Looks like no one’s replied in a while. To start the conversation again, simply ask a new question.

Mobile Data Usage Accuracy

Hello,

I recently did a carrier switch and the new carrier reports way higher data usage that I'm used to.

I usually never checked the mobile data usage in the settings, so I don't have any experience on how accurate it usually is. I always had 3GB included and reached approx. 1-2GB maximum.


So, I recently reset the statistics to compare the unusual high figures reported by the carrier and it turns out:

My phone shows 40MB data transfer while my carrier bills me 300MB transfer!!!


I asked the carrier and they said that their figures are correct and their counts are what matter. They also told me, that I should give up comparing it to the mobile data usage reported by my phone as this is not accurate at all.


I'm aware that there are some circumstances why the carrier figures are higher, e.g. their billing rounds up to the next full 64kB, transmission errors that cause resends etc. I would expect 10% higher figures, or maybe 20% higher, but in my case it's nearly tenfold!


Has anyone experienced something like this before or knows how to solve this? How much off are the statistics for you?


Best Regards

iPhone 6s, iOS 9.2.1

Posted on Feb 1, 2016 12:23 PM

Reply
15 replies

Feb 5, 2016 1:25 PM in response to Philly_Phan

Yeah, I've that feeling too...

I also posted my problem in a carrier related forum and at least one user there experienced the same problem. For him this issue started after activating a free 1GB LTE test package (christmas goodie) and remained after this package expired... I switched exactly at that time and also activated that free package, so I have no comparison with how this was before...


Luckily it's all prepaid, so switching again is easy... I already bought a prepaid sim from another carrier and will try that for a time. If it's OK there and the other carrier cannot (does not want to) solve it I just need to transfer my phone number...


How much off is the statistics from you phone(s) typically. I know that the mobile data usage displayed and billed differs, but I just want to get a feeling about how much it is on average...


Best Regards

Feb 5, 2016 1:32 PM in response to Philly_Phan

The actual answer is "it's complicated". Your phone is not likely to be that accurate, but your new carrier is for sure doing something different. Keep this in mind, The carrier software that measures data usage is really, really accurate. The phone, less so. There is a lot to the concept of measuring data usage and there is a lot of work that goes in to developing the software.


Having said that, I have a suspicion that you are seeing a different due to the granularity of measurement. Some carriers uses, for example, a 64KB chunk to measure data usage, meaning if you trigger a 1KB data pull (something really small), the carrier counts 64KB usage. If this legal? Sure it is, it's not actually wrong. Even your hard drive on your PC does this (ever see the setting for hard drive block size?) All software rounds up, its just a question of how it rounds up. I suspect that you are pulling rather small data payloads and your new carrier is using a larger block size than your old one.


Now this isn't easy to change for a carrier as any changes will have massive influence over the entire system. I wont go in to details, but if the change is not well thought out, it will for sure wreak havoc on the carrier. I am not sure who your new carrier is, but you can certainly ask them. The customer rep won't know, but someone will 🙂. Good luck!

Feb 5, 2016 2:08 PM in response to allenfromalpharetta43

My carrier rounds to 64kB, but that seems not to be the problem.

the connections usually last 1-2 hours and transfer a few - or several hundred - MB.


I also read about android updates causing 1kB transfers and dropping the connection afterwards, and this happens every few seconds. This is usually the scenario where the 64kB rounding hits you hard, but not in my case.


i would guess that the two statistics could be off 10-20% with good reception and worse if bad reception and connection drops happen. But i have no experience with it...


thanks for your help

best regards

Feb 5, 2016 4:29 PM in response to kuetsch

Your reply was a bit confusing. But in general, a 9 hour session is incredibly long and not normal. The tower won't keep a session open that long unless there is something generating traffic on the line to keep it open. This would also burn battery power like crazy since the LTE chipset needs to be kept on the whole time. I recommend looking at the detailed billing to see how long your sessions are. If there are super long sessions like in the range of hours, you have something keeping the link alive and those are counted as data usage, even if the phone doesn't record them as such.

Feb 7, 2016 8:53 AM in response to allenfromalpharetta43

Hi,

please correct me, if I'm wrong, but my understanding was always that the connections are kept open without the need for alive packets.


AFAIK Wifi needs these alive packets and therefor drains the battery when active.

Cellular connections are however designed to not need alive packets. Instead they just assume the telephone is there until it logs onto some other station when the telephone thinks that reception is better somewhere else.

E.g. Airplane Mode does not log off the telephone. I once had sth. changed by the carrier and Airplane mode did not help with propagating the change. I called the carrier and they said I have to restart the phone s.t. it newly logs in to the station. (Taking out the SIM and putting it in again would probably also have done the trick)

And also now, when turning on airplane mode this does not affect the connection duration on the detailed billing data. Only switching off and on will terminate the connection.

Also I already read that the iPhone actually drops the Wifi connection during standby and uses the cellular connection for notifications because of this difference.


The connection times are from the detailed billing, but for all connections with less than 3MB transfer there are no durations mentioned. However I also assume that these connections are about 1-1.5h long as they appear in the same rhythm.


Anyway, the long connections are not the issue, IMO it's ok if the connection is held 1.5h and only 2MB are transferred for e.g. iCloud Sync, checking eMail, getting Notifications etc. This would be the expected behaviour. And it's also OK, if I or my telephone uses more data for whatever reason (watching video, browsing the web etc)


The only questions is, how can it be that the mobile data usage shown and billed differ by THAT much. If my phone shows 20MB and my carrier bills me 30MB I would still say that this is plausible. If they however bill my 300MB I would say that either my telephone or my carrier have gone crazy and one does not tell the truth.


How do the statistics compare for you?


Best Regards

Feb 7, 2016 9:52 AM in response to kuetsch

So all good questions...


- I did a quick check on my account vs my phone and it's not too far off as near as I can tell. The phone is showing last 30 days, the unbilled usage is just for the last 5 (billing cycle just ended). The phone is probably 10% lower, which is about what I would expect.


- Airplane mode turns off all chipsets that can transmit a signal, so you are not "alive" to a tower. Your LTE chipset is powered down to reduce battery consumption. The same is true for your wifi connections. Shutting the transmitters saves power, a lot of it 🙂.


- i think we are talking about two different things in terms of sessions. To keep any IP data session active continuously, you need keep alives. These keep alives are artificial packets. That is, they are not sent unless something is specifically telling it to do so.


- A cell tower will cut off the session once the data transfer is completed. This keeps the tower capacity from being overtaxed. It is also the trigger for the tower to send a billing record over to the billing system for data charges.


- When your cell phone is on, it "reads" the local, towers that are near it and based on an internal algorithm, it decides which tower is the one it wants to use. There is a "registration" process for this and at that point you are tied to a single tower. When you are ready to transmit, you then get an IP session and the billing starts. Once your IP session closes, the data used sent to the data rating system.


So having said all of that, my phone bill shows the amount of data transferred in KB and the time the usage was billed. This is roughly corresponding the times that I am on the LTE network and doing something. It's not super granular in a sense, but you can look on your bill and see how it is charged. Assuming the billing details are like mine, then would see either lots of smaller data transfers or a few really, really big ones. If its the former, it means there is something(s) kicking on and syncing stuff all the time. If it's the latter, it means there is something keeping the session alive and just sucking data continuously. This would have to be almost constant since the after a couple of min, the IP session will be terminated for inactivity.

Feb 7, 2016 9:51 AM in response to allenfromalpharetta43

Ok, so at this point I just assume that there is a connection alive for push notifications.

It might cause some data, but I also should show up in my phones statistic. And this is exactly not the case.


For you the statistics fit, 10% difference is a value I would expect too. I also read that it should be quite accurate and is only off by rounding and bad reception resends and such things.


I already read about others having similar problems with this particular carrier, so I would assume that it's not an iPhone related problem.


Best regards

Feb 7, 2016 11:21 AM in response to kuetsch

Yea I would expect about 10%. Mostly because of some rounding differences. Bad packet retransmits are a big no no 🙂. Normally, bad packets should be a small fraction of a percent.


It does sound to me like the carrier software is doing something odd. It could be rounding very differently than what they are telling you or they are tracking sessions in a weird way or even cross multiple phones in one account. I would for sure get more information from them. A keep alive signal is really small and does not need to be sent that often. I am bummed that you are having issues, but good luck with the carrier!

Feb 9, 2016 12:25 PM in response to allenfromalpharetta43

Hi,

I watched the stats for the last few days and currently the transfers billed are about 12% higher than the ones recorded by the phone.

Maybe this was a temporary issue and they just don't acknowledge that they had a problem. We'll see...


Luckily it's a prepaid SIM card, so I can easily try another prepaid SIM card and transferring the phone number isn't that costly.


Thanks again for confirming my initial gut feeling that the stats should be ~10% off


Best Regards

Mobile Data Usage Accuracy

Welcome to Apple Support Community
A forum where Apple customers help each other with their products. Get started with your Apple ID.