siri ios 7

It’s been discovered that Apple is using a new networking protocol called Multipath TCP in iOS 7. The technology allows devices like the iPhone and iPad to switch between both cellular and Wi-Fi for data transfer.

The find is credited to Olivier Bonaventure, a computer science professor at the IP Networking Lab in Belgium, who says this is the first large-scale commercial deployment of Multipath TCP and it has huge implications…

Christopher Mims of Quartz has a good explanation of the technology:

“It’s called multi-path TCP, and here’s why it matters and how it works: At present, if your phone or tablet is connected to Wi-Fi and a cellular network at the same time, it can only use one or the other connection to transmit data. But what if your Wi-Fi connection or your 3G connection drops? Whatever data was being transmitted—data for an app, a webpage, an iMessage—will fail to arrive, and you have to try again, usually after getting a frustrating error message or a blank page.”

With Multipath, a device like the iPhone would be able to intelligently switch between an active Wi-Fi and cellular connection to avoid disruption of data transfers. This would be based on connection speed, reliability, etc.

Olivier explains that he made the discovery while using an iPad running iOS 7. He was able to deduce that Multipath TCP was being used to connect to certain compatible Apple servers by actively monitoring its packet traces.

siriScreenshot showing the iPad using Multipath TCP

Right now, it appears that Apple is only using this protocol for Siri—which makes sense, given the services complexity. But the implications here are huge. Think iCloud, think iTunes media streaming, think app downloads.

  • Rickm_jr

    Outside of Siri? Think downloading a 5GB app on wifi, the ISP has issues thus connected to wifi and cellular so the app downloads by switching to and from cellular. Sucks if you’re on a capped plan.

    • Settings > Store > Cellular downloading > Off

      Btw, over cellular, the download limit it’s 100MB per app, so that won’t happen with 5GB files. But just in case, disable the cellular downloading in the Store.

      • Rickm_jr

        But if is only meant to switch between the two as the wifi restores connection then it might disregard the 100MB cap, or even connect to the wifi at the cap and switch again on failure. Assuming someone likes to use cellular for iTunes Radio and what not

      • Well, that’s a good question that I’ve made to myself too. Let’s see if someone can answer that.

        But i think the 100MB cap it’s only for apps, in the store.

      • Rowan09

        According to the article it’s only used right now for Siri.

      • Dinh Tran

        I tried to download infinity blade 3 with wifi and while downloading, I turned off wifi to get it with lte, it doesn’t work. It pops up the warning that it cannot download apps more than 100 mo.

    • you would be 100% correct if it were impossible to write logic statements in any programming language ever.

  • Itzhiss

    Nice bout time.

  • CC-Dog

    It’s clearly a GTK Wireshark under XQuartz.
    Why not use the QT version? It’s much better looking and responsive since it runs on Cocoa.

  • andrew boon

    Good article !


    Misleading title

  • abdullah575

    what is that ??

  • jocastro

    i thought they where doing that anyways, i was pretty sure they said it during the iPhone 5 unveiling

  • FOFF


  • Ben Anderson

    How on earth is this “huge”? It’s not like we spend most of our time jumping between wifi / cellular? I agree it’s a nice to have but it;’s certainly not a game changer.