL
| One issue I have when on a 5.12MSym/sec rate is that I occasionally get these on my SB5120:
2009-07-06 14:31:55 5-Warning TSM: TxError WatchDog - Restart Upstream
2009-07-06 14:31:55 5-Warning HAL: Overcoming Tx Error (reseting the US - DMA) |
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FieldHelp
@comcast.com
| reply to andyross
That could indicate an actual issue with your modem when operating in 2.0 modem. It could also be cosmetic. Keep an eye on that error in relation to your service quality.
Here's some info on T3 and T4 timeouts for you guys as well. I believe this will answer the T3 timeout during DCC note as well.
T3
200 msec The time to wait for a RNG-RSP during ranging.
Then the modem gets its chance to "talk" to the CMTS and sends data to negotiate the proper upstream signal levels and timing. This negotiation process takes several data exchanges between the cable modem and the CMTS. If at any point the modem doesn't recieve a response from the CMTS within about 200 milliseconds, a T3 timeout occurs. Several T3s have to occur before a modem resets.
T4
30 sec - The time to wait for a station maintenance interval to perform station maintenance ranging.
Once the modem is online, the CMTS sends "Periodic Ranging" or keep-alive requests to it every 30 seconds. If the modem doesn't recieve one, a T4 timeout occurs. Once 16 of the T4 timeouts have to occured, a modem resets.
If there is a downstream communication problem, the cable modem might not receive these keep-alive requests. If the upstream utilization is too high, or too many modems are connected to the same upstream port, it is possible that some modems will not get the required bandwidth or transmit opportunities to respond to the keep-alive requests. Either of these issues can result in T3 or T4 timeouts occuring. |
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EG
The wings of love
Premium
join:2006-11-18
Union, NJ
1 edit | said by FieldHelp  :Here's some info on T3 and T4 timeouts for you guys as well. I believe this will answer the T3 timeout during DCC note as well. T3 200 msec The time to wait for a RNG-RSP during ranging. Then the modem gets its chance to "talk" to the CMTS and sends data to negotiate the proper upstream signal levels and timing. This negotiation process takes several data exchanges between the cable modem and the CMTS. If at any point the modem doesn't recieve a response from the CMTS within about 200 milliseconds, a T3 timeout occurs. Several T3s have to occur before a modem resets. T4 30 sec - The time to wait for a station maintenance interval to perform station maintenance ranging. Once the modem is online, the CMTS sends "Periodic Ranging" or keep-alive requests to it every 30 seconds. If the modem doesn't recieve one, a T4 timeout occurs. Once 16 of the T4 timeouts have to occured, a modem resets. If there is a downstream communication problem, the cable modem might not receive these keep-alive requests. If the upstream utilization is too high, or too many modems are connected to the same upstream port, it is possible that some modems will not get the required bandwidth or transmit opportunities to respond to the keep-alive requests. Either of these issues can result in T3 or T4 timeouts occuring. Hmm.. Sounds vaguely familiar. Partial C&P from here perhaps ?
»www2.dslreports.com/faq/8560 |
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FieldHelp
join:2009-07-06
North Pole, AK
1 edit | reply to andyross
Actually... that info is shared information between MSO's and the hardware vendors :P
The fact it's printed elsewhere only re-affirms it.
And for the record... the copy I have has a bit more detail including T1 and T2 events. I left that out as we rarely need to discuss them. |
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EG
The wings of love
Premium
join:2006-11-18
Union, NJ
| said by FieldHelp :The fact it's printed elsewhere only re-affirms it. O/k so what came first, the chicken, or the egg ? 
LOL !  |
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andyross
join:2003-05-04
Schaumburg, IL
| reply to andyross
This morning, the modem was connected, and the router was flashing the WAN light, but I had no internet access. I had to reboot the modem to get back on-line. Nothing in the log (wiped by the power cycle and the 5120's short length and hyper-logging). |
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FieldHelp
join:2009-07-06
North Pole, AK | reply to andyross
Time to get your info to ComcastSteve i believe... |
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