UPDATED: Are AT&T's iPhone Problems Due to Network Configuration Errors?


UPDATE: TiPb asked for AT&T's side of this story, and here it is:

"The AT&T wireless network is designed and engineered to deliver the highest possible levels of capacity and performance. Our standing as the nation's fastest 3G network is validated by multiple third-party testing organizations on the basis of millions of drive tests annually.  

"We believe that recent online speculation regarding AT&T wireless network configuration settings is without foundation. Allegations in these posts regarding packet loss network settings are incorrect."

ORIGINAL: In a post entitled Has AT&T Wireless data congestion been self-inflicted? the blog Communications explores whether the iPhone-on-AT&T problems we keep hearing about are the result of misconfigured buffers in AT&T's mobile core network leading to congestion collapse.

It appears AT&T Wireless has configured their RNC buffers so there is no packet loss, i.e. with buffers capable of holding more than ten seconds of data. Zero packet loss may sound impressive to a telephone guy, but it causes TCP congestion collapse and thus doesn't work for the mobile Internet!

The article is way over our heads, but give it a read and let us know your take-away. There's obviously something going on that results in iPhone users on AT&T, especially in New York and San Francisco having connection issues, dropped calls, etc. Could this, at least in part, explain it?

Rene Ritchie

Editor-in-Chief of iMore, co-host of Iterate, Debug, Review, The TV Show, Vector, ZEN & TECH, and MacBreak Weekly podcasts. Cook, grappler, photon wrangler. Follow him on Twitter and Google+.

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There are 36 comments. Add yours.

matthew23 says:

That's actually what I was thinking.

VDR says:

That explains why my GPS isn't working properly on my 3GS.

flyingember says:

VDR- gps has nothing to do with AT&T's network. that comes from satellites.

Dan says:

@Kevin: it does. It's aGPS so it initially relies on the networks cell tower possition to triangulatr the device's position.

Therealtruth says:

@dan all assisted gps means is that cell towers are used in conjunction with sattelites. The iPhone has a gps chip in it. That's all that is needed to get a signal. Triangulation from cell towers is simply used to assist in the accuracy

ThisBrian says:

Dan@ that is what I understand too, no cell service is needed for GPS. Cell towers are just a bonus.

Caballera says:

I would take it all with a grain of salt. I see people like this all the time (not with AT&T but where I work) who claim to know what the issue is, however they very rarely have all the information and usually missing critical information. I would be more interested in a response from AT&T if they gave one to this guys theory.

jeversion1 says:

OK so here is a weird problem that i noticed. A close friend of mine who is also on AT&T and owns the new...dont hate me for this....lovely 9700 bold blackberry, were out in a outer suburb here in Cleveland, OH. I watched as my iphone searched for a signal, found 3g, went to edge, searched again for about 15 mins only to give me 2 bars of edge again while the 9700 never loss a 3g signal. Granted it could have been lying but I doubt it. But I know this issue isnt really seen with iPhones overseas and such. So what problem is that then? I still think its something with the way ATT has the iphone set up as opposed to it being an iPhone problem.

Republicans are a dying breed. says:

So you think that our iphones are communicating with satellites? And somehow our batteries dont die instantly? The GPS is most likely transmitted through our carriers towers, from a satellite. Everything goes through the internet these days guys.

TinyDawg37 says:

I dunno but I am probably one of the few who hasn't had any problems with my iPhone. But then again I don't live in a big city but I still get GREAT reception and GOOD Internet speeds on my phone. I Am very happy with it. And AT&T rates are cheaper than verizon for the exact same plan I have with AT&T. Go figure.

bubbatex says:

Out of all I read, I believe two things - ATT's network is over-taxed in many areas and the iPhone itself is not a very good cell phone from a radio standpoint.

ndrasheta says:

The GPS signal still works even when you are oit of cell coverage.

CharFeld says:

Maybe it's corporate sabotage! The cell phone competition has taken a turn to the nasty lately

flyingember says:

yes, the phone accesses a satellite. otherwise you would just have the circle the 2G has.

htc news says:

My service has been much worse in the last month. I was starting to think that Verizon has installed jammers to give the impression the ATT network has a glass jaw. Before that time i would drop one call every two months. Now I drop about 3 calls a day!!!! This is happening in the same places that I used to have good service.

icebike says:

I'm with Caballera.
The fact that packet starvation might occure due to congestion would not lead to call drop, simply short dead air gaps in the conversation.
I read about this some months ago and it didn't sound right then and hasn't become more believable since.
Congestion does not close or destroy tcp/ip connections. It just slows them down. Further this is a tcp problem. However voice goes over a packet switched network (usually frame relay) that is not the same as tcp/ip.
Since Att has the best data rate according to stories recently published here in TiPb, it hardly seems that congestion is an issue.

ThisBrian says:

Yea, It must be the little Martians that make my gps work in the middle of the desert with no cell coverage.

Georgie de curioso says:

I hope all republicans go extinct.

Earless puppy says:

If they are all as smart as him, come on ice age!!!!!!

fassy says:

If tipb can ask, I would be curious to hear AT&T or Apple's take on Ars speculation that iPhone power management shares some culpability here:
The relevant quote from the article:
A source—who requested we not reveal his identity—told Ars that the problem isn't the cell radio hardware, nor the network infrustructure, but an issue with the way that the iPhone OS conserves power. All iPhone apps, including Phone.app, cause the radio to switch from "active" to "idle" mode when accessing the network far more often than traditional phones do. This causes the signaling channel, responsible for such functions as SMS messaging, initiating, maintaining, or ending a phone call, voicemail notifications, and DHCP requests, to become overloaded.
"This can lead to odd effects," the source told Ars. "For example, you could be in an area with perfect 5-bar reception, but because the signalling channel is overloaded your phone won't ring and calls go into voicemail."

flyingember says:

fassy- I read that at Ars and wondered about that. this would help explain why Apple only allows a single notifications connection and not lt a bunch be open at the same time

just_me#IM says:

All I know is that in Sacramento CA on my 3gs and my other friends who have them in the area, our phones are dropping calls like crazy recently in our houses. Calls aren't even coming through and when they do they're dropped. We're not even getting alerts of a missed call either!! It was never great but now it's just ridiculous how bad it is.

steve weinberg says:

Smart phone? !!!! My sentiments and my experience exactly. Actual loss of service compared to previous months. How could that be? Anybody else?

Rene Ritchie says:

@Fassy -- AT&T typically suggests we direct those types of questions to Apple.

fassy says:

Please do then :)
Actually, a way to pose it to AT&T would be simply to ask if the network problems (especially in NYC and SF) are a result not of inadequate network coverage, but an overloaded signaling channel.

Aldiggi says:

I believe it really has to do with the radio chip inside of the iPhones. My wifes Sony Ericsson c905a holds a signal so very well and the sound and call quality is superb!! When we are together in the car and are driving and so happen to be one the phone at the same time my phone drops and she is chatting away the whole ride through!!

Limegrntaln says:

Someone needs to test the phone for this kind of thing on the network. And stop testing the network. The network has proved time and time again its fairly solid.
http://www.phoneplusmag.com/hotnews/3g-tests-show-att-faster-than-verizo...... See More... See More

VDR says:

@Kevin, yes it does, see below.
@Dan, thank you.
@Kevin, you're mistaken, and 2G shows as E which stands for Edge, and the circle represents GPRS (1G if you will), and see below.
@Brian, @Caballera, see below.
@jeversion1, my wife has the Blackberry 9700 Bold that was given to her by her company, and we commute together, so I always check and compare our receptions as we both are with AT&T.
@Republicans..., thank you.
@GPS Guy, you're mistaken, see below.
As for everyone who was asked to “see below”, here's my response to you all:
I had my very first GSM phone (on the 900 MHz frequency band, and no it wasn't in USA) back in 1988, so I've known and been using GSM before most of you even know what that was. And when I say something about GSM related topics, I talk about it based on my 20+ years of experience and facts. I don't wish to make this an attack post, but here are my facts. I have 2 iPhones, one is 3G and the other is 3GS. Both are Jailbroken and unlocked. I also have two SIM cards, one with T-mobile and the other AT&T. With T-mobile, my Google map app on both of my iPhones pin-point my location precisely with the blue dot, and when driving or walking the blue dot moves and updates my location as I move. Now, when with the AT&T SIM being used, none of my iPhones show my precise location, they're always 1 or 2 miles off; moreover, the blue dot will never move and update my location when I'm mobile. Also, when I have no signal (neither 3G, Edge nor GPRS), the blue dot will never show my location, and similarly, “Find My iPhone” feature never works when I have no reception. In addition, I get much better precise location on the map with WiFi than I get with full bars of AT&T reception. So whether or not any type of GPS module is found in our iPhones, it won't work without the GSM provider's signal/reception. Merry Christmas to you all!

Jack Kwack says:

At least people are starting to realize there is a problem beyond people just making a big deal about the occasional dropped call.
Seriously, here in San Diego it is nearly impossible to hold on to a 3G call. Regardless of full signal, in the car, at home, sitting on the beach, middle of the day or middle of the night, if you actually use your phone for a call of more than a few minutes, that call is very likely to drop.
AT&T attempted to blame it on everything, including, if you can believe it, the weather (come on, it was late summer in San Diego -- there hadn't been anything resembling weather here in 200 days) they finally just told me to turn off 3G and to call in each month for a credit. They don't even bother to hassle me as to why when I call in.
Sure, data speeds on 3G might be fine most of the time, but not mine, not my wife's, not any of my friends AT&T phones can hold a 3G call either... Something's going on that goes beyond simple overloading. I see these same kinds of things in New York and San Francisco (but not in various boonievilles I've visited).
The article may not present the exact answer, but given the consistency of the issue, and the fact that it is almost strictly limited to 3G, I'm glad somebody is giving it a deeper look, because AT&T sure can't seem to figure it out.
It is no wonder AT&T is having image problems.

cMc says:

For starters I live in Atlanta , but I'm visiting West Palm for Christmas. My 3g service generally is pretty good except when deep inside of buildings. Speeds can vary usually 1800-2200 kbs/sec. While on vacation, I'm finding that the 3g connection is very spotty from inside the house. At one point it registars 1-2 bars of edge and 1 min later 4 bars of 3g. Despite the reading conection speeds generally are poor, and tonight even with 3 bars if 3g, no connection to Internet at all. I ultimately went into settings and disconnected from 3g and reconnected. This would convert from edge to 3g and helped with connection issues but only briefly. I've never had connection issues like this while in Atlanta. Thought I would pass it along.
...FYI, many more dropped calls/call failed and battery life has been horrible (assuming this is related to phone trying to connect/searching for service)

vanityeverlastingbonet says:

Not trying to be a b-word but from that pic of the guys on the pole.That's what you get for trying to be cheap and hire illegals

Dww says:

@Republicans - GPS doesn't involve communication. It involves the phone listening for signals from a network of satellites. It finds at least 3 incoming signals and, based on the timing information encoded in the signal and signal strength, the chip in the phone calculates geographic position. It's strictly a one way, passive path from satellite to phone.

Charles says:

I drop calls on 3G about 80% of the time when I'm at home so now I just always leave my iPhone on edge. It sucks but the slower connection is worth not dropping calls all the time.

Hipolito M. Wiseman says:

Thanks for the information, appreciate it. I'm certainly looking forward to other blog posts. :)

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