Question Regarding Mobile Data Billing

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bdiesel

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Hi All,

I have a question regarding how mobile data gets billed. Is it billed as the data attempted to be sent from the device (so any re-transmits are billed for), or is it billed for packets that are successfully sent?

I am analysing the data situation on modems and looking at it from the device side, there is significantly more data that is attempted to be sent, than is actually received on our servers. Can anyone point me to information as to how this data gets billed?

Bruce
 
bdiesel said:
I have a question regarding how mobile data gets billed. Is it billed as the data attempted to be sent from the device (so any re-transmits are billed for), or is it billed for packets that are successfully sent?
Click to expand...
Data is billed from the base station side, so you will be billed for data that was sent to your device, regardless of whether it was received or not, as well as any transmit retries. You will also be billed for data that is received from your device, but not for data that was sent by your device and not received at the base station.
bdiesel said:
I am analysing the data situation on modems and looking at it from the device side, there is significantly more data that is attempted to be sent, than is actually received on our servers. Can anyone point me to information as to how this data gets billed?
Click to expand...
I recall an article, I think written in the UK, about how poor signal, and thus many retries, can significantly increase your bill. If I find it, I'll post a link.
 
Thanks for the reply ginggs. I guess the next question is, what are the chances that data received by the base station is dropped further up the chain?

I have a situation where billing data is being generated from the modem, but I don't see that data at my server. Where the packet actually gets dropped become significant then!
 
I had no problems with overcharging for data with Vodacom, Cell C or 8ta. There are always consistent with modem statistics. However there are two factors you should be aware.

1. Number of lost packets or erroneous (rejected) packets which leads to retransmission requests, TCP transmit window (or UDP streaming) and cancelled requests. It will show difference between modem statistics and actual downloaded data. Due to the dynamic routing, TCP/IP packets come using different routes, sometime duplicated. All it counts for data usage. I suspect that the biggest difference will generate UDP data streaming (watching movies or VOIP), as single request can generate large number of incoming number of packets.
Note that above should not be mistaken with packet lost between tower and mobile device; these are detected at radio-link layer, retransmitted and not counted by the service provider.

2. If your device is losing data connection and is set to automatically reconnect (you might not notice that with many smartphones or 3G routers). By example B683 in default settings will zero statistics and reconnect. Next time you check, it will be a difference. I always set B683 to manual mode; when it loses connection, I know that statistics are lost... :-(
In addition every reconnect involves minimum data charge, you should be aware of.
 
sajunky said:
I had no problems with overcharging for data with Vodacom, Cell C or 8ta. There are always consistent with modem statistics. However there are two factors you should be aware.

1. Number of lost packets or erroneous (rejected) packets which leads to retransmission requests, TCP transmit window (or UDP streaming) and cancelled requests. It will show difference between modem statistics and actual downloaded data. Due to the dynamic routing, TCP/IP packets come using different routes, sometime duplicated. All it counts for data usage. I suspect that the biggest difference will generate UDP data streaming (watching movies or VOIP), as single request can generate large number of incoming number of packets.
Note that above should not be mistaken with packet lost between tower and mobile device; these are detected at radio-link layer, retransmitted and not counted by the service provider.

2. If your device is losing data connection and is set to automatically reconnect (you might not notice that with many smartphones or 3G routers). By example B683 in default settings will zero statistics and reconnect. Next time you check, it will be a difference. I always set B683 to manual mode; when it loses connection, I know that statistics are lost... :-(
In addition every reconnect involves minimum data charge, you should be aware of.
Click to expand...

In my case the data is originating from the device and being sent to my servers. Modem stats show a lot more data sent than my line graphs on the pipe coming in to my server. Running a wireshark trace on the device side, we see tons of retransmits. I assume the packets are dropped between the modem and the tower. If this is the case, should I get billed for these dropped packets? I have limited understanding of GSM networks, but from what I have been able to ascertain, the Chargable Data Records are only generated further up the chain. In which case, using modem logs would not be an accurate source of billing information.
 
bdiesel said:
Modem stats show a lot more data sent than my line graphs on the pipe coming in to my server. Running a wireshark trace on the device side, we see tons of retransmits. I assume the packets are dropped between the modem and the tower. If this is the case, should I get billed for these dropped packets?
Click to expand...
In my opinion you will be not charged for lost packets between modem and tower. Modem statistics will show inflated number comparing to your actual bill. It happens to me regularly. Difference is from 5% to as much as 20%.

Change modem to see if any difference, use short USB cable - your modem might run on limited transmission power due to the insufficient power delivered from USB port.
 
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