Random disconnections from a Terayon TJ715x cable modem?

As Emily Litella would say: "Never mind".

OK! I finally got the new modem (Ambit U10C018) working since 12:40 PM PDT. Man, it's tiny!

The bad news. I think I got disconnected again like five minutes ago. Nothing odd in cable modem log: First Time Last Time Counts Level ID Text Sat Oct 04 20:10:48 2008 Sat Oct 04 20:10:48 2008 1 Warning (5)

68010300 DHCP RENEW WARNING - Field invalid in response Time Not Established Time Not Established 1 Critical (3) 68000300 DHCP WARNING - Non-critical field invalid in response. Time Not Established Time Not Established 2 Critical (3) 82000200 No Ranging Response received - T3 time-out Time Not Established Time Not Established 1 Critical (3) 68000300 DHCP WARNING - Non-critical field invalid in response. Time Not Established Time Not Established 1 Critical (3) 68000100 DHCP FAILED - Discover sent, no offer received Time Not Established Time Not Established 2 Critical (3) 82000200 No Ranging Response received - T3 time-out Time Not Established Time Not Established 15 Critical (3) 68000300 DHCP WARNING - Non-critical field invalid in response. Time Not Established Time Not Established 1 Critical (3) 68000100 DHCP FAILED - Discover sent, no offer received Time Not Established Time Not Established 1 Critical (3) 68000300 DHCP WARNING - Non-critical field invalid in response. Thu May 15 00:12:10 2008 Thu May 15 00:12:10 2008 1 Critical (3) 82000400 Received Response to Broadcast Maintenance Request, But no Un... Tue May 13 23:14:58 2008 Tue May 13 23:14:58 2008 1 Critical (3) 82000500 Started Unicast Maintenance Ranging - No Response received - ... Time Not Established Time Not Established 7 Critical (3) 68000300 DHCP WARNING - Non-critical field invalid in response. Time Not Established Time Not Established 1 Critical (3) 68000200 DHCP FAILED - Request sent, No response Time Not Established Time Not Established 6 Critical (3) 68000300 DHCP WARNING - Non-critical field invalid in response. Time Not Established Time Not Established 1 Critical (3) 68000200 DHCP FAILED - Request sent, No response Time Not Established Time Not Established 3 Critical (3) 68000300 DHCP WARNING - Non-critical field invalid in response. Wed Apr 30 01:02:25 2008 Wed Apr 30 01:02:25 2008 4 Critical (3) 82000200 No Ranging Response received - T3 time-out Wed Apr 30 01:02:03 2008 Wed Apr 30 01:02:03 2008 1 Critical (3) 82000400 Received Response to Broadcast Maintenance Request, But no Un... Wed Apr 30 01:01:31 2008 Wed Apr 30 01:01:31 2008 16 Critical (3) 82000500 Started Unicast Maintenance Ranging - No Response received - ... Time Not Established Time Not Established 2 Critical (3) 68000300 DHCP WARNING - Non-critical field invalid in response. Tue Apr 29 22:49:18 2008 Tue Apr 29 22:49:18 2008 8 Critical (3) 82000200 No Ranging Response received - T3 time-out Tue Apr 29 22:48:10 2008 Tue Apr 29 22:48:10 2008 1 Critical (3) 82000400 Received Response to Broadcast Maintenance Request, But no Un... Tue Apr 29 22:47:37 2008 Tue Apr 29 22:47:37 2008 12 Critical (3) 82000500 Started Unicast Maintenance Ranging - No Response received - ... Time Not Established Time Not Established 72 Critical (3) 84000100 SYNC Timing Synchronization failure - Failed to acquire QAM/Q... Time Not Established Time Not Established 85 Critical (3) 84000200 SYNC Timing Synchronization failure - Failed to acquire FEC f... Time Not Established Time Not Established 17 Critical (3) 68000300 DHCP WARNING - Non-critical field invalid in response. Mon Apr 14 00:10:52 2008 Mon Apr 14 00:10:52 2008 8 Critical (3) 82000200 No Ranging Response received - T3 time-out Mon Apr 14 00:08:10 2008 Mon Apr 14 00:08:10 2008 1 Critical (3) 82000400 Received Response to Broadcast Maintenance Request, But no Un... Mon Apr 14 00:07:37 2008 Mon Apr 14 00:07:37 2008 16 Critical (3) 82000500 Started Unicast Maintenance Ranging - No Response received - ... Thu Apr 10 20:36:58 2008 Thu Apr 10 20:36:58 2008 1 Critical (3) 68000300 DHCP WARNING - Non-critical field invalid in response. Thu Apr 10 20:35:26 2008 Thu Apr 10 20:35:26 2008 6 Critical (3) 82000200 No Ranging Response received - T3 time-out Thu Apr 10 20:34:52 2008 Thu Apr 10 20:34:52 2008 1 Critical (3) 82000400 Received Response to Broadcast Maintenance Request, But no Un...

I guess I will have to another router or hook up the PC directly to the computer and see how that goes.

Snip, snip...

How is your replacement cable modem doing now?

So far, it fixed my long desynchronizations I had on Friday so I gave up and swapped modems on Saturday. I could confirm that touching the coax cable connector to the cable modem would cause to desynch easily. Even if I don't touch it, it can do the same like on Friday. It doesn't feel lose. Did I mention that the coax cable connector's needle/pin is a little bent? I tried to unbent/straighten it, but it is a little bent. I don't know if this is related.

After the cable modem swap, I haven't had those desynchronizations anymore. I only still have those quick annoying one second disconnections like with the old Terayon modem. I checked the modem's event logs and nothing odd (nor logged about those quick disconnections) from them.

I still haven't been able to try the cable modem to a computer/notebook since others house members use my Internet even at late night hours. Since it takes 10-15 hours to reproduce the random quick disconnections, I need to wait when things are quiet (hopefully at the end of this month). I don't have another router to borrow to try either.

Yep, it is confirmed that my old quick disconnection issue from my old Netgear RT311 router to the new Ambit cable modem remains:

$ ping 192.168.100.1 ...

64 bytes from 192.168.100.1: icmp_seq=283 ttl=63 time=5.09 ms From 192.168.0.1 icmp_seq=284 Destination Host Unreachable From 192.168.0.1 icmp_seq=285 Destination Host Unreachable From 192.168.0.1 icmp_seq=286 Destination Host Unreachable From 192.168.0.1 icmp_seq=287 Destination Host Unreachable 64 bytes from 192.168.100.1: icmp_seq=288 ttl=63 time=5.31 ms ... ^C

--- 192.168.100.1 ping statistics ---

711 packets transmitted, 707 received, +4 errors, 0% packet loss, time 712845ms rtt min/avg/max/mdev = 4.713/7.099/159.370/11.875 ms

Nothing in cable modem's Cable Modem Event Log page about the quick disconnections either.

However... Yesterday, I had a couple long disconnections (a few minutes long) when I was not at home. I don't know if those were related to my quick disconnections or something else (hopefully just hiccups and haven't had anymore last night and today so far).

On 10/08/2008 07:47 AM, Ant sent:

Snip, snip...

The R.F. side of the cable modem still has not been eliminated. This includes your house's coaxial cable, connector(s) and your service provider's outside plant.

A methodical approach must be utilized when a failure occurs such that the downstream/receive signal level and downstream/receive SNR should be captured that coincides with the failures.

I am still not absolutely sure that you have been able to log into your new/Ambit cable modem's web pages. Also, the issue of the house coaxial cable and its "F" connector didn't seem to have been ruled out.

Can you relay any downstream signal/SNR levels? Do you still have Internet drop outs if the house coaxial cable/connector are slightly flexed at the rear of the Ambit cable modem?

Pete

I can log in from GUI Web browsers like IE6 and Firefox. However, I keep missing the quick disconnections to check the statistics and I am minutes/hours too late. I wished there was a way to log the modem's statistics every minute like I did on my old modem. Darn modem using ASP or some funky Web pages to make Lynx and eLinks not render correctly. Same for logging in (401 errors) with Perl scripts.

I assume you want me to get the levels and other information right after a quick disconnection. If so, then I will have to try that right after (seconds later) those quick disconnects. What's more annoying, statistics are separated by Web pages and not all together like my last modem. Bah.

What did you mean by flexed? Unscrew and losen the coax connection from the modem?

I'd go call them and ask if the cable office has any other brand that you might find more conducive to polling. Maybe another Terayon.

Do you still have reason to believe you're having a modem/RF problem? I haven't been following the thread that closely, but I thought you replaced the modem and still suffer from short term disconnections, which would lead me to believe the problem is elsewhere.

Flex = bend, as in slightly bend, to see if there is a loose connection.

On 10/08/2008 04:10 PM, Bill M. sent:

Yes, his cable modem has been exchanged. However, the quality of the present Ambit U10C018 is an unknown quantity. Personally I have received multiple intermittently failing replacement equipment from my own service provider until I announced my intentions to discontinue my patronage with any more failed units. Only at that point was an obvious brand new unit placed in my hands. No more failures then.

The reason for the mild flexing is that a failure was noted when the OP touched the coax and/or "F" connector at the Terayon cable modem. It isn't totally clear if this has ceased with the Ambit. The premises cabling goes back to 2000 and it's undetermined if the cable lengths, and coax/connector, are well rated or are sufficient for 705 GHz data service. I'm trying my best to assist our OP in determining the point of failure without having him to schedule/pay for an ISP technician calls or an electrician to run known quality RG6 from the demarc to the cable modem. ...and of course the ISP's local outside plant cabling is an unknown quantity too, at this time.

The OP's previous posts have shown marginal downstream SNRs (29 dB) that vary 4 dB and possibly more.

Pete

On 10/08/2008 02:50 PM, Ant sent:

All the immediately interesting readings are on the "Downstream" page.

Although an ideal reading of the Downstream signal level, and SNR, would be in the midst of a failure, I realize how difficult this may be without a running script. For right now, lets have you take an instantaneous reading and relay that. It wouldn't hurt to take just the downstream signal level and downstream SNR readings hourly or every two hours or so. We need to establish some kind of a new baseline since the Ambit modem is now in play. This is important!

When you installed the Ambit modem, you screwed the house R.F. cable to the replacement Ambit modem and tightened its connector, with a 7/16" open-end wrench or its equivalent, such that the cable's "F" connector is *slightly* more than finger tight. Now you should be able to observe your systems when you ever so *slightly* bend the R.F. cable back and forth taking note whether anything fails. We are looking for an intermittent connection - either in the cable, at the connector, or in the cable modem at the coax connector.

Pete

I did ask for Motorola since someone told me that it was a good brand, but the gal said no and she said Ambit was the only one.

I assume it is not the modem since the symptoms are the same like my old Terayon cable modem from 2005. Someone suggested to try without my old Netgear RT311 router with a direct connection (have to wait for other house members not to use the Internet much) or another router (might be able to get an used Linksys to test it). I already tried different cat5 cables (new vs. old) between the router and cable modems.

I flexxed/bented the cable part 360 degrees in circle (didn't force it hard) while holding the modem so it won't move. It didn't disconnect me. I checked my cable modem's logs to verify (no errors).

Mine looks new, but how can I be sure that it is not refurbished, used, etc.? I noticed the logs said defaults used or something (cleared the logs a few days ago so I can't paste what I saw).

That issue seems to be gone (it better be) hence forced me to swap modems. I just have these random quick disconnections (1 second long). I don't know what yesterday's longer disconnections were. They might have been something else.

3/10/2001 according to my original Excite@Home Adelphia contract. :) Yep, it was that long ago. Oy, that cable service was horrible back then. Much worse than I am going through because everything on their side for the whole city (not DOCSIS!) until 2003(?), Adelphia upgraded the cable infrastrucutre in the city.

When you say plant, is that the little green box in the ground? If so, then there's one across the street from where I am.

Here are my current statistics (haven't been disconnected since before

7:47 AM PDT, and I am sure another one is soon [12-15 hours usually]):

Cable Modem Information Cable Modem : DOCSIS 1.0/1.1/2.0 Compliant MAC Address : [snipped] Serial Number : [snipped] Boot Code Version : 2.1.6d Software Version : 2.93.1008 Hardware Version : 1.20

Cable Modem Status Item Status Comments Acquire a Downstream Channel 705000000 Hz Locked Connectivity State OK Operational Boot State OK Operational Security Enabled BPI+

Cable Modem Downstream Downstream Lock : Locked Downstream Channel Id : 71 Downstream Frequency : Downstream Modulation : QAM256 Downstream Symbol Rate : 5360537 Downstream Interleave Depth : 32 Downstream Receive Power Level : -1.5 dBmV Downstream SNR : 34.4 dB

Cable Modem Upstream Upstream Lock : Locked Upstream Channel ID : 7 Upstream Frequency : Upstream Modulation : QAM16 Upstream Symbol Rate : 2560 Ksym/sec Upstream transmit Power Level : 39.0 dBmV Upstream Mini-Slot Size : 4

Cable Modem Upstream Burst REQ Init Per Short Long Maint Maint Data Data (1) (3) (4) (5) (6) Modulation Type QPSK QPSK QPSK 16QAM 16QAM Differential Encoding Off Off Off Off Off Preamble Length 64 640 384 168 192 Preamble Value Offset 652 0 0 720 720 FEC Error Correction (T) 0 5 5 6 8 FEC Codeword Information Bytes (k) 16 34 34 78 220 Scrambler Seed 338 338 338 338 338 Maximum Burst Size 0 0 0 23 255 Guard Time Size 8 48 48 8 8 Last Codeword Length Fixed Fixed Fixed Short Short Scrambler on/off On On On On On

Cable Modem Operation Configuration Network Access : Allowed Maximum Downstream Data Rate : 0 Maximum Upstream Data Rate : 0 Maximum Upstream Channel Burst : 0 Maximum Number of CPEs : 1 Modem Capability : Concatenation Enabled, Fragametation Enabled, PHS Enabled

Cable Modem Event Log is empty (cleared it recently to start new).

Oy! Copying, pasting, and tweaking is annoying from seven ASP Web pages. I think I am going to do screen captures next time.

See anything interesting? I noticed this Ambit modem provides more details than my previous modems. I guess that's good for us to have more details?

HA! A few minutes later after my post, I got disconnected again. I think it is watching me. :P I think I got the datas within five minutes after the quick disconnection:

for screen captures (I tried to collect fast as I could!).

In broad brush strokes, I'm using some terms from my own earlier career. Loosely speaking, inside plant would be any and all equipment your service provider has before the signals leave their building(s).

Again, in the loosest of terminologies, outside plant is the equipment outside /their/ main building(s) that conveys the signals from them towards your demarcation point.

"the little green box in the ground" if it contains any of your provider's equipment, is part of their outside plant.

The demarcation point, or demarc, is somewhat legal and technical. It's typically (not always) in/on your property. Equipment on your side of the demarc is the rate payer's/subscriber's/patron's responsibility. Even if the original cable company installed your home's coaxial cabling, you could/should bear the expense of maintenance. This is an *extremely* gray area. Many cable companies want you to maintain any and all equipment on your side of the demarc. However, the cable company techs may be permitted to run new or replace old cabling just to make the customer happy. However, just as often, the cable company techs will direct you to use the services of an electrician or imply that you can DIY.

Snipped

Snipped

I would *not* have done this. You may wish to rethink this if you are tempted to do this again.

At the time you took this snapshot of conditions, the "Downstream Receive Power Level : -1.5 dBmV" is excellent by almost any standard. Loosely speaking, 0 dBmV is the ideal with a +/- 12 dBmV range of acceptability.

The "Downstream SNR : 34.4 dB" is acceptable. For QAM256 modulation, a number more positive than 33.0 dB is OK. Would be nicer if this was more positive than 35 dB. These numbers will vary with time of day, temperature and many factors in, but mostly out of your control. When your downstream SNR was 29.0 dB, technically this was 4 dB in the bad area. Keep monitoring this! I am suspicious that this condition might yet return!

At the instant of this failure, was your Netgear RT311 router part of the overall configuration?

OK. I was trying to keep my logs clean. The list is messy since they are not sorted chronologically.

Will do. Here's one as I type this post:

Cable Modem Downstream

Downstream Lock : Locked Downstream Channel Id : 71 Downstream Frequency : Downstream Modulation : QAM256 Downstream Symbol Rate : 5360537 Downstream Interleave Depth : 32 Downstream Receive Power Level : -1.9 dBmV Downstream SNR : 35.0 dB

Haven't had any more disconnections since I mentioned last night.

That is correct. I have gotten the old Linksys that I am going to try with or a chance to try a direct connection to a computer. Maybe this weekend?