Increased cellular data use may be linked to streaming bug in iOS 6.0

Increased cellular data use may be linked to streaming bug in iOS 6, fixed in iOS 6.0.1

A bug in Apple's AV Foundation framework, which handles streaming audio and other media for podcast apps, radio apps, and more, could be behind the mysterious, maddening cellular data spikes many users, myself included, have experienced since updating to iOS 6 or the iPhone 5. In essence, iOS just keeps on downloading data, over and over and over and over again, sometimes gigabytes worth at a time. Here's what PRX Labs found after doing some research into it:

The player appears to get into a state where it makes multiple requests per second and closes them rapidly. Because the ranges of these requests seem to overlap and the requests themselves each carry some overhead, this causes a single download of an MP3 to use significantly more bandwidth than in iOS 5. In one case, the playback of a single 30MB episode caused the transfer of over 100MB of data.

PRX was testing Wi-Fi, but seem to believe cellular, including LTE, would exhibit the same bad behavior. PRX also believes the bug is fixed in iOS 6.0.1, though Matthew Panzarino of The Next Web points out that some believe they're still seeing the bug even after updating.

iMore has had complaints about video podcasts taking longer to download than usual as well, and while it's unknown if the issues are related, it's also impossible to rule them out.

Let's be clear though, this is an issue that is costing real people real money. I've never before gotten close to my $35/6GB data plan limit before, yet last month I blew past it far enough to be surcharged $50. All I do is stream audio, and I haven't been streaming anything different than I used it. Less in fact.

If this isn't fixed already, it needs to be fixed immediately.

Source: PRX Labs via The Next Web

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Rene Ritchie

EiC of iMore, EP of Mobile Nations, Apple analyst, co-host of Debug, Iterate, Vector, Review, and MacBreak Weekly podcasts. Cook, grappler, photon wrangler. Follow him on Twitter and Google+.

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Reader comments

Increased cellular data use may be linked to streaming bug in iOS 6.0


One thing that can cause tons of data transfer is Photo Stream. I sometimes shoot several GB of photos, then load them into iPhoto. It can take quite a long time to move 1000 photos to iCloud. (I think 1000 is the limit for Photo Stream.) Especially when they're full-resolution .NEF files.

Last month was the first time I have ever gone over my 500mb cap. Still not sure what happened but I used 1.2gb somehow. I don't think it was due to this podcast issue however.

After updating to 6.0.1 me and my wife were able to use 40% of our 2GB in half a day. All we used was the GPS for probably less than 10 miles.
We would never get close to 2GB when we had other smartphones. Apple needs to figure something out because I'm scared of using all the features of my phone.

Ouch....well, I crashed through 5GB very quickly after getting the iPhone 5. I thought it was because I was spoiled by the blazing fast LTE. This could be the culprit. Luckily, I have an unlimited data plan, but AT&T did threaten to throttle me if I crash through 5GB again!!!

Same here. I've never come anywhere close to 5 gb but somehow I blew through more than 5 gb in about two weeks. I also got a warning from AT&T. Hope Apple addresses this quickly.

I've noticed this issue with iHeart Radio lately. Their boards claim it's an apple issue but many users say this is the only app they have problems with. I also use pandora but haven't had this issue with pandora, only iHeart radio.
After reading this I think it's an iOS issue that needs to get fixed ASAP.

Yes, that is also my situation. From iPhone 4 to iPhone 5, same apps and usage. I have never been over 2.5 gig and the first month I had an iPhone 5 I went over 6 gig..I mostly stream music from Pandora and SiriusXM. Thankfully I'm still holding on to the unlimited ATT plan. I was expecting a serious throttle. After updating to 6.0.1 my usage has returned to iPhone 4 territory.

I agree! the only app heavy on data that i use is viber, i've been using it normally as before having the iphone 5. Previously I was able to go the month without getting closer to my 3gb cap. Now I have two months paying overcharge.

I picked up an iPhone 5 after several android phones over the years and in the 6 days of my plan i had blown past my 2gb limit and had to up to 7gb plan to compensate. Total malarky... My data usage has slowed to a tenth of that after the update to 6.0.1 so now Im now enjoying my LTE and this super smooth phone.

I took out my contract 2 years ago with only a 750mb data allowance, never used all of it and if I did I would go to about 800mb max. Since upgrading to iOS6 I regularly exceed my data. I have had to buy a bolt on to give me a total of 1.25gb, but I still going over that. All I do on my phone is surf the web and social networking. Kind of annoying.

I took out my contract 2 years ago with only a 750mb data allowance, never used all of it and if I did I would go to about 800mb max. Since upgrading to iOS6 I regularly exceed my data. I have had to buy a bolt on to give me a total of 1.25gb, but I still going over that. All I do on my phone is surf the web and social networking. Kind of annoying.

I have this happening on my totally updated iPad 2. I have never come close to my 2 gb allowance before and received a message a few days ago that I had used 65%. I turned off my cellular data immediately. I almost never stream on my iPad. I have unlimited on my iPhone 5 so if I want to stream, I do it on it. I called AT&T and the support person I talked to didn't seem to be aware of the problem. I made her google it. She told me to go to System Services under location services and turn off Diagnostics & Usage. I did that as well as turned off Genius (I had iAds off already). I also turned off my photo stream but even after all of that, when I turned my cellular back on and went back to usage, data had been sent and received while I was on wifi. I am not techie enough to know what is normal and do NOT want to go over my allowance so will wait until the month end, reset my usage and turn my cellular back on to try again unless I read there is a fix. Apple, please get on this! I hope my info is helpful.

I don't think this is "only" due to a streaming bug. My friend has an iPhone 4 on O2 in the UK. She's a very light user, never streams anything and only has a handful of apps installed, but after she updated to iOS6 her battery drained within hours, even when she wasn't using the phone. We deleted all her apps, deleted and reinstalled her email account from scratch and deleted her bookmarks as some people had reported battery drain due to corrupt bookmarks trying to sync via iCloud. Nothing helped. The battery drain only stopped when the phone was in airplane mode or when cellular data was switched off. This was both on 3G (we don't have LTE on O2 in the UK) and on WiFi. We checked the usage on her phone and could see cellular data ticking up by the second. O2 confirmed that in 1 week on iOS6 she had used 4 times more data than previously in a full month.

We did some research and the issue seems to be two-fold. Firstly, iCloud seems to consume more data under iOS6 than under iOS5 (this was causing my friend's battery drain). Secondly, under iOS6 cellular data is used to supplement WiFi (so even when the phone was on WiFi the drain continued) and the only way to toggle this is by manually switching cellular on/off. Deleting iCloud from the phone helps to stem the data leak, but doesn't address the issue of cellular data being used on WiFi.

There appears to be no reliable fix, so an Apple genius exchanged my friend's phone for a refurbished that was still on iOS5. She set it up as new, reinstalled her few apps and hasn't had any problems since.

I hope this experience is helpful to others who have this problem. :)

I've had no problems when I upgraded to iOS6.

Maybe you've got the wifi/cellular function on where it switches to cellular if its faster than wifi...maybe you forgot about that feature?

I got dinged for 9.5 GB of usage last month (just within my plan's cap). Prior to my iPhone 5/iOS 6, I never exceeded 5 GB. If I got close, that would be a really heavy month for me. I stream music/podcasts regularly, but my habits haven't changed since I got the new phone. And CERTAINLY not to the extent that I would have doubled my usage.

This issue needs to be addressed soon. And when it is, customers should be reimbursed for the data they were charged for but didn't use.

Two issues that I believe have impacted this for me are:

1. Enabling Cellular downloads for Podcasts, combined with the recently fixed (supposedly) Podcasts bug where old episodes would become marked unread and thus potentially be downloaded multiple times.

2. Netflix streaming on LTE uses 1GB/hour or more, at least on the iPad. I think it isn't quite so much on the iPhone, but it's in the ballpark. On 3G, I think it's more like 200MB/hour.

I've disabled Cellular downloads for Podcasts and typically avoid streaming them as well. Moreover, I've taken to disabling LTE if I'm going to stream video without WiFi. With these changes, my usage appears to be more in line with my history, though still somewhat higher.

I'm with you. Not sure it is just the API issue. I think that most sites that stream, especially video, check your speed. Faster speeds get higher quality. That has to be at least part of the issue.

With you on that. Sprint is a Godsend. No data limits and no throttling. It's not LTE and LTE won't be widely available for a while on Sprint, but it's good to not have to monitor data usage for overages.

Interesting. I had noticed increased battery usage, even though my usage patterns haven't changed since iOS6. iOS 6.01 seems to have stemmed the tied, but then, I'm on a 4S still, so hopefully, that's the end of it.

Strange, I live in Qatar, using Vodafone Qatar. I get 1.75GB to use every month and I only used about 200 to 300MB last month which is the same like every month since I got the iPhone 4S. I am on 6.0.1 already.

*Don't ask me why I pay for 1.75GB when I only use 300MB. I don't. They come as a free bonus with my voice plan.

This sounds like the bug I reported to Apple prior to release of the 6.0 GM. My 1 GB a month Verizon plan suddenly ran out of data while streaming video from TWiT. At the time I was connected to WiFi not Cellular according to the device. I had briefly been connected to cellular while I was outside but then returned to my house and the device switched back automatically to WiFi. It appears that the cellular connection was also left active and downloaded 1 GB of data over the next hour. I actually got the out of data message while connected to WiFi. This may be related to a feature Apple was going to add to iOS but later pulled which causes iOS devices to switch to cellular data when WiFi cannot connect to the internet (like when your home internet connection is down even though your WiFi router is still working). This feature allows you to move smoothly between WiFi and cellular data without skipping a beat when streaming. It's a nice feature but not when it sucks your monthly data without warning. Since I ran into this bug, I have been manually turning off cellular data when I don't want it. I suggest that everyone does the same until this bug is fixed.

ah this is probably why for the past couple of months i got a message from o2 saying that i had used all my data by the 2nd of the month for several months and now i've swithced off celluar data for icloud downloads problem solved