Basic Internet Connectivity And Modem Help

[MissyLaneous]

Apparently, my Motorola sb 6120 has been having fits last night and one just now (e.g. 4:50-ish am EST).  This is the weirdest (to me):

Jan 01 1970 00:00:31

3-Critical

D05.0

TFTP failed - Request sent - No Response

That one just occurred - the rest of the log are filled with Jan 01 entiries.

Is this "TFTP" something extraordinarily bad?  Any advice, please?

Thanks in advance.

[MissyLaneous]

UPDATE:  Just power-cycled modem, cleared cache/cookies and dns cache and ONLY ONE CHANNEL BONDED.  Used to be two channels as of a month or so ago. 

Is it Comcast with the issues, or just lucky me? 

Thanks in advance.

[kevj]

Not sure about the single channel bonding issue, but TFTP is the protocol the modem uses to connect to the server from which it receives its configuration files and (probably) firmware updates. If the modem cannot connect to that server, it is possible that out is not getting the correct configuration file.

[MissyLaneous]

Thanks, but now what do I need to do for the correct configuration file?  Do I HAVE to call Comcast ?  If so, any suggested verbage to tell them?

I'm noticing it is taking a-g-e-s to connect to anything on Comcast and my upload speed is like 87kb.  Grrr.

[UHFhd]

      From all the post about 6120 motorola modems it would seem there is a configuration file (firmware) being sent to the modems thats is unstable to say the least . 

[kevj]

Unfortunately this is situation where you would have to call in. You could also try emailing we_can_help@comcast.com, and describe the issue to them. You could also provide a link to this thread.
I don't think there is too much anyone here can do about it...

[EG]

What do the modem's signal stats look like ? Try getting them here; http://192.168.100.1

Please post the *Downstream Power Level*, the *Upstream Power Level*, and the *SNR* (Signal to Noise Ratio) numbers.

Any type of RF signal, connection quality, upstream or downstream path impairment that causes the modem and the CC system (CMTS) to not be able to talk to / hear each other can cause this to occur. Out of spec signal stats and/or noise ingress are the typical offenders.

As far as the "single channel" that the modem is now connected to now, this can be due to the CMTS calling for a DCC (Dynamic Channel Change) where a bad (noisey or congested) channel gets disabled in favor of a cleaner channel to communicate on. This happens on the fly and can change again at any given moment.

[MissyLaneous]

Here are current modem stats.  FWIW, can't even run ShaperProbe and the other 'speed' tests show 0.01 upload speed, lol.  Comcast swapping modem tomorrow (hopefully).  Comcast phone agent said she saw my modem not getting power frequently.   THANKS FOR ANY OTHER ADVICE.

Channel ID	57	58	59	60
Frequency	579000000 Hz	585000000 Hz	591000000 Hz	597000000 Hz
Signal to Noise Ratio	37 dB	37 dB	37 dB	37 dB
Downstream Modulation	QAM256	QAM256	QAM256	QAM256
Power Level The Downstream Power Level reading is a snapshot taken at the time this page was requested. Please Reload/Refresh this Page for a new reading	4 dBmV	4 dBmV	4 dBmV	5 dBmV

Upstream Bonding Channel Value

Channel ID	2
Frequency	27900000 Hz
Ranging Service ID	194
Symbol Rate	5.120 Msym/sec
Power Level	42 dBmV
Upstream Modulation	[3] QPSK [3] 64QAM
Ranging Status	Success

[EG]

The stats as read at the modem level at that moment in time were o/k. But there are two additional signal stats which can't be read at the modem level. They can only be read from their end by them polling the CMTS (Cable Modem Termination System) at the local headend facility.

They are the 'Upstream Receive Power Level' and the 'Upstream uSNR' (upstream Signal To Noise Ratio). Both of these are as equally important in diagnosing connectivity issues as are the modem's stats.

You can call in and ask what these figures are. The Upstream Receive Power Level should fall within the range of -10dB to +10dB with 0dB being in the middle and perfect.

The Upstream SNR should be least 30dB, and the higher it is the better. You could have a noise ingress issue in the upstream channel/s only

[MissyLaneous]

Hello all,

Comcast tech grudgingly (!!) replaced my leased s/b 6120 with an Arris.  Would someone here kindly look at my modem power levels below and advise if they are okay, please.  Also, is this Arris WBM760a actually DOCSIS 3.0 ?  (The tech was really surly so not sure if I should believe him.)

THANKS IN ADVANCE ..!

Downstream

	DCID	Freq	Power	SNR	Modulation	Octets	Correcteds	Uncorrectables
Downstream 1	60	597.00 MHz	1.73 dBmV	37.09 dB	256QAM	6603302	0	0
Downstream 2	57	579.00 MHz	1.62 dBmV	37.09 dB	256QAM	6322512	0	0
Downstream 3	58	585.00 MHz	1.33 dBmV	37.09 dB	256QAM	6992038	0	0
Downstream 4	59	591.00 MHz	1.28 dBmV	36.84 dB	256QAM	5735372	0	0

Reset FEC Counters

Upstream

	UCID	Freq	Power	Channel Type	Symbol Rate	Modulation
Upstream 1	2	27.90 MHz	42.00 dBmV	DOCSIS2.0 (ATDMA)	5120 kSym/s	64QAM

[EG]

That signal stats that can be read from the modem are all well within spec.

[MissyLaneous]

Thanks, EG .. you "guys" here are The Best. 

Appreciate you having a look at power levels.  New modem, new things to worry about :-)

[EG]

My pleasure ! It's why we lurk !! Happy surfing !

[BruceW]

The 0/0 "Correcteds/Uncorrectables" is especially good. We should all be so lucky!

[EG]

Yes that is indeed good, but I will add that a reboot erases the previous data and starts the counters going again, so the length of the time period that these errors are being recorded needs to be factored in.

[MissyLaneous]

Help again - please ...!  This new Arris has dropped in and out 3x since 2 a.m.  NOW I have 3 upload channels (what happened to #2?) and lots of uncorrectables.

WORSE, when I was directly connected I got directed to a Comcast sign up page because the tech supposedly didn't register my modem correctly?

Downstream 1	60	597.00 MHz	0.93 dBmV	37.09 dB	256QAM	19937695	0	0
Downstream 2	57	579.00 MHz	1.09 dBmV	37.09 dB	256QAM	18680789	0	0
Downstream 3	58	585.00 MHz	0.81 dBmV	37.09 dB	256QAM	18282113	13	592
Downstream 4	59	591.00 MHz	0.83 dBmV	36.84 dB	256QAM	17981632	47	647

Upstream 1 2 27.90 MHz 42.00 dBmV DOCSIS2.0 (ATDMA) 5120 kSym/s 64QAM
Upstream 3 1 34.80 MHz 42.50 dBmV DOCSIS2.0 (ATDMA) 5120 kSym/s 64QAM
Upstream 4 3 22.60 MHz 41.50 dBmV DOCSIS1.x (TDMA) 2560 kSym/s 16QAM

[EG]

You signals are fine and there is nothing wrong with having three bonded upstreams now unless they are noisey. Seems that the modem may have went down at that time due to them upgrading the upstream. The overnight hours are their maintenance window. Not much else that we can do for you here, you need to call this in.

[MissyLaneous]

Thanks.  Sounds like I don't need to call then if levels not noisy ?

Really DO apologize if being a worrisome pest (beats cleaning litter trays).  *sends brownies as Thank You*

[EG]

No worries. Only they can see from their end if the upstreams are noisey. See what happens over the next couple of days as the bugs typically need to be worked out. If you still have a problem then you need to call in and report it.