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boontonflyer

join:2004-07-05
Ringoes, NJ
Reviews:
·Comcast

2 edits

[Signals] DOCSIS 3.0 Modem Basic Error Rate

About two months ago Comcast sent me a new Arris TMS 722G cable modem.

Had no prior notice (or info with the package ) about why I was getting it.

I finally figured out it was because we now had the 50 Mb/sec // 10 Mb/sec speed tier and needed this modem to get the full performance of that tier.

The new modem has the four bonded channels to achieve this performance level.

Had done some looking to find out if I was getting the correct performance (ie. Basic Error Rate of 1 X 2^ - 8 is considered acceptable).

I copied the data from the page of the modem utility (accessible at 192.168.100.1 on the network) to an Excel spreadheet and set it up in "scientific notation" to see what performance I was getting.

Attached spreadsheet shows the data.

Apparently I'm getting 4 X 10 ^-7 BER over about a 30 day period.

Paul

Extide

join:2000-06-11
84129

Have you noticed any actual issues with your internet service? Pages not loading? Bad performance? I would say everything is OK, if you aren't actually experiencing any symptoms. Those uncorrectables don't seem to be too bad. Typically you will see a bunch of uncorrectables right as the modem starts, so I would say reboot the modem, wait about 10-15 mins and then note the # of uncorrectables. THEN monitor it over a period of time, and see what your long term error rates are. I bet your long term error rates will be significantly lower if you exclude the first 10-15mins.

The rest of your signal levels look just fine. What is your upstream power level ?


boontonflyer

join:2004-07-05
Ringoes, NJ
Reviews:
·Comcast

2 edits

I wasn't complaining about the performance of the new modem. I'm very happy with the performance of the EMTA and the higher speeds. I was just reporting what my experience was with the modem and putting forth the info to see if it was comparable to what other customers were getting.

Upstream

UCID Freq Power Channel Type Symbol Rate Modulation
Upstream 1 10 36.20 MHz 50.50 dBmV DOCSIS2.0 (ATDMA) 5120 kSym/s 64QAM
Upstream 3 11 29.40 MHz 50.00 dBmV DOCSIS2.0 (ATDMA) 5120 kSym/s 64QAM
Upstream 4 12 22.00 MHz 48.50 dBmV Mixed (TDMA and ATDMA) 2560 kSym/s 64QAM

Upstream power levels are fine. See above. The data I showed was for a 30 day period (ie 30 days uptime). If there were significant "startup anomalies" they would have gotten lost in the total amount of data recorded.

Paul

Edit on October 18,2012 :

Monitored the data on a daily basis for the last four days. It appears that the Correctable & Uncorrectable errors have stayed the same and the Octet processed goes up about 3 % per day . A "calculated estimate" would look like the Bit Error Rate will approach the EMTA spec capability in approximately 100 days. Have no way of knowing where the initial batch of errors occurred or any way to remove them.

I will reset the counters in about another week and see how the second set of data looks.

Paul


Extide

join:2000-06-11
84129
reply to boontonflyer

Well, if a LOT of the errors (like 60% or something) came from startup, yes it would mess up your averages.

Anyways, man, why does everyone but me get 3 upstream channels? I only get 2. And itlooks like you have 3 at 64QAM too.



EG
The wings of love
Premium
join:2006-11-18
Union, NJ
kudos:9

1 edit

said by Extide:

Anyways, man, why does everyone but me get 3 upstream channels? I only get 2.

Perhaps that is all that are configured / available on your local system / CMTS ? Perhaps the engineering group for your local area has decided that two are all that is needed to meet the local capacity demand ? Perhaps not enough QAM's have yet been freed up from the T.V. service on the local system for them to be able to offer more internet QAM's

n_w95482
Premium
join:2005-08-03
Ukiah, CA
reply to Extide

I have two upstream channels as well; one 64QAM, one 16 .
--
KI6RIT


Extide

join:2000-06-11
84129
reply to boontonflyer

said by EG:

said by Extide:

Anyways, man, why does everyone but me get 3 upstream channels? I only get 2.

Perhaps that is all that are configured / available on your local system / CMTS ? Perhaps the engineering group for your local area has decided that two are all that is needed to meet the local capacity demand ? Perhaps not enough QAM's have yet been freed up from the T.V. service on the local system for them to be able to offer more internet QAM's

Well, duh, obviously it was a rhetorical question.


EG
The wings of love
Premium
join:2006-11-18
Union, NJ
kudos:9

1 recommendation

"Obvious" to whom ? Not me, sorry.


Extide

join:2000-06-11
84129

Well, it's pretty obvious that the reason I only get 2 channels is because there are only two configured. Anyways, this is getting OT and will be my last post on the topic.



EG
The wings of love
Premium
join:2006-11-18
Union, NJ
kudos:9

1 recommendation

Pardon me for taking it literally and just sincerely trying to provide you with some information which I could not possibly know whether you already know or not. Have a nice day sir !


boontonflyer

join:2004-07-05
Ringoes, NJ
Reviews:
·Comcast
reply to boontonflyer

Technical Follow-UP Note: Have been monitoring EMTA data over the last several months. Seems like "Correctable Bit Error Rate" is ~~ 10^ -9 and "Un-Correctable Error Rate is ~~ 10^ -7 !! Only upsets seem to be occasional event log entries like (MTA TFTP: Successful
11/25/2012 12:12 26 MTA PROV: Successful!).

Very satisfied with the new TMS 722G performance !!

Paul