HT205296: About Wi-Fi Assist

Learn about About Wi-Fi Assist
Danny Lan

Q: iOS 9: Wi-Fi Assist

Hello all,

 

The new "Wi-Fi Assist" on iOS 9 (About Wi-Fi Assist - Apple Support) has been a hot topic lately so I decided to take a closer look at it.

 

On the above article Apple says that:

 

"With Wi-Fi Assist, you can stay connected to the Internet even if you have a poor Wi-Fi connection. For example, if you're using Safari with a poor Wi-Fi connection and a webpage doesn't load, Wi-Fi Assist will activate and automatically switch to cellular so that the webpage continues to load. You can use Wi-Fi Assist with most apps like Safari, Apple Music, Mail, Maps, and more."

 

By reading that you would conclude, by using regular logic, that if such function is "Off" then Data won't kick-in even if the Wi-Fi connection is poor/weak, however, it isn't the case, at least on my testing it wasn't:

 

- Running iOS 9.1 on an iPhone 5s.

- Currently Roaming internationally so "Data Roaming" is "On".

- Safari was used to load different pages.

- Since I own an MVNO (Mobile Virtual Network Operator) I could see on my system exactly when a Data session was being activated and actual Bytes were being transfered.

 

Result: Whether the "Wi-Fi Assist" is On or Off was totally irrelevant, it always switched to Data if the Wi-Fi signal was extremely low or was lost.

 

Also, on Apple's article they also state:

 

"Wi-Fi Assist will not automatically switch to cellular if you're data roaming."

 

This wasn't true on my testing as Data Roaming was "On" and it did automatically switch to Data when the Wi-Fi signal was extremely low or was lost.

 

The purpose of this post is to see if a Senior Apple developer in the iOS reads it and can comment on this.

 

Best,

iPhone 5s, iOS 9.1

Posted on Nov 3, 2015 7:16 PM

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Q: iOS 9: Wi-Fi Assist

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  • Helpful answers

  • by Lawrence Finch,Solvedanswer

    Lawrence Finch Lawrence Finch Nov 4, 2015 10:33 AM in response to Danny Lan
    Level 8 (38,076 points)
    Mac OS X
    Nov 4, 2015 10:33 AM in response to Danny Lan

    Senior Developers do not read Apple Support Communities. Actually, no one from Apple reads these forums; they are user-to-user support forums.

     

    When WiFi is extremely low the connection will be lost entirely or intermittently, and will iOS will switch to cellular, as it always has, regardless of the setting of WiFi Assist. WiFi Assist is different; if the WiFi connection is solid but the data rate is slower than cellular it will switch to cellular if WiFi Assist is on, and will not if it is off. These are two different situations. 

  • by Csound1,

    Csound1 Csound1 Nov 3, 2015 7:22 PM in response to Danny Lan
    Level 9 (50,801 points)
    Desktops
    Nov 3, 2015 7:22 PM in response to Danny Lan

    What is your question.

  • by Danny Lan,

    Danny Lan Danny Lan Nov 4, 2015 10:39 AM in response to Lawrence Finch
    Level 1 (80 points)
    Nov 4, 2015 10:39 AM in response to Lawrence Finch

    Hi Lawrence and thanks for taking the time for reading my post and replying to it.

     

    I understand what you said.

     

    Where did you obtain that information from? I couldn't find anything of that nature on Apple's site.

     

    Best,

  • by Lawrence Finch,

    Lawrence Finch Lawrence Finch Nov 4, 2015 10:59 AM in response to Danny Lan
    Level 8 (38,076 points)
    Mac OS X
    Nov 4, 2015 10:59 AM in response to Danny Lan

    Danny Lan wrote:

     

    Hi Lawrence and thanks for taking the time for reading my post and replying to it.

     

    I understand what you said.

     

    Where did you obtain that information from? I couldn't find anything of that nature on Apple's site.

     

    Best,

    8 year's experience using iOS devices and knowledge about WiFi technology. WiFi uses a spread-spectrum protocol that requires the sender and receiver be in constant communication, whether data are flowing or not (which is one reason iPhones disable WiFi when they go to sleep, to stop WiFi from draining the battery). The protocol can compensate for occasional random dropouts by changing frequencies and resyncing, but if a connection cannot be reëstablished within a couple of seconds the WiFi chip will report loss of connection and the phone will disconnect. If cellular data is enabled it will switch to it, just like it will use cellular if there is no WiFi available or if you move out of range of the cellular signal.

  • by Danny Lan,

    Danny Lan Danny Lan Nov 4, 2015 12:28 PM in response to Lawrence Finch
    Level 1 (80 points)
    Nov 4, 2015 12:28 PM in response to Lawrence Finch

    Hi Lawrence, thamks for the additional information/explanation.

     

    So how exactly did you arrive at the final conclution of:

     

    "if the WiFi connection is solid but the data rate is slower than cellular it will switch to cellular if WiFi Assist is on, and will not if it is off."

     

    Did you performed testing yourself or did you read it somewhere (where)?

     

    Best,

  • by KiltedTim,Helpful

    KiltedTim KiltedTim Nov 5, 2015 10:44 AM in response to Danny Lan
    Level 9 (55,886 points)
    Mac OS X
    Nov 5, 2015 10:44 AM in response to Danny Lan

    It's not necessary 'slower than cellular', it's more a matter of it just being extremely slow... timeouts and errors, etc. It's not uncommon at all for many home "broadband" connections to be slower than LTE cellular data speeds.

     

    I can tell you that if WiFi assist is off and there is a solid WiFi connection with no Internet access, the phone makes no attempt to switch to cellular data. With WiFi assist on, it does switch to cellular data. I've tested this with a WiFi access point that does not have an Internet connection.

  • by Lawrence Finch,

    Lawrence Finch Lawrence Finch Nov 4, 2015 12:51 PM in response to Danny Lan
    Level 8 (38,076 points)
    Mac OS X
    Nov 4, 2015 12:51 PM in response to Danny Lan

    What Tim said. I've done similar tests. My complaint is that with WiFi assist off it doesn't revert to cellular when the WiFi connection is too weak to be usable; I have to turn off WiFi when leaving my garage to use Waze, for example. But that's not new.

  • by Danny Lan,

    Danny Lan Danny Lan Nov 5, 2015 11:03 AM in response to KiltedTim
    Level 1 (80 points)
    Nov 5, 2015 11:03 AM in response to KiltedTim

    Hi Tim,

     

    Thanks much for that additional info., now everything makes sense.

     

    Apple should edit article HT205296 in order to:

     

    a) Clarify that the usual switching from Wi-Fi to Data when Wi-Fi connection is lost remains the same as in previous iOS versions and that such behaviour doesn't change with the introduction of "Wi-Fi Assist".

     

    b) Explain better what "Wi-Fi Assist" actually does and include a couple of practical, real-life examples of how it works in layman terms.

     

    That would must likely help in handling must of the heat they been getting because of the misinformation circling around.

     

    Best,

  • by Danny Lan,

    Danny Lan Danny Lan Nov 5, 2015 11:05 AM in response to Lawrence Finch
    Level 1 (80 points)
    Nov 5, 2015 11:05 AM in response to Lawrence Finch

    Hi Lawrence,

     

    Got it on what you're saying.

     

    Best,