Re: [VA] Modem Boot Log Issues in Cox HSI http://www.dslreports.com/forum/r20440494 en Fri, 09 Jan 2009 07:55:52 EDT Fri, 09 Jan 2009 07:55:52 EDT Re: [VA] Modem Boot Log Issues http://www.dslreports.com/forum/remark,20457575 jsimmons : Thanks for the explanation!

Knowledge is our friend. :D

Is it safe to say that (or reasonable to say) that its possible for one US carrier frequency to work better or worse than another due to signal interference or other external influences? If so, I can see that if the DLB causes a dynamic US carrier change, it might affect an individual user's connectivity in undesirable ways. :(

BTW... I see that the time required to effect an upstream channel change is between 2-3 seconds. I assume user data communication is paused during this period?
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"Everything should be made as simple as possible, but not one bit simpler."
- Albert Einstein
]]> http://www.dslreports.com/forum/remark,20457575 Fri, 09 May 2008 14:56:03 EDT Re: [VA] Modem Boot Log Issues http://www.dslreports.com/forum/remark,20450458 CoxNVAHSI : Disclaimer: Each system is different in regard to how many carriers, width of carriers, load balancing of the carriers and potentially in some areas the modulation of those carriers. Disclaimer Done.

In NOVA there are multiple US carriers in each node. How many varies depending on where you are at. What you are seeing is dynamic load balancing. In a pre-DLB world your modem talked on one US. If there were two upstreams, half the modems in a node talked on one and half on the other. If utilization in one particular US was starting to pickup... it would not be addressed until the engineers manually rebalanced the upstreams. Now the system is regularly analyzing load in each upstream and distributing that load accordingly. Automation is your friend. Depending on what is going on you may not see any or like in your case it may happen a couple times a day.

Hope this helps and I am now going to bet on the over/under in how long it is going to take for someone that has been playing COD4 for the past 24 hours straight to tell me that the US channel change created a 2 second lag spike which killed their 36 kill streak and to add insult it was some noob that pwned them ;) Not that I do not think that is important mind you... my 13yr old would be jealous if I had that kind of streak. I am only at 14 but I make up for it with my high k/d ratio. :D]]> http://www.dslreports.com/forum/remark,20450458 Thu, 08 May 2008 09:24:48 EDT Re: [VA] Modem Boot Log Issues http://www.dslreports.com/forum/remark,20449225 jsimmons : I think (Cox Can Confirm) that the upstream channel change is initiated at the CMTS and the modem is instructed (via a downstream command) to switch the upstream to a different frequency. I've seen entries in my modem log where the modem logs a request to initiate channel change.

I also believe that all user modems communicate with the CMTS over the same channel. So a channel change is NOT isolated to your modem only.

Perhaps Cox realized that you and perhaps your neighbors were showing higher error rates on the channel (which in your case may have been causing the repetitive resyncs) so decided to switch to a different channel to clear it up.

I'm doing a little theorizing here, so by all means Cox if what I've said is wrong, please explain how it actually works... Inquiring minds want to know. ;)

EDIT... What a coincidence. In looking at my modem logs tonight, I see numerous upstream channel change requests. See Attached screenshot.
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"Everything should be made as simple as possible, but not one bit simpler."
- Albert Einstein
Click for full size
]]> http://www.dslreports.com/forum/remark,20449225 Wed, 07 May 2008 23:31:42 EDT Re: [VA] Modem Boot Log Issues http://www.dslreports.com/forum/remark,20447682 thebob6 : Yeah my upstream level is at 42 so that is fine. I'm just curious what finally made the upstream channel change because thats what seemed to fix all my problems.]]> http://www.dslreports.com/forum/remark,20447682 Wed, 07 May 2008 18:48:34 EDT Re: [VA] Modem Boot Log Issues http://www.dslreports.com/forum/remark,20447104 jsimmons : Good explanation :D

I have always had great service with upstream levels of 38-40. I can say for sure - once it hits 50, problems are not far away.
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"Everything should be made as simple as possible, but not one bit simpler." - Albert Einstein ]]> http://www.dslreports.com/forum/remark,20447104 Wed, 07 May 2008 16:58:46 EDT Re: [VA] Modem Boot Log Issues http://www.dslreports.com/forum/remark,20447027 CoxNVAHSI : Upstream DOCSIS spec for power is 27 - 54... the sweet spot is 41-48. Anything within 35-52 is fine. The closer you get to the extremes of the DOCSIS spec the more exposure you have in regards to seeing problems. The high end of that range is to ensure that the seasonal drift (temps rise, plant expands resulting in higher transmit)does not put you into a max transmit (55dB on many modems). There are also other design elements that go into it but I would be misrepresenting myself as I am not an RF engineer (I know where they sit though).

So on the upstream your power being low can cause a lot of problems due to being closer to the noise floor. You do not want to be down in the junk. Low Tx is just as bad if not worse (IMHO) than a high Tx. High Tx is a problem but more so when the modem is maxed out (i.e. the CMTS is Kirk and your Cable Modem is Scotty going... "She kinna take any more, Captain. If I give her inny more she'll blow!". Unlike Scotty... your modem knows it's limitations and will not pull a solution out of thin air when asked to tx more than it is designed for.

If you do not get the reference... ask someone that looks older than you to explain.]]> http://www.dslreports.com/forum/remark,20447027 Wed, 07 May 2008 16:45:36 EDT Re: [VA] Modem Boot Log Issues http://www.dslreports.com/forum/remark,20446637 jsimmons :
said by thebob6 See Profile :

I check the modem info page when the tech left and it seems that my upstream channel has indeed changed and so far I've had not had any disco's.
I would hope the upstream power level has decreased a bit (meaning the modem is not having to boost transmit power too much to get a signal to the CMTS). I like to see upstream power at 40 dBmV or below - meaning a good low-loss upstream signal path. Good cables, tight connections, low-loss splitters all contribute to good signal path.
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"Everything should be made as simple as possible, but not one bit simpler." - Albert Einstein ]]> http://www.dslreports.com/forum/remark,20446637 Wed, 07 May 2008 15:41:13 EDT Re: [VA] Modem Boot Log Issues http://www.dslreports.com/forum/remark,20446499 daveinpoway : I have ben unable to locate the post, but, as I recall, the problem would start when the modem was about 2 years old; only some production dates are affected.]]> http://www.dslreports.com/forum/remark,20446499 Wed, 07 May 2008 15:22:12 EDT Re: [VA] Modem Boot Log Issues http://www.dslreports.com/forum/remark,20446383 thebob6 : Hrmph, The tech came out today and replaced the coaxial cable in the house and did verify that the signals seem perfect. Although right before the tech came I was oddly not getting any disconnects. I check the modem info page when the tech left and it seems that my upstream channel has indeed changed and so far I've had not had any disco's.]]> http://www.dslreports.com/forum/remark,20446383 Wed, 07 May 2008 15:01:35 EDT Re: [VA] Modem Boot Log Issues http://www.dslreports.com/forum/remark,20445241 jsimmons :
said by daveinpoway See Profile :

Recently, there was something stated in one of the forums that some SB5120's are constantly rebooting themselves as they get older. No idea if this is your problem or not.
Not sure what the definition of "older" is. I've had mine in continuous operation for about 3 years now (I think) with no such issues. I do have it running on a battery UPS with line conditioning (along with my firewall/router, LAN switch and Access Point).
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"Everything should be made as simple as possible, but not one bit simpler." - Albert Einstein ]]> http://www.dslreports.com/forum/remark,20445241 Wed, 07 May 2008 11:46:53 EDT Re: [VA] Modem Boot Log Issues http://www.dslreports.com/forum/remark,20444082 daveinpoway : Recently, there was something stated in one of the forums that some SB5120's are constantly rebooting themselves as they get older. No idea if this is your problem or not.]]> http://www.dslreports.com/forum/remark,20444082 Wed, 07 May 2008 06:28:00 EDT Re: [VA] Modem Boot Log Issues http://www.dslreports.com/forum/remark,20440969 Irish Shark : Tell the tech ....

"They said again the signal looks perfect and the log shows since 12:01 this morning I have had 54 odd resets. He said it is resetting itself consistently 4 times every hour."
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"You can observe a lot by watching". Yogi Berra]]> http://www.dslreports.com/forum/remark,20440969 Tue, 06 May 2008 16:17:29 EDT Re: [VA] Modem Boot Log Issues http://www.dslreports.com/forum/remark,20440933 thebob6 : If any Cox cable tech do drop by in this thread I would be very happy if you could give me some advise as to what exactly to tell the tech who is coming tomorrow morning.

Thanks]]> http://www.dslreports.com/forum/remark,20440933 Tue, 06 May 2008 16:12:09 EDT Re: [VA] Modem Boot Log Issues http://www.dslreports.com/forum/remark,20440585 thebob6 : Yeah this issue has been going on for a week+ now. I may call Cox again and ask if they can do anything on their side. What should I ask for? Them to change my upstream channel? I really wish some Cox reps would hop in this thread and give some advise.

Edit: Called them. They said again the signal looks perfect and the log shows since 12:01 this morning I have had 54 odd resets. He said it is resetting itself consistently 4 times every hour. He said the only thing he can do is send another tech out. Tech is coming tomorrow morning 8-10. I'm not sure what he is going to do :/]]> http://www.dslreports.com/forum/remark,20440585 Tue, 06 May 2008 15:11:48 EDT Re: [VA] Modem Boot Log Issues http://www.dslreports.com/forum/remark,20440557 jsimmons :
said by thebob6 See Profile :

But Irish have you ever heard of an issue with the Surfboard Sb5120 constantly power cycling itself (once every ~5-10 minutes). The power light stays on but its like someone unplugs the back and plugs in back in real quick. All other lights go off and it goes through the process of reconnecting itself (all lights blinking besides power until they are solid etc). This casues the connection to drop and 2-3 minute 100% packetloss in the process while it tries to reestablish the connection.
This is not a power cycling issue, but sounds more like a loss of sync between the modem and CMTS. I've had that problem periodically. Usually in my case it was an upstream signal issue - plenty of downstream signal and SNR, but the Modem was not seeing a clean upstream path. I reported the issue to Cox, and over time, I saw the upstream channel changed (I assumed from the CMTS side) to find a cleaner frequency. Problem was resolved over the course of a few hours. Apparently there was an area-related issue.
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"Everything should be made as simple as possible, but not one bit simpler." - Albert Einstein ]]> http://www.dslreports.com/forum/remark,20440557 Tue, 06 May 2008 15:07:26 EDT Re: [VA] Modem Boot Log Issues http://www.dslreports.com/forum/remark,20440512 thebob6 : What do you mean by checking/testing? After the first tech came out he was convinced that the signal was too hot thus the video was interfering with the internet and said it was a fairly common problem. Right after he left the issue reoccurred and I called support and the they informed me that that everything looked fine on their side and said they believe the issue to be the modem. It didn't seem like they wanted to send another tech out. What should I ask them to check/test?

Attached another log file, as you can see the connection has dropped again and had to resynch.
Click for full size
]]> http://www.dslreports.com/forum/remark,20440512 Tue, 06 May 2008 14:59:56 EDT Re: [VA] Modem Boot Log Issues http://www.dslreports.com/forum/remark,20440494 jsimmons : My signals have deteriorated a little over the last month. Still well within tolerance, though, as downstream power is -6 dBmV with SNR at 37. Upstream power has increased to 40 when it used to be around 38.

I know these messages are not "bad", as they are only informational or warnings. But past experience has shown that when they do start showing up at a more regular frequency, outages, slowdowns, etc. often follow.
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"Everything should be made as simple as possible, but not one bit simpler." - Albert Einstein ]]> http://www.dslreports.com/forum/remark,20440494 Tue, 06 May 2008 14:57:50 EDT Re: [VA] Modem Boot Log Issues http://www.dslreports.com/forum/remark,20440490 Irish Shark : All that looks fine. It is possible that the MODEM is bad, but I would have Cox do some checking/testing.
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"You can observe a lot by watching". Yogi Berra]]> http://www.dslreports.com/forum/remark,20440490 Tue, 06 May 2008 14:57:22 EDT Re: [VA] Modem Boot Log Issues http://www.dslreports.com/forum/remark,20440465 thebob6 : Here are the signals (this is with a video filter and a brand new splitter that the tech put on). I have also moved tried the connection directly to modem and removed router and the modem still reset itself. I have also tried the modem in a different room with a different coaxial cable from a different outlet( dont know correct term), problem still remained. Here is a updated log file, you will see that it looks the same but all the log entries are updated because the connection already had to reconnect, and there are no critical errors.
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]]> http://www.dslreports.com/forum/remark,20440465 Tue, 06 May 2008 14:52:54 EDT Re: [VA] Modem Boot Log Issues http://www.dslreports.com/forum/remark,20440412 Irish Shark : Have you checked the signals? Are there any other log entries that show "critical" messages?
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"You can observe a lot by watching". Yogi Berra]]> http://www.dslreports.com/forum/remark,20440412 Tue, 06 May 2008 14:44:56 EDT Re: [VA] Modem Boot Log Issues http://www.dslreports.com/forum/remark,20440382 thebob6 : I'm really not trying to thread hijack. But Irish have you ever heard of an issue with the Surfboard Sb5120 constantly power cycling itself (once every ~5-10 minutes). The power light stays on but its like someone unplugs the back and plugs in back in real quick. All other lights go off and it goes through the process of reconnecting itself (all lights blinking besides power until they are solid etc). This casues the connection to drop and 2-3 minute 100% packetloss in the process while it tries to reestablish the connection.]]> http://www.dslreports.com/forum/remark,20440382 Tue, 06 May 2008 14:39:18 EDT Re: [VA] Modem Boot Log Issues http://www.dslreports.com/forum/remark,20440334 Irish Shark : There is no big issues in both of the logs as posted. Most of the entries are information and there are no hard errors in either one.
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"You can observe a lot by watching". Yogi Berra]]> http://www.dslreports.com/forum/remark,20440334 Tue, 06 May 2008 14:33:39 EDT Re: [VA] Modem Boot Log Issues http://www.dslreports.com/forum/remark,20440294 thebob6 : Mind is identical to yours besides one line and I have been having massive problems with my modem resetting itself. Over the phone cox informed me in a time span of 4am to 2pm (10 hours) my modem reset itself 42 times. Motorola is sending me a new modem but Im not convinced that will help my problem. I also had a tech out who said the signal was too strong and put a video filter on the modem. That didnt help either.

Edit: Im in Santa Barbara, Ca, if that makes a difference. Also the Motorola tech said she had never heard of a modem doing what I described.
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]]> http://www.dslreports.com/forum/remark,20440294 Tue, 06 May 2008 14:27:40 EDT [VA] Modem Boot Log Issues http://www.dslreports.com/forum/remark,20440062 jsimmons : Recently I started seeing what appear to be abnormal messages in the modem log. For over a year I've never seen any errors (Including TOD related) in the boot sequence. I'm curious what has changed that causes these priority 5 and 6 messages to now be the norm, rather than the exception? Any ideas, Cox?

A screenshot of the relevant portion of the modem log is attached.
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"Everything should be made as simple as possible, but not one bit simpler."
- Albert Einstein
Click for full size
]]> http://www.dslreports.com/forum/remark,20440062 Tue, 06 May 2008 13:50:04 EDT