intermittent cable modem resets caused by signal drop

Interesting conversation... I have a SB6120 and I see the same problem with another service provider.  Lately, so bad, that I struggle to maintain a connection for any length of time. From what I can see, my stats are fine, so I can already predict the answer I'll get.

I am struggling with a similar issue here in north Phoenix. Here is the email thread between me and Cox "Tech Support":

******************

CustomerInquiry: I have been getting cable modem resets most every
day since the beginning of July.

From my SB 6121 Log:

TLV-11 - unrecognized OID;CM-MAC=a4:7a:a4:b7:c0:63;CMTS-MAC=00:1b:54:c9:b5:64;CM-QOS=1.1;CM-VER=3.0;

No Ranging Response received - T3 time-out;CM-MAC=a4:7a:a4:b7:c0:63;CMTS-MAC=00:1b:54:c9:b5:64;CM-QOS=1.1;
CM-VER=3.0;

Unicast Ranging Received Abort Response - initializing MAC;CM-MAC=a4:7a:a4:b7:c0:63 CMTS-MAC=00:1b:54:c9:b5:64;CM-QOS=1.1;CM-VER=3.0;

My signal levels are good and have not changed.

Please have tech support look at the CMTS Flap List and check to see if other cable modems in my neighborhood are also experiencing problems.

Thank you,

****** From Cox Support ******:

Dear _____,

Thank you for your e-mail. I understand you are still having
difficulties with the service. I apologize for any inconvenience this
may caused you. In this case I recommend schedule a technical visit for
you. The closest technician available is on 07/30/12 between 8:00 am -
10:00 am and also between 3:00 pm - 5:00 pm. These times are subject to
change, so please contact us as soon as possible to confirm the date and
time you are interested in. In case the previous dates and times do not
apply, please reply to this e-mail message as soon as possible with a
date and time that is convenient for you and we will try to arrange a
technician in the closest time slot possible. Please be aware of the
following:

1. There must be a person 18 years of age or older present at the time of the visit in order for the technician to enter the
residence.

2. The technician should call approximately 45 minutes prior to the appointment for confirmation purposes.

3. Please remember that all equipment must be in an accessible location and pets should be kept
at a distance from the technician.

4. If the problem is originated by Cox, there will be no charge or additional fee for the visit.

5. If the problem result to be in your end or with your equipment you will be charged with a fee for the visit.

Please provide the information requested above at your earliest convenience to have this request fulfilled as soon as possible. Thank you for choosing Cox as your friend in the digital age. Sincerely, STP - Josh R.

*************************

CustomerInquiry:
 I indicated that I would like Cox Tech Support to "Please have tech support look at the CMTS Flap List and check to see if
other cable modems in my neighborhood are also experiencing problems."

Instead I got the predictable non response from a non technical Cox support person wanting to send out a service tech (possibly at my expense if the Cox equipment is not at fault).

This is an intermittent problem and the only way I can prove the problem is not mine is to purchase a replacement cable modem which I don't believe I should have to do since I think the problem is likely a Cox problem.

Therefore, I will give Cox 30 days to look into this issue without my assistance. If the problem is not corrected, I will probably discontinue all service with Cox and have CenturyLink come in for less money and hopefully
improved customer service!

****** From Cox Support ******:

Dear _________r:

Thank you for your e-mail. I understand you are having network latency
difficulties with your Internet service. I am happy to assist you on
this matter and sincerely apologize for any inconvenience this
difficulty could have caused you.

I have checked your modem signals and it is working properly. Here are a
few suggestions to help troubleshoot slow speed difficulties with your
Cox High Speed Internet service.

First, restart your computer and then clear the cache in the browser.
When you have corrupted files or large number of files in your cache,
Web pages may hang or not fully load. Browser programs will
automatically regenerate these files as required. Performance will be
increased if you disable the use of proxy servers, as none are used on
the Cox network.

A. I will suggest you delete your Internet browser cookies and temporary
files. To clear the cookies in Internet Explorer, please do the
following:

1. Open Internet Explorer.

2. Click [Tools], then click [Internet Options].

3. Under "Temporary Internet files", click [Delete Cookies...]. The
Delete cookies window will appear, Click [OK].

4. On the Internet Options window, Click [OK].

B. After performing the above procedure, please reset the cable modem by
following these steps:

1. Turn off your computer.

2. Turn off the cable modem.

3. Wait 30 seconds.

4. Turn on the cable modem.

5. Turn on the computer.

If you use a router or hub, please bypass it and connect your computer
directly to the cable modem before performing the steps above. A router
acts as a firewall, which could block packets of information from your
cable modem to the computer if not configured properly. The same applies
for wireless connections, which are more susceptible to poor signal
difficulties.

If after following these guidelines you continue to experience
difficulties, do not hesitate to contact us with more clarification on
this difficulty. Please take a moment to answer the following questions:

1. Are you using a firewall or other type of security software?

2. Did you install anything or perform any system configuration changes
prior to this situation?

3. Are you having other symptoms such as error messages, pop-ups or
warnings? If so, please provide us with the text of these messages.

4. Do you experience slowness at all times when using the computer or
only when browsing the Internet?

Please provide answers to these questions in order to reply with a more
accurate solution to the difficulty you are experiencing.

**********************

I am done communicating with idiots. Network Latency?

NO....THE PROBLEM IS THE CABLE MODEM RESETTING DUE TO HANDSHAKING ISSUES WITH THE COX CMTS.

The log files on my SB6121 cable modem clearly show this.

Please send this up to the top level tech support team who understand these networking concept like "CMTS Flap List" .

I repeat.... Either Cox will put the right tech support on this issue or I will change to CenturyLink. Hopefully they don't load down their tech support with poorly trained, non technical, canned response monkeys.

......... CenturyLink is looking better all the time!

Having the same issue as Jlm1228 since some time in June. Occurs at my place in Tempe and also at parents' place in Goodyear. Very annoying.

I am confident that there are many Cox customers experiencing this common issue. Many of those customers are probably unaware of the issue if they mostly use the internet for email and web surfing. They may experience a pause in service now and then but no big deal. Others like those of us who are tech savvy and are looking for answers are frustrated by the Cox Support Firewall. We need a knowledgeable advocate within Cox who can push this to the top of the Cox food chain.

I use the internet for important, real time uses, and when I have a modem disconnect it is more than an annoyance!

I've been experiencing a similar problem for roughly 6 weeks. I'm in Bethany, OK.

The signal from Cox drops 10-30 times daily for as much as 2 or 3 minutes at a time. My wife and I work from home, she does marketing and promotions and I do I.T. support. I've had a Cox internet connection since it was first available in my area and the customer service, while bad initially, has steadily gotten worse over the years. This may be my impetus to put in a grown-up network connection in.

I would wait on that Cisco modem. My research says this is a Cox issue and not a Motorola issue. Hopefully enough of us  pinging the Customer Support Firewall (non-technical script monkeys), will finally get the attention of some real Cox technical talent (I have to believe they are in there somewhere).

I'm also having the same problem of intermittent rebooting/connection dropping in north Phoenix with the SB6120 modem.  The issue has been going on for about 2 months.  All the modem levels are within spec.  I've called tech support and of course all they can tell me is "everything looks fine."  The first tech insisted it was my router and that maybe a neighbor was using my connection and using up bandwidth causing the drop.  I explained that my router is hard wired with no wireless capability, so that was not possible.  He said he never heard of such a router and insisted it was the issue and that I should check the wireless security settings.  The conversation got a bit heated at that point and he put me on hold.  He returned and apologized and said he checked online and "educated himself" regarding the router.  Unbelievable.

 So, I'm in the same boat with the rest of you.  I don't think I should have to spend $90 for the Cisco modem from Cox.  They need to fix the issue on their end or supply a Cisco modem free of charge.  I just sent tCox another email stating such for what little good it will do.

For those of you technically inclined; Here is a very informative document from Cisco: "Cable Modems Dropping Offline in a 2-way Cable Network" 

http://www.cisco.com/en/US/tech/tk86/tk89/technologies_tech_note09186a0080094bb1.shtml

Maybe someone at Cox could take a look at this too!

It is apparent to me that there are many sources of potential upstream interference on these cable systems. A good cable operator must send QUALIFIED network technicians out into the field and be ever diligent in diagnosing and solving these network problems. NOT JUST SENDING "TECHS" TO THE CUSTOMER HOMES LOOKING FOR CUSTOMER CAUSED PROBLEMS.

Bought a Zoom5341J, same issues if not a little worse.  So unless it uses the same chipset as the Motorola modems, no help there.   A previous post mentioned that this might be inherent with DOCSIS 3.0, although I used this modem for years, maybe Cox introduced some new logic or software to "better use" DOCSIS 3.0 and this is the result.

I may try the Motorola 5100series modem next with is DOCSIS 2.0, I think it will still be superior to switching to DSL.

I believe there is a larger systemic problem with the cable system. Cox has been adding more and more digital services to the network. I just added the new Cisco whole house set top boxes here at my house. These new boxes operate on new separate VLANS over the cable plant. Add the legacy analog TV carriers, digital phone service, legacy digital cable TV, and docsis 3.0 multiple bonded channel cable modems, there are allot of upstream and downstream signals contributing to intermods and noise (including other foreign noise and interference sources) on your neighborhood cable plant.

I believe all of this can be managed but it will take a big effort on the part Cox network engineering. Not much evidence of this so far given the lack proactive responses we've seen.

I have asked Cox tech support to answer a simple question to which they have refused to answer. ARE OTHER SUBSCRIBERS IN MY NEIGHBORHOOD SHOWING UP IN THE CMTS FLAP LIST? This would be very telling because if they are seeing multiple upstream hits at the head end, it pretty much eliminates all of the individual modem and house wiring assumptions in their typical trouble shooting aproach.

I need my internet service to be reliable more than I need the extra upstream bandwidth that Cox cable offers over ADSL. That said, I have ordered and will receive CenturyLink 12/0.9 Mbs service next week. I will cancel Cox (after 7 years of service) if CenturyLink proves to be reliable.

This is a big hassle for me but I don't have confidence that Cox can clean house and turn things around anytime soon.

Same Issue here in Plaquemine, LA. we have had 3 techs come out, i replaced our router with a net gear one, and I am able to track the 30 second drops every 5 min or so. They said it was our router, however had the same issues, they replaced our motorola modem with a cisco one but it did not improve the situation. We never lose connection lights, however we do time out. I do not understand this. Cox can not isolate the issue either.

I switched over to Century Link 12 Mbs DSL two months ago. I have had no drop outs and very consistent bandwidth. I am a big user of streaming video (Netflix, Amason, Vudu...) and Ooma VoIP phone service. These work flawlessly now. If you are just using the Internet for email and web browsing... then keep Cox. However, I will not recommend cable modem Internet service to any of my friends because it is inherently unreliable.

Same problems here in Glendale, AZ with a Netgear Cable modem.  The Cisco reference posted in this thread gives some hints to the problem.  I think that there's simply too much traffic on this segment and the modem isn't getting its response from the Cox end in time, so it resets.

CenturyLink is a possibility for me as well ....

I am in the New Orleans, LA area and I too am having the same issues with the intermittent connection issuess  It has been going on since I got my Cox services about 2 weeks ago.  I have the Motorola SB6121 Docsis 3.0 modem.  I had a tech come out the other day and they said that Cox was having some issues with all Docsis 3.0 modems and that it was a problem locally to the New Orleans area.

Is this true? And if so, do we have an expected time when this will be resolved?