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Apologize if I am not very technical, but networking is not my field of expertise. I work at a positioning system service. We collect data from GPS satellites via GPS antennas in the field, get the data from the antennas, calculate X,Y,Z coordinates in our servers, and distribute accurate coordinates to GPS users in the field via the mobile GPRS network. We have 5 servers here. Three collect data from the antennas, and the other (NTRIP server) distributes them to the users.

Now, we are having network interruptions during certain hours of the day (8 AM to 18 PM approximately, Monday to Friday). In the evening and during the night, everything works fine.

Our internet provider confirmed that everything is fine on their end. It seems there is a problem with the communication among our servers. If you try to ping one server from the other through the CMD, we would get a request time out for every 20 successful replies. The timeouts are random. The servers are inside the Active Directory. Windows Server 2008 R2 is installed in all the servers.

We have had some IT specialists have a look at our system, but they haven't been able to get the reason why this is happening. So, I desperately came to ask here. Please feel free to edit my question. Any tip would be great.

Edits: I myself tried restarting the servers, the switch, the modem and the router, but nothing changed. I am providing the network topology here:

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The active directory domain is located at Control Center server. The Datastorage, Network are used to calculate the coordinates collected from 16 GPS reference stations. The coordinates are stored in the Datastorage server. The RTCD-Admin holds the Microsoft SQL database. Ignore the the RINEX, and the Transformation server from the topology. They don't have any role anymore. The NTRIP server gets the data from the Datastorage server and distrubutes it to the users. We give the users the public IP of the NTRIP server, the port, the username and the password. They enter these data in their GPS receivers and get real time coordinates via GPRS internet. This installation was an existing one, and we don't understand why the problem appeared. The user traffic has not increased. Indeed, we have very few users we distribute data to.

Updates following the suggestions, I isolated the problem. It came out that when the router was disconnected from the switch, the communication between the servers was normailzed (no request timed out anymore). Now, I am trying to understand whether that is a problem with the router or the modem, and wheather the problem is physical or it has to do with the configurations.

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  • Please consider adding more details – Mike Pennington Feb 19 '15 at 8:38
  • If you can reproduce the issue at will, get a simultaneous packet capture on every device, reproduce the issue and you'll see where the packets are dropped. – Pedro Perez Feb 20 '15 at 0:17
  • 18am? Also consider scheduled tasks like backups, configuration syncs, etc. – cpt_fink Feb 20 '15 at 8:05
  • Ok, I tried to isolate the problem, and I updated my question with the results. – multigoodverse Mar 26 '15 at 13:42
  • Did any answer help you? if so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer. – Ron Maupin♦ Aug 11 '17 at 4:18
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You have to try and isolate the problem as much as possible. Need to work out exactly which communication stream drops out. Do this by testing connections between all isolated parts of the network, that is computer one - > computer two, computer three - >computer four. Once you have narrowed down the problem it will be a lot easier to fix.

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