[ANSS-netops] cell modems and first of the month

Sat Dec 3 00:17:55 UTC 2011

Hi Philip,

We had a couple of years ago when we started using cell modems seen a consistent daily reset of our telemetry on the Verizon network with static IP addresses, every day around the same time. We stream data from Q330 dataloggers so we don't loose data since there is a buffer but it was very irritating and caused us great angst. In our initial deployments with DIGI Connectport WAN modems the connection would recover most times but we would sometimes loose connection for 24 hours and sometimes until a field person was sent out. So we decided to retrofit those locations with a daily reset timer. Yeah, yeah, we went though all the regular trouble-shooting routines, like setting up the modem to check for connection to server, talking with DIGI, dealing with Verizon ... nothing worked. The timer was drastic but better than sending a field tech out just to reset the cell modem.

Since that initial deployment, we have moved to Raven X and have had better luck. We still see an occasional daily reset and once a station starts seeing it, the daily reset goes on for a week to 10 days. But we haven't had a Raven X lock up on us yet.

In some of our previous conversations with Verizon technicians troubleshooting this problem they had mentioned that Verizon billing/accounting has to tally the amount of data usage and in order to do that they have to momentarily drop the connection between the cell tower and the cell modems.

Recently we ran some tests on the SPRINT network and Raven X cell modems and we did not see the daily reset pattern.

cheers,
rayo

__________________________________________

Rayomand Bhadha       rayo at gps.caltech.edu
Caltech Seismo Lab   phone: (626) 395-2407
Pasadena, CA          cell: (626) 298-9809
__________________________________________

On 12/2/2011 11:06 AM, David S. Croker wrote:
> Philip,
>
> I don't think I have much to add. We don't see a pattern in drop outs, and certainly don't have to recycle power on our modems very often. I know your pain and concern, however, as we also hate it when a costly maintenance trip is only to recycle the modem or RT130. Note that we still only have Verizon modems at this point, and only a handful.
>
> I do have to say that we have varying degrees of success with cell modems so far. Some seem solid and others experience more drop outs. We've compared RSSI and EC/IO numbers (thanks to someone at Feeney and Mark Meremonte) and don't see much correlation, including the fact that the one site that probably has the lowest RSSI also has the most complete data. I would love to be able to plot traffic at a particular cell site versus data drop outs. In other words, cell modems are still generally qualify as a last resort for our data telemetry needs.
>
> Sorry I couldn't be more help.
>
> Dave
>
> At 09:36 AM 12/2/2011, Support wrote:
>> Content-Type: multipart/related;
>>
>> boundary="_005_33C2C86F559D98498A36C5C2536FEFEAC2CEA42AFeeneyDC1feeney_";
>> type="multipart/alternative"
>> Content-Language: en-US
>>
>> No, The modems don’t require a daily resetting of the devices. An occasional power-cycling of the modem wouldn’t hurt but should not be required. If you are having occasional issues with the strength of the signal (RSSI – Receive Signal Strength Indicator being low (higher negative value)), then we would need to determine what the issue is one a case-by-case basis. You also want to watch the EC/IO (a measure of energy (interference)) as well. A directional antenna should provide a better signal. Whether the device has to be reset depends on its recovery once the connection has been re-established.
>>
>> One other thing to watch is the modem and device firmware. Make sure it is kept current. This also helps.
>>
>> Thanks,
>>
>> Roger K. Parker
>> Engineering Technician
>> <mailto:rparker at feeneywireless.com>rparker at feeneywireless.com
>> Feeney Wireless, LLC - 4085 W. 11th Ave. Unit #3, Eugene, Oregon 97402
>> (Free) 800-683-4818
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>> From: Mark E. Meremonte [mailto:meremonte at usgs.gov]
>> Sent: Friday, December 02, 2011 8:59 AM
>> To: Philip Crotwell; anss-netops at geohazards.usgs.gov
>> Subject: Re: [ANSS-netops] cell modems and first of the month
>>
>> HI Phillip,
>>
>> Is it a requirement to daily power cycle a Raven-X, XT, XE if using Verizon service? I have numerous Cell modems across the country now and have never power cycled them. However, I do have a couple that had weak to nill signal strength from time to time; and 2 which the RT130 would not renegotiate to the Internet. Thus the RT130 had to be physically power cycled after I installed a directional antenna vs an Omni to obtain a more robust signal from one cell tower instead of 2 or more which the Omni appeared to be jumping around.
>>
>> Mark
>>
>>
>> At 07:54 12/2/2011, Philip Crotwell wrote:
>>
>> Hi all
>>
>> We use raven-x cell modems on both verizon and at&t and have noticed
>> that often a large percentage of the stations will go offline shortly
>> after midnight on the first of the month. Not always, and not exactly
>> at midnight, but usually between midnight and 2am. Usually the
>> stations come back after our daily cell modem power cycle. It seems to
>> happen more often with Verizon, but has also happened with AT&T. Tech
>> support is as usual completely useless as they suggest "turn off the
>> power and turn it back on again" and seem very surprised when I tell
>> them I can't.
>>
>> Has anyone else seen this odd behavior? Any words of advice?
>>
>> thanks,
>> Philip
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>>
>> U.S. Geological Survey: Geologic Hazards Science Center
>> Denver Federal Center Work: 303-273-8670 Cell: 303-478-5766
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