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Connectivity and managing Your Comcast Business network
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LeeThompson
New Contributor

Local Problem with Hot Weather Conditions?

I've been tracking an issue while we've had some unusually warm weather in this area and comcast business modem & voice resetting simultaneously.

 

(This isn't really a truck roll moment, it's more of a "hey are you guys aware of this" thing)

 

If the temperature in this area (zip 98055) goes above 80F, there seem to be periodic resyncs/resets with the connections.   (I would hazard a guess that some of the equipment is in a non-temperature controlled room and eventually just starts wigging out).

 

A few things seem to support this theory:

1. I've been tracking outside temperature along with these (usually) brief outages

2. They seem to begin in the late afternoon (around 3pm ~ 4pm local time) when the temperature is near it's peak.

3. They continue, semi-randomly, until around midnight when it's really starting to cool down.

 

Some examples:

 

1. 2014-07-01 16:57 outside temp: 93F

2. 2014-07-01 20:55 outside temp: 83F

3. 2014-07-02 15:31 outside temp: 81F

4. 2014-07-02 15:55 outside temp: 81F

5. 2014-07-02 16:03 outside temp: 82F

6. 2014-07-02 20:03 outside temp: 76F

7. 2014-07-06 15:50 outside temp: 87F (this was an especially ugly one, didn't get sync back for 23 minutes)

 

Anyway you get the idea.

 

My home office here is air conditioned but air conditioning isn't very common in this area so I can totally see that maybe somewhere up the line something is overheating.   

 

There's also a lot of construction in this area so there could be some issues related to that too.

 

 

 

I believe the equipment and connection at the home office here is fine (and it's a 2012 install) but just have been noticing some possibly temperature related issues.

 

 

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9 REPLIES 9
Trusted Forum Contributor

Re: Local Problem with Hot Weather Conditions?

Temperature is something that generally only affects client side equipment as all server equipment is hosted in data centers which are kept extremely cold. 

 

Just a wild guess here, but it is possible that the heat is causing a specific section of cable to expand and compress which is causing some issues. Generally only damaged cable would have this issue, though, and I'd expect Comcast to be able to se that as it'd  be putting a lot of noise on the line.

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Trusted Forum Contributor

Re: Local Problem with Hot Weather Conditions?

kraze is right about the datacenter equipment, and it sounds like you're keeping your end's equipment cool enough. Think you could post your modem signal levels? I believe that higher temperatures cause upstream power levels to decrease and downstream power to increase, and they may be borderline in normal weather but drifting out of spec/out of ideal range when it's hot outside. You didn't mention your modem model, but you can find these signals generally by browsing to http://10.1.10.1, http://10.0.0.1, or http://192.168.100.1, or whichever IP address your modem has.

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LeeThompson
New Contributor

Re: Local Problem with Hot Weather Conditions?

Modem: SMC SMCD3G-CCR (Firmware 3.1.6.54)

 

Stats as of right now (connection is fine):

 

Outside Temp: 63F

 

Downstream Power: -4.363595 dBmV, -4.589916 dBmV, -4.245671 dBmV, -5.448189 dBmV

Upstream Power:  47.0000 dBmV, 48.5000 dBmV, 49.0000 dBmV, 48.5000 dBmV

 

Downstream SNR: 37.355988 dB, 36.844463 dB, 37.355988 dB, 37.092701 dB

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LeeThompson
New Contributor

Re: Local Problem with Hot Weather Conditions?

2014-07-08 13:00  

 

81F
downstream power: -5.396182 dBmV, -5.507679 dBmV, -5.218738 dBmV, -6.382004 dBmV
downstream SNR: 37.355988 dB, 36.844463 dB, 37.092701 dB, 36.844463 dB
upstream power: 47.0000 dBmV, 48.5000 dBmV, 49.0000 dBmV, 48.5000 dBmV

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Highlighted
LeeThompson
New Contributor

Re: Local Problem with Hot Weather Conditions?

Had the first outage issue of the day, but the numbers seem ok (?):

 

Outside temp at the time of the outage was around 86F.

 

Unfortunately I wasn't able to jump on the cablemodem during it but I did catch it 15 minutes after it stopped.

 

2014-07-08 15:22 (didn't route until 15:26)

2014-07-08 15:30 (didn't route until 15:33)

2014-07-08 15:37 (didn't route until 15:41)

2014-07-08 15:44 (didn't route until 15:45)

 

It recovered, eventualy, on it's own, usually when it does this "4 minute" pattern I have to power cycle it (off for 2m).

 

 

 

Modem Stats (shortly after event):

 

2014-07-08 16:00    modem: downstream power: -5.127232 dBmV, -5.203783 dBmV, -5.140637 dBmV , -6.127459 dBmV
2014-07-08 16:00    modem: downstream SNR: 37.355988 dB, 36.844463 dB, 37.092701 dB, 36.844463 dB
2014-07-08 16:00    modem: upstream power: 47.0000 dBmV, 48.5000 dBmV, 48.5000 dBmV, 48.5000 dBmV

 

 

Modem Stats Before (I knew I should've done a sample at 15:00):

 

2014-07-08 14:00    modem: downstream power: -5.147938 dBmV, -5.242950 dBmV, -5.159728 dBmV, -6.423411 dBmV
2014-07-08 14:00    modem: downstream SNR: 37.355988 dB, 36.844463 dB, 37.092701 dB, 36.844463 dB
2014-07-08 14:00    modem: upstream power: 47.0000 dBmV, 48.5000 dBmV, 49.0000 dBmV, 48.5000 dBmV

 

 

(Again this isn't really a truck roll thing as it doesn't do it all the time, seems to be more frequent when it's really warm outside, like today.   I'm mostly just curious what the heck is going on with it.)

 

What's the optimal baseline for power and SNR?

 

 

 

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LeeThompson
New Contributor

Re: Local Problem with Hot Weather Conditions?

Just had another one and this time, I got better info:

 

2014-07-07 16:23    start: alerter (couldn't ping gateway) (outside temp: 86F)
2014-07-08 16:23    modem: downstream power: -5.517918 dBmV, -5.546569 dBmV, -5.458819 dBmV, -6.550837 dBmV
2014-07-08 16:23    modem: downstream SNR: 37.355988 dB, 36.844463 dB, 37.092701 dB, 36.844463 dB
2014-07-08 16:23    modem: upstream power: 47.0000 dBmV (only channel 3)
2014-07-08 16:30    environment: 86F
2014-07-07 16:39    event: power cycle (unplug)
2014-07-07 16:42    event: power on
2014-07-07 16:44    event: connected
2014-07-07 16:45    end: online
2014-07-08 16:45    modem: downstream power: -5.070086 dBmV, -5.203783 dBmV, -4.964192 dBmV, -6.232115 dBmV
2014-07-08 16:45    modem: downstream SNR: 37.355988 dB, 36.844463 dB, 37.092701 dB, 36.844463 dB
2014-07-08 16:45    modem: upstream power: 47.5000 dBmV, 49.0000 dBmV, 49.0000 dBmV, 47.5000 dBmV

 

Downstream Frequencies: 597.001831 MHz, 578.998047 MHz, 584.999268 MHz, 591.000610 MHz
Upstream Frequencies:  18900000 Hz (Ch 3), 30100000 Hz (Ch 1), 36500000 Hz (Ch 2), 23700000 Hz (Ch 4)

 

During the outage I pinged the modem's static WAN gateway (73.98.96.1) and it was responding.  So it appears the outage is the loss of transmit ability.  (This particular one anyway).

 

(Note the delay with power cycling etc was so I could poke around the modem admin and write stuff down.  I'm normally much more responsive than that Smiley Wink)

 

During the outage the first three modem lights (other than power) from left to right were all steady on, it basically thought it was connected but wasn't transmitting until I power cycled it.

 

 

 

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Trusted Forum Contributor

Re: Local Problem with Hot Weather Conditions?

Your upstream signal seems to be too high. At 50 you could start seeing issues and it's possible it's dipping out of spec at certain parts of the day. Have you had a tech out at all?

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Trusted Forum Contributor

Re: Local Problem with Hot Weather Conditions?

bah and i had it flipped, upstream power tends to RISE in high temperature. yes this could be it

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LeeThompson
New Contributor

Re: Local Problem with Hot Weather Conditions?

(Edit: Why are Rich Text  & HTML edit here when they don't work correctly?)

 

The thing I don't get, is we have comcast business in other locations (granted the modems aren't the same) and the "correct range" downstream/upstream power seems to vary.

 

For Example:

 

Site A: (Netgear 1.04)

Downstream Channel

Downstream Frequency555000000 Hz561000000 Hz567000000 Hz573000000 Hz579000000 Hz585000000 Hz591000000 Hz597000000 Hz
Lock StatusLockedLockedLockedLockedLockedLockedLockedLocked
Modulation256 QAM256 QAM256 QAM256 QAM256 QAM256 QAM256 QAM256 QAM
Symbol Rate5.360537 Msym/sec5.360537 Msym/sec5.360537 Msym/sec5.360537 Msym/sec5.360537 Msym/sec5.360537 Msym/sec5.360537 Msym/sec5.360537 Msym/sec
Downstream Power-3.7 dBmV-3.7 dBmV-3.7 dBmV-3.9 dBmV-3.9 dBmV-3.6 dBmV-3.7 dBmV-3.8 dBmV
SNR40.3 dBmV40.3 dBmV40.1 dBmV39.9 dBmV39.9 dBmV40.1 dBmV39.9 dBmV39.9 dBmV

Upstream Channel

Upstream Frequency30100000 Hz36500000 Hz18900000 Hz23700000 Hz
Lock StatusLockedLockedLockedLocked
ModulationATDMAATDMAATDMAATDMA
Symbol Rate5120 sym/sec5120 sym/sec2560 sym/sec5120 sym/sec
Upstream Power51.0 dBmV51.0 dBmV51.0 dBmV51.0 dBmV

 

The upstream is over 50 dBmv and oddly I've never seen it change from 51.   No problems either.

I do notice the modulation is different.

 

 

Other Location:

 

Vendor NameSMC Networks
Hardware Version

1B

Downstream Channel

Downstream Frequency639000000 Hz
Lock StatusLocked
Modulation256 QAM
Symbol Rate5.360537 Msym/sec
Downstream Power-7.3 dBmV
SNR36.742 dB

Upstream Channel

Upstream Frequency30100000 Hz
Lock StatusLocked
Modulation64QAM
Symbol Rate5120000 sym/sec
Upstream Power47.1 dBmV
Channel ID1

 

 

So for me, it seems fairly inconclusive.    I've been checking my values here much more often and I do believe direct sunlight with higher temperatures (85+)  is having some kind of effect but it's not consistent at all.

 

(I had it flip here when a minute before all 4 upstream power's were under 50 dBmv.)

 

 

And again, this is primarily an intellectual exercise, it isn't annoying enough for a truck roll or anything, it's just weird.

 

What is annoying this new issue:

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