Previous 1 2 3 4 5 Next 74 Replies Latest reply: Oct 6, 2013 8:39 PM by Dino Penguino Go to original post Branched to a new discussion.
  • Exitcomestothis Level 1 Level 1 (5 points)

    To get into field test mode, open the phone app, then enter *3001#12345#*, and press call. This will open a new window.  Under PDP Context Info, there will be 4 separate entries (0-3).  Context 0 is where the APN settings for cellular data are listed.  Context 2 is where the elusive MMS functionality is listed.


    Are you using wap.cingular?


    I think at this point, the culprit definitely is the APN's inability to allow concurrent PDP Context's, becuase when using the standard "phone" APN that the iPhone is configured to use by default, FTM does show PDP 0 and 2 having an IP.


    However, Apple should know better than to assume that all APN's will support concurrent PDP Context's, and should allow some sort of setting to be applied through the iPhone config utility to address this issue.


    As per the head "genius" at the genius bar, "This isn't an apple issue...".


    I wonder if forcing the phone to use an APN that supports concurrent context's is part of the GSM Standard?

  • Tragopogon Level 1 Level 1 (5 points)

    Strangely enough, my phone has been quiet on PDP 2 for the last two days which is a record as far back as I remember having it.  The console log shows heartbeat requests every half hour or so to PDP 0 to keep the connection alive for push services, but that's been it.  Battery life/etc has been fine.  Not that this means this lucky streak won't end.  I'm going to try to use MMS and iMessage in this state and see if that has an effect to make sure it isn't because people haven't been messaging me .


    It seems from reading around online that other phone models may make use of multiple PDP contexts on GSM and that this function isn't particularly new.  For example, running in tethered mode may use separate contexts for phone OS services and tethered data.  It sounds like GSM Blackberries may use multiple contexts with different quality-of-service standards, e.g. a more reliable connection for push notifications than say general web browsing.

  • onecount Level 1 Level 1 (0 points)

    There is no doubt that multiple concurrent PDP sessions and multiple IP addresses per client are totally allowed by the standards. I think in GSM, a mobile client can have at least 6 IP addresses (may not all be used but the standards allow it).


    But I am still not clear on how this is AT&T's APN problem. Here are my doubts/questions:


    How come the commercial iPhone4S you buy with contract from AT&T does not have the issue? What APN does that use for cellular data and what for MMS?


    I also read about the default APN called "iphone". Is this an AT&T APN? Is this different from wap.cingular? (and yes, I am tryng to use wap.cingular). Does the "iphone" APN allow multiple concurent PDP sessions? If I create a config profile and put "iphone" as the APN, will the problem go away?


    And finally, let's say this is a limitation of the AT&T APN. When you install a profile with a private APN, you dont have any conflict with AT&T's APN any more. Because your cellular data is configured to go over your private APN and MMS is configured (based on what I read in this discussion) to go over wap.cingular. These are two differrent APNs and neither of the two is asked to hold concurrent PDP sessions. But we still have the problem even in this case.


    In any case, I still think there is something for Apple to address here. And thanks for the field test instructions. I will attempt them when I get off work and report back.

  • Tragopogon Level 1 Level 1 (5 points)

    How come the commercial iPhone4S you buy with contract from AT&T does not have the issue? What APN does that use for cellular data and what for MMS?


    The default APN for postpaid AT&T for the 4S appears to be "phone" (versus e.g. wap.cingular for prepaid).  I don't believe separate APNs are being used for data/MMS; in the case of the 4S it appears multiple PDP contexts within an APN are attempting to be used.


    Anandtech's 4S review ( mentions:


    For a while, I was concerned that AT&T would continue using the wap.cingular APN on the 4S which seems shaped to around 7.2 Mbps HSDPA. I’m glad to report that AT&T hasn’t continued using wap.cingular on its 4S data plans, instead using “phone” which is a newer APN that allows for HSPA+ (above 7.2 Mbps) rates. You can check this yourself under PDP Context Info on the 4S in field test.


    If wap.cingular is being used as the default or even as a user-specified APN for previous iPhone models (which only support HSPA, and apparently don't make use of multiple PDP contexts), that would explain why other iPhones aren't having this issue.  The new HSPA+ APN the 4S uses apparently does support and use multiple PDP contexts, as noted in this thread.



    • wap.cingular (pre-iPhone 4S, GoPhone) = HSPA speed, supposedly no multiple PDP contexts
    • phone (iPhone 4S) = HSPA+ speed, allows multiple PDP contexts 


    Of course, if you're not on a postpaid 4S plan, attempting to use "phone" as the APN (or by default) on your 4S will cause messages to pop up saying you're not subscribed to data.

  • onecount Level 1 Level 1 (0 points)

    Thanks for all the above information. I did try the test on my postpaid 4S and, as expected, I saw "phone" and "wap.cingular" for APNs (context 0 and 2 respectively). Both contexts had valid IP addresses.


    If I make a config profile with "phone" as the APN and push to this 4S device, MMS works fine. PDP contexts 0 and 2 have the exact above values after installing the config profile.


    The part I need to understand is the behavior when a private APN is pushed through a config profile. I dont have one to try. I saw in previous posts from Exitcomestothis that in this scenario MMS fails as well. Is this a postpaid or an unlocked device? If we have a failure in this case even though two different APNs are used (the private for cellular data and wap.cellular for MMS), then we do have an issue that needs fixing.


    What Apple could do:

    1. Have some kind of fallback if the APN does not support concurrent sessions.

    2. Provide the ability to set MMS APN through IPCU.

  • Jeremy Morse Level 1 Level 1 (20 points)

    onecount wrote:


    2. Provide the ability to set MMS APN through IPCU.

    Exactly! I can understand everything but this -- with IPCU, one can set literally everything else, but why not values for MMS? I'm facing a related but different problem (using IPCU to upload an alternate profile), but I need to be able to input a value for MMS. If I were using a standard configuration, it would be so simple -- Cellular Data Network settings pane allows you to input these values. But as far as I can see, the Enterprise-grade utility IPCU utility, cannot. Strange.

  • Jovian Remix Level 1 Level 1 (0 points)

    I'm having the same problems. I need a fix without changing my data plan with ATT. Everything works with iMessage (SMS/MMS) but when not using iMessage...I can receive MMS but I cannot send MMS.

  • onecount Level 1 Level 1 (0 points)


    I did the field mode test today with an iPhone4 on iOS 4. This a commercial AT&T device (with contract) that we intentionally keep at this iOS level exactly to check issues like this. The device is not jailbroken. I installed a config profile with the "wap.cingular" APN. Then I sent an MMS message (successfully). Immediately after the message was sent, I launched the field test mode to check PDP contexts. There were two. PDP 0 and PDP 1. They both had different IP addresses and they both showed "wap.cingular" as the APN. PDP 1 was short-lived. It stayed on for only a little bit following the successful sending of the MMS, and then it was closed.


    This tells me that there is nothing wrong with APN wap.cingular. This APN, apparently, does have the ability to support multiple PDP contexts from the same client just fine. The iPhone4S does behave different by maintaining (or trying to maintain) two permanent PDP contexts whereas the iPhone4 opens the second one only as needed. Any thoughts?

  • macCrucial Level 1 Level 1 (0 points)

    So how do we actually make this work?


    I am using a stock AT&T iphone 4S on AT&T.


    I know what the problem is, just don't know how to fix it.


    My service does NOT have the iphone Data Package on it. I am using a generic data plan (I'm on an old old employee plan) and thus my data/phone will not activate as it usually would when the phone is powered on the first time.  To get around this, I use an APN changer site on WiFi to install the AT&T APN settings and then whola, my iphone is activated and data starts working.


    With my iphone 4 I had no problems with MMS working, but there is something different going on (I assume bc of iMessage) and I now can not get MMS to work unless using iMessage. Also, when sending/receiving texts to other networks, sometiems there is a huge delay from when I send and they receive.

  • onecount Level 1 Level 1 (0 points)

    The APN changer you are using most probably installs a config profile with wap.cingular as the APN to your device. As we have decided in this discussion thread, if this is your APN, MMS will NOT work on iPhone4S, as it stands right now, no matter what you do. Apple may fix in a future release, we will see.


    iMessage has nothing to do with it. iPhone4 can support iMessage (as long as it has iOS 5 on it) and MMS works fine there.


    As to what to do, please see my post on Jan 11 to see if that helps you.

  • macCrucial Level 1 Level 1 (0 points)

    So you're telling me there's not a different apn that would work, or a .plist file I could edit to correct this problem? I know there is a similar problem people are having and they have gotten it working by replacing one of the config files.  If the iPhone 4 doesn't have the problem, maybe swapping a file from that phone would patch it?


    I'm seriously going nutz, I use mms for work, I've had to rely on e-mail but that just creates other problems.

  • valongoria Level 1 Level 1 (0 points)

    I was messing with the different apn profiles from unlockit...i found isp.cingular profile working and able to send mms. Im just not sure if it would change my data plan since that plan is usually not for unlimited data plans.. if it does not effect my monthly charge, someone please let me know. Everything works using isp.cingular apn profile from unlockit..should i keep it or change it back to wap.cingular...

  • macCrucial Level 1 Level 1 (0 points)

    I just tries that profile and it won't activate cellular data, so my Internet wouldn't work for all my apps (safari). Is yours?

  • valongoria Level 1 Level 1 (0 points)

    Hmm thats weird everything works perfect on mine...(iphone 4s) just dont know if it would charge me any different..

  • macCrucial Level 1 Level 1 (0 points)

    AT&T used to have different apn's for different devices (smartphone, mobile wap phones, broadband cards) and by using a different apn you'd get different levels of access and bandwidth. Now says, if it works then you can use it and you'll be billed based on your data package.  In other words, of it works the you're fine. Just be careful when roaming outside USA.


    I'm still confused at why it's working for you, I've tried twice now and unless I'm on wifi I have no data with that profile installed.