Modem and router show radically different data use

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  • Updated 3 years ago
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I have a Exede supplied modem (?Surfboard?) connected to a TP-Link wireless router (WR841ND) at a second home. 

I track both satellite data usage (with the Exede usage meter) and local WAN traffic on the router down to the MAC address level.

The problem I am having difficulty resolving is that that the numbers I am seeing don't agree. Exede is reporting much high data use than the local area network says it is sending or receiving.

Assuming both sets of numbers are correct, this leads me to believe that at least one of the following situations is occurring:

(1) The satellite-modem link is very chatty- maybe slight misalignment causing numerous resends?
(2) Large amounts of data is being sent to and from the satellite modem for updates?
(3) The exede "voice" telephony box that sits between the modem and the router is somehow doing something to force multiple resends of data from the satellite.
(4) The modem keeps sending packets to the router that aren't being accepted for some reason resulting in lots of resends.

My plan 
(1) Look at the status logs of the modem and see what it says is going on. If this isn't obvious then
(2) Power down the modem  and phone box for 24 hours and see if the data usage on the exede site continues to change. If it does it is a satellite/modem issue.
(3) Hook up the phone for 24 hours and check data usage again. Usage should not change since the phone isn't supposed to subject to the data cap. If it is then it is a satellite modem/voice issue.
(4) Then repower up the router and monitor usage on both the local network and the exede side during a 100MB upload and download. to check 

Needless to say this is not convenient.

Am I missing something?
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Andrew Cary

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Posted 4 years ago

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Photo of JEP


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Andrew - If you want to get an accurate measurement of data usage while your modem is powered down, you must check your usage with an Internet connection other than Exede.  Check the usage from work or a WiFi hot spot like McDonalds.  Latent data usage can be stored in the modem that will be reported on power up and a connection starved computer can gobble up many Mb before you even get control of the desktop.
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Andrew Cary

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I was trapping data usage statistics on my local wifi/hub locally and remotely (not using the Exede satelite modem) by device MAC address.  I was able to very clearly see utilization by device over time in the local network.  I was able to correlate the local usage with modem traffic by hour using the eSVT interface and a 3rd party tool called Satellite Restriction Tracker. Both eSVT and Satellite tracker cannot identify devices on the local wifi network, but they can give me the total consumption.... 

Here is what I observed, there are periodic bursts of data transmission from the satellite that appear to be unsolicited by the devices on the local network. These are not large amounts of data (MB not GB) and occur maybe once or twice a cycle. I can live with this.

I was able to identify that much of my mysterious data usgae was not mysterious at all, but a Windows 10 computer that was backing itself up to the cloud without the user's knowledge every time they signed on to the local wifi. The user set the device to only synchronize during the unmetered zone after midnight and data utilization now behaves more or less as expected.

The ironic thing is that several months later the user replaced another old PC they had and remembered to carefully set the synchronization to occur after midnight. Unfortunately the device decided to back not only the new data, but the user's entire data storage. this ran until midday the following day and consumed the entire months data allotment on the first day of the billing period. (Sigh).

The next step will be to load Gargoyle on the local wifi switch --  It is a tool that supports quota throttling on the local network.   That will allow me to control how much each device gets and throttle the device down to very slow speeds when it uses up its quota.  
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Thanks for keeping us updated Andrew.  This will help many people.