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Regular Contributor
hongzhang
Posts: 48
Registered: ‎05-31-2012

Frequent internet outage in Eastern MA

I have been experiencing frequent internet outage recently.  It has happened 3 times so far.  I am wondering if anyone in Eastern Mass is experiencing the same.

 

I do not have any hardware change.  The cable, modem, router, computers all are the same. It usually comes back after I cycle the power of the modem a few times.  Actually, I am not sure cycling the power does anything useful.  The outage may just last as long as the time I cycle the power.  I cycled the power today a dozen times to no avail, then started a chat session with their technical support.  I cycled the power a few more times, and she sent some signla to it.  Eventually, it came back suddenly. I seriously doubt all the power cycling or signal sending does anything to this. 

Regular Problem Solver
Posts: 2,846
Registered: ‎11-02-2003

Re: Frequent internet outage in Eastern MA

Please post your modem signal levels....

Find them at http://192.168.100.1 or http://10.0.0.1

Someone will be able to give you a hand....

Thanks!

Regular Contributor
hongzhang
Posts: 48
Registered: ‎05-31-2012

Re: Frequent internet outage in Eastern MA

Thank you so much for the tip.  I wish had known this earlier.  I will look into this when the problem occurs next time.  The current signal of the modem is as the following:

 Downstream            Value

Frequency699000000 Hz 
Signal to Noise Ratio35 dB 
QAMQAM256
Network Access Control ObjectON
Power Level-4 dBmV  
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
Upstream Value
Channel ID5
Frequency36800000 Hz
Ranging Service ID7231
Symbol Rate5.120 Msym/s
Power Level54 dBmV 

 

Connection Expert
EG
Posts: 43,084
Registered: ‎12-24-2003

Re: Frequent internet outage in Eastern MA

[ Edited ]

The upstream power is too high and may be intermittently fluctuating even higher out of spec. The downstream power is a tad weak as well. In an effort to obtain better connectivity, are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured ? Any splitters that remain should be high quality and cable rated for 5-1000 MHz, bi-directional, and no gold colored garbage from Radio Shack, Home Depot, etc.

 

If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two way splitter connected directly off of the drop from the street/pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then putting them back together again, then perhaps it's best to book a tech visit to investigate and correct.

 

What is the exact make and model number of the modem ?

Regular Contributor
hongzhang
Posts: 48
Registered: ‎05-31-2012

Re: Frequent internet outage in Eastern MA

Thanks for the diagnosis.

 

Yes, there are two splitters.  The modem is Motorola Corporation sb5120.

 

I have had this configuration for at least 6 years. It worked quite well until Nor'Easter Blizzard Nemo a few weeks ago when I lost the internet connection for almost 2 days. They scheduled a technician to come to check it, but just before the scheduled time, it was canceled and I was told there was a problem for the whole block.  They apparently fixed that problem.  Since then, I have been experiencing a few outages every week instead of a few times every year normally.

Actually, I suspected the cables and splitters though I have not touched them for years, so I moved the modem close the jack and connected the modem to it with a short cable, but the problem remained at least for the case that I tested in this way.   

I asked this question primarily to see if anyone else in Eastern Mass experiencing this post-Nemo syndrome. I have learned quite a few things, so I will look at these numbers next time when the outage occurs.

 

 

 

 

Software Version: SB5120-2.19.0.16-SCM00-NOSH
Hardware Version: 4
MIB Version: II
GUI Version: 1.0
VxWorks Version: 5.4

Connection Expert
EG
Posts: 43,084
Registered: ‎12-24-2003

Re: Frequent internet outage in Eastern MA

You don't have any wiggle room right now, so a physical intervention would seem to be needed ASAP..

Regular Contributor
hongzhang
Posts: 48
Registered: ‎05-31-2012

Re: Frequent internet outage in Eastern MA

OK, I will move the modem to the jack again for testing, this will require moving the router along with it so that I can read the signal data again.  I will post the results later.  The Downstream powerlevel is -2 dBmV right now, but the upstream power level remains at 54dBmV.

Connection Expert
EG
Posts: 43,084
Registered: ‎12-24-2003

Re: Frequent internet outage in Eastern MA

Again. If you can't get the upstream power below 50 dB (45 would be nice), then you'll need a tech to investigate. The problem may be beyond your premises.

Regular Contributor
hongzhang
Posts: 48
Registered: ‎05-31-2012

Re: Frequent internet outage in Eastern MA

OK, I will ask Comcast.

Regular Contributor
hongzhang
Posts: 48
Registered: ‎05-31-2012

Re: Frequent internet outage in Eastern MA

They think the modem may be problematic, so I am going to get a new modem.

 

Here is the whole story.

 

I spent more than half an hour chatting with one rep, and she did a lot of things on their side and was confident the ultra high upstream power level was fixed.  After power cycling, it remaine at 54 dBmV.

 

I started another chat session, and she also did a bunch of things on their side, but problem remains.  She concluded that modem may be problematic.

 

I got rid of all the splitters and connected to modem to the jack via the long cable provided by Comcast when I subscribed to the service.  The new power levels are:

Downstream: 5 dBmV

Upstream: 50 dBmV.

 

Apparently, the upstream power level is still too high, so I am going to get a new SB6121 to see if the problem will be fixed. I will report back.

 

Thank you for your advice. 

 

 

Connection Expert
EG
Posts: 43,084
Registered: ‎12-24-2003

Re: Frequent internet outage in Eastern MA

[ Edited ]

If you are buying that modem make sure the store has a return policy. If this is indeed a line issue, the issue will still be there no matter what modem is used.

 

Also be advised that there have been / are boatloads of posts here indicating many issues with that modem and its firmware. It also only offers 4x4 channel bonding when you can get a more current modem that offers 8x4 channel bonding such as the SB6141 or the Zoom 5341J for close to the same price.

Regular Contributor
hongzhang
Posts: 48
Registered: ‎05-31-2012

Re: Frequent internet outage in Eastern MA

Thank you.  I am aware of the risk. I will report back as soon as I test the new modem.

Connection Expert
EG
Posts: 43,084
Registered: ‎12-24-2003

Re: Frequent internet outage in Eastern MA

See my latest edit above as well.

Regular Contributor
hongzhang
Posts: 48
Registered: ‎05-31-2012

Re: Frequent internet outage in Eastern MA

Thank you for the tip.  That modem sounds scary. I picked that from the list provided by a Comcast chat rep:

http://mydeviceinfo.comcast.net/

 

SB6121 is the only one from Mororola that is D3 with 3-start certification.  I am going to look into others per your tip.

 

Connection Expert
EG
Posts: 43,084
Registered: ‎12-24-2003

Re: Frequent internet outage in Eastern MA

Those star ratings indicate a certain level of testing that has so far been done on the modems and is not to be confused directly with performance / quality.

Regular Contributor
hongzhang
Posts: 48
Registered: ‎05-31-2012

Re: Frequent internet outage in Eastern MA

I have just ordered the last Zoom 5341J in stock. I should get it next week.  It has received rave reviews. Thank you again. Have a great weekend!

Connection Expert
EG
Posts: 43,084
Registered: ‎12-24-2003

Re: Frequent internet outage in Eastern MA

I'm using one as we speak. Probably the best modem I have ever had and I've had many. Please post back with how things turn out. I still have a feeling that you may need to have the line checked out but this modem seems to be very forgiving about less than stellar signals / connection quality.

Regular Contributor
hongzhang
Posts: 48
Registered: ‎05-31-2012

Re: Frequent internet outage in Eastern MA

I received the modem (CastleNet Technologies Inc. 5341j) yesterday, set it up a moment ago. 

 

Just as we were afraid of, the upstream power level remains exaactly the same:

Upstream Bonded ChannelsChannel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power

1LockedATDMA55120 Ksym/sec36800000 Hz54.0 dBmV
2LockedATDMA45120 Ksym/sec30400000 Hz54.0 dBmV
3Not LockedUnknown00 Ksym/sec0 Hz0.0 dBmV
4Not LockedUnknown00 Ksym/sec0 Hz0.0 dBmV
Connection Expert
EG
Posts: 43,084
Registered: ‎12-24-2003

Re: Frequent internet outage in Eastern MA

Not surprised. Book a tech.

Regular Contributor
hongzhang
Posts: 48
Registered: ‎05-31-2012

Re: Frequent internet outage in Eastern MA

[ Edited ]

I spent another hour or two on chats with Comcast (I am depressed whenever thinking about how much time I have spent on this).  One analyst suspected my router was problematic, I connected the modem a computer to satisfy her suspescion, and as expected, it did not make any difference.  After asking all kinds of questions, one of them eventually booked a technician. 

 

Let me state again that I rushed to purchase a brand new modem to fix the problem according the suggestion of Comcast. 

 

I will report back after the tech comes. 

Connection Expert
EG
Posts: 43,084
Registered: ‎12-24-2003

Re: Frequent internet outage in Eastern MA

Sorry to hear about all your troubles but what would you like me to say. I'm just a customer like you.

Regular Contributor
hongzhang
Posts: 48
Registered: ‎05-31-2012

Re: Frequent internet outage in Eastern MA

I am sorry if my tone sounds like blaming you who have helped a lot here. I am just frustrated with Comcast for multiple issues. 

 

I really appreciate all your kind advice.

 

Hong

Connection Expert
EG
Posts: 43,084
Registered: ‎12-24-2003

Re: Frequent internet outage in Eastern MA

[ Edited ]

O/k no worries. I completely understand your frustration ! Best of luck with this ! :smileyhappy:

Regular Contributor
hongzhang
Posts: 48
Registered: ‎05-31-2012

Re: Frequent internet outage in Eastern MA

Update:

 

A tech came yesterday, and found the upstream power level from the jack is 50 dBmV.  He believes it is too high.  For some reason, another appointment needs to be scheduled.

 

Purchasing the new modem per Comcast's suggestion is a waste of time and money.  The new modem provides the same speed as the old one based on my multiple tests.

 

Does Comcast throw these costly suggestions at their customers wihtout any consequences for itself?  

Connection Expert
EG
Posts: 43,084
Registered: ‎12-24-2003

Re: Frequent internet outage in Eastern MA


hongzhang wrote:

 

Purchasing the new modem per Comcast's suggestion is a waste of time and money.  The new modem provides the same speed as the old one based on my multiple tests.

 

Does Comcast throw these costly suggestions at their customers wihtout any consequences for itself?  


O/k here's an F.Y.I. on modems for ya';

 

There are benefits to be had by using a D3 capable modem on an upgraded to D3 system system regardless of one's subscribed to speed tier such as increased connection reliability due to the multiple bonded channel redundancy and failover capability. There are also increased capacity/reduced congestion benefits which result in increased reliability of receiving one's provisioned speeds especially during times of peak usage/demand. Higher Powerboost assisted speeds have been noted as well. Having a "fatter pipe" is a win win for both the provider and the subscriber.

 

 

 

Regular Contributor
hongzhang
Posts: 48
Registered: ‎05-31-2012

Re: Frequent internet outage in Eastern MA

[ Edited ]

Thanks for the information.  It makes me feel better.

 

Update (a very long story shortened):

 

A Comcast tech came yesterday. The findings are:

1. The US power level was confirmed again to be excessively high.

2. The cables to my jack may be old and cause a bit more than normal signal drop.

3. The most important finding is there was some serious problem somewhere outside the building.

 

The tech immediately requested maintenance service yesterday morning.  I saw a Xfinity service van earlier today, so I assumed it did the maintenance.  I have just checked the connection, the US power level dropped a whopping 10 dBmV.

As for the original Comcast analyst’s wrong diagnosis of modem problem that wasted me a lot of time and money, the tech basically blamed me for owning my modem, not leasing one from Comcast.

In summary of this saga:  there was some cable connectivity issue outside the building after blizzard Nemo, I started to lose Internet connection, spent a lot of time communicating with Comcast tech support, and bought a brand new modem following Comcast’s suggestion.  Comcast eventually fixed the problem that has nothing to do with the modem.  As for cause of the large waste of time and money caused by this, Comcast points to my owning my modem, not renting theirs.

 

Upstream Bonded Channels

Channel

Lock Status

US Channel Type

Channel ID

Symbol Rate

Frequency

Power

1

Locked

ATDMA

5

5120 Ksym/sec

36800000 Hz

46.8 dBmV

2

Locked

ATDMA

4

5120 Ksym/sec

30400000 Hz

45.5 dBmV

3

Not Locked

Unknown

0

0 Ksym/sec

0 Hz

0.0 dBmV

4

Not Locked

Unknown

0

0 Ksym/sec

0 Hz

0.0 dBmV

 

Connection Expert
EG
Posts: 43,084
Registered: ‎12-24-2003

Re: Frequent internet outage in Eastern MA

Good to hear ! For curiosity's sake, what does the downstream power and the SNR look like now ?

Regular Contributor
hongzhang
Posts: 48
Registered: ‎05-31-2012

Re: Frequent internet outage in Eastern MA

Downstream Bonded ChannelsChannel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables

1LockedQAM25680711000000 Hz-7.7 dBmV40.2 dBmV128243970
2LockedQAM25673669000000 Hz-9.4 dBmV36.0 dBmV44113754
3LockedQAM25674675000000 Hz-8.3 dBmV37.2 dBmV36592514
4LockedQAM25675681000000 Hz-8.8 dBmV38.2 dBmV67292094
5LockedQAM25676687000000 Hz-8.3 dBmV39.8 dBmV51602204
6LockedQAM25677693000000 Hz-8.4 dBmV39.9 dBmV2016210319
7LockedQAM25678699000000 Hz-8.0 dBmV38.6 dBmV637713509
8LockedQAM25679705000000 Hz-7.8 dBmV40.4 dBmV52517039
Connection Expert
EG
Posts: 43,084
Registered: ‎12-24-2003

Re: Frequent internet outage in Eastern MA

[ Edited ]

That's pretty weak but the SNR is good. Looks like it was made to be worse... Are you having any more "outages" ?

Regular Contributor
hongzhang
Posts: 48
Registered: ‎05-31-2012

Re: Frequent internet outage in Eastern MA

I have not noticed any outage.  If I understand it correctly, everything is within spec at least right now though not desirable. The biggest issue was the US power level.

Connection Expert
EG
Posts: 43,084
Registered: ‎12-24-2003

Re: Frequent internet outage in Eastern MA

If you are not having any more problems then it looks like you modem is able to cope with the weak downstream power. Be advised that now the downstream no doesn't have much wiggle room and that you *may* have a problem when the warmer Summer temperatures arrive as this will weaken the forward power even more.