After iOS7 launched, Multipath TCP allows for a connected device, such as an iPhone or iPad, to transmit data over multiple pathways simultaneously.Can any body explain how it can be implemented programitically or is it required to do anything programatically or does iOS take care everything u dont need to woorry about that?
iOS take care about everything. Classic TCP header is extended with MPTCP bits, which should be ignored by middleboxes between iOS and Siri servers. These bits tell both sides, all available IP address they can use and then MPTCP create connection between them.
MultiPath TCP is at this moment used only with Siri.
There exist Linux implementation of MPTCP you may be interested in.
Multipath TCP configuration is available for developers since iOS 11 .
Developers using high level communication classes such as NSURLSession , Can now choose between 3 different MPTCP modes , each suitable for different communication use case .
Just set the multipathServiceType property in NSURLSessionConfiguration to a mode other than none.
Read about it :
https://developer.apple.com/documentation/foundation/nsurlsessionconfiguration/improving_network_reliability_using_multipath_tcp
Related
I’m not talking about Reachability.
What I’m talking about is figuring out how to create a network connection from an iOS device across the cellular interface.
Why? Because I have conditions where the device connects to a WiFi access point so it chooses WiFi… but that access point is not internet connected and goes nowhere. I have data which I must make every effort to deliver and it some cases it’s getting lost in the WiFi gateway to purgatory. In both cases of using Reachability and relying on MPTCP, Apple has already given priority to WiFi in the stack.
I know NSURLSessionConfiguration can set allowsCellularAccess to allow cellular access — I’m looking to require cellular for the routing.
Even at the CFNetwork level I’m looking at kCFStreamPropertyConnectionIsCellular for status, kCFStreamPropertyNoCellular to disable cellular.
I can’t find anyway to give preference to the cellular radio. I realize Apple has gone to great lengths to prefer WiFi and I’m going against that — which is why I’m having such difficulty finding an answer to this.
I'd like to keep this up in the Cocoa level, but not opposed to going into Foundation or deeper levels. I would like to avoid trying to parse an interface table (if it's even accessible) to figure out which is the cellular interface.
Has anyone successfully created a network connection across the cellular link despite WiFi appearing to be present?
Is some configuration of Multipath TCP the answer here?
To bind to a particular interface, as far as I'm aware, you'd have to drop all the way down to the raw socket level, and there's no way to provide a custom socket for NSURLSession purposes, so you'd basically be rewriting it from scratch. You should file a bug asking for support for binding an NSURLSession to a source IP.
The behavior you're experiencing is a known problem with iOS and disconnected networks. iOS 9 and later do a better job, but even then, they can be highly problematic; the devices sometimes refuse to talk to the Wi-Fi network, and sometimes refuse to talk to the cellular network. Specifically, it seems to fail spectacularly if either signal is weak. Just this morning, I actually had to force my iPhone (iOS 10) to talk to a disconnected Wi-Fi network by putting it in Airplane mode and enabling only Wi-Fi.
I'm told that you can fix this by configuring the network's DHCP server to not provide a router advertisement; that said, every time I've tried that, the iOS device would just keep asking for an offer repeatedly. Maybe that bug got fixed at some point. If so, it might be worth a shot, but don't expect it to work in older versions of iOS.
Failing that, assuming you don't need to support web browsers in iOS 3 and earlier, you might try eliminating the DHCP server on that Wi-Fi network entirely, and just rely on DNS service discovery with zero-conf IPs. That way, the device won't see a router, and it won't try to send data out that interface except to those link-local IPs.
If that isn't possible for some reason, ordinarily I would suggest using a customized copy of libcurl, except that I doubt this will work in your case, because POSIX networking doesn't wake the cellular hardware.
In iOS 12 and later you can use the Network Framework. Sample code is here.
How can I implement Multipath TCP in iOS.
I hope as per the MultiPath Apple documentation we do not need to enable MPTCP in iPhone.
Is there any Multipath TCP samples for iOS
You should not need to enable MPTCP on the phone. MPTCP is already in use by iOS applications, e.g., Siri.
What the document you linked to is referring to is enabling MPTCP on your network. MPTCP uses TCP option 30. Many firewalls will not pass unknown TCP options. In order for your iOS app to use MPTCP, tcp option 30 needs to make it unmolested through the network to your server.
Further, your server must support MPTCP for the phone to negotiate an MPTCP connection.
This paper on a socket API for MPTCP has a code sample for using MPTCP on iOS and provides links to opensource code released by Apple that contain examples of using the API.
Multipath TCP is now open for any app in iOS11 beta. See http://www.tessares.net/highlights-from-advances-in-networking-part-1/ for a summary of the announcements at WWDC17. Apple does not expose the socket API mentioned in the previous post.
I have two entities which I would like to be able to start a communication:
Hardware Device Using Atmel ATSAMS70 and WINC1500 Wifi Module
HTML 5 App
The idea to have a HTML 5 app is to be able to communicate easily with most of the commercial devices like: Windows computers, Android Phones, Mac OSX computer and iOS devices. Apart from that, I would avoid working with native code at all.
Currently, they can talk with each other using WebSockets but somehow the IP address of the custom board has to be known from HTML 5 to initiate the communication.
In order to do this, I can think of 3 options:
Using WebRTC I can get the local IP address of the browser and then I could do a scan of the local devices considering a 255.255.255.0 network mask.
Have an external server that the hardware device can send its local address which will be later retrieved by HTML 5.
Using Bonjour or some sort of device discovery service between the board and HTML5.
I could not find a way to achieve #3 but #2 seems feasible to me. #1 is what I am doing now, but WebRTC is currently not supported on iOS.
So, is there any other better possibility to achieve this communication?
You don't mention how the WINC1500 unit is being connected to the network but presumably this is in STA mode (acting as a wifi station rather than becoming a software access point or part of an ad-hoc network) and is being provided with its IP details through an existing access point?
Ordinarily I'd suggest that once connected, the device ought to start indicating its availability on the network via a regular UDP broadcast on a specific port but my (admittedly limited) understanding of WebSockets it is that it creates TCP connections. The only implementation of Bonjour that I've seen uses UDP messaging too, that may be why you've had trouble with your third approach.
Your second approach seems more likely to work well. A server at a known (or discoverable) IP on the local network which allows the Atmel device to register itself (and its IP address) and also allows other applications (your HTML 5 WebSockets applications) to request that connection information to allow them to create the WebSocket TCP connections they need.
I suppose that doesn't really answer your question as to "Is there a better way?", other than to say "Not that I can think of, your second approach looks good to me...". Sorry! Sounds like a very interesting project, overall,
I have just delivered a prototype for a big client, everything was fine but I'm now curious to know if the solution/architecture I've chosen was the right one or there's place for improvement in case the project will keep on.
The task was to build two iOS apps: one running on 5 different iPhones, and another running on 2 iPads. Basically the iPhone applications had to communicate information to the iPads, and occasionally they also had to send information between each other (iPhone to iPhone). All the infos where small JSON objects/chunks whose size was small, really small.
The app was not intended to reach the app store, is a working prototype to test out some ideas in a user testing environment.
I discarded bluetooth because we are talking about a peer-to-peer communication, not a one-to-one.
What I did was to use web sockets thanks to SocketIO, through a small Node.js server that was running on my mac. The server was really simple, just receiving the messages from the clients and broadcasting information to the other ones.
What do you think? Is the solution I've chosen ok, or there are better ones?
For example, this morning I've just found out these thread here on SO, and I've discovered I could have used GameKit. What do you think?
Socket.IO is nice because it is fairly simple to implement but it has the downside of requiring a central server. If you wanted to avoid that, you could use the Multipeer Connectivity framework that was introduced in iOS 7.
It will let you create one-to-one communication channels between devices on either the same WiFi network or Bluetooth. Once the channel is created, you can send whole NSData objects (or create streams but it doesn't seem relevant to your use case).
A good read : http://nshipster.com/multipeer-connectivity/
The WiTap sample from Apple demonstrates peer-to-peer networking over Wi-Fi and Bluetooth. Using Bonjour, the application both advertises itself on the local network and displays a list of other instances on the network. Supports infrastructure networks, peer-to-peer Bluetooth, and peer-to-peer Wi-Fi (on compatible hardware).
I have personally tested it and it works fine and well documented.
I think socket.io is the best choice. It is built on top of engine.io (which in turn is built on the fastest websocket implementation: ws) It has oldest to newest fallbacks, so it starts with long polling and works its way up. This guarantees a quick initial connection instead of needing to poll the device for features. You can read more on this here. Best of all, it handles everything seamlessly. You write your code as if websockets are supported on connecting devices and if not it will use other methods behind the scenes.
This post details many of the websocket libraries you could use with your server. Which websocket library to use with Node.js?
I am convinced Bonjour is the best solution:
Apps can also leverage Bonjour to automatically detect other instances
of the app (or other services) on the network.
However I've never used it myself; perhaps someone who has can comment?
I'm trying to find out what AWDL is. On iOS, if you use Apple's peer-to-peer networking over BlueTooth, it seems Apple creates a new Network Interface "awdl0" to implement (I guess) IP-over-BT.
But I can't find any docs on this tech, or this interface, how it behaves, things we must / must not do with it, etc. Google comes up blank :(.
In particular, I believe it means "established a BT connection, and I'm running an IP bridge over the top, and you can use this to communicate peer-to-peer". Apple's own system libraries have bugs where this bridge isn't setup quickly enough, and if you send data too soon, it appears to get dropped by the OS. So ... if I can query this awdl0, I hope to check "are you ready yet?" and delay P2P messages until the OS is happy.
UPDATE
More info: I can get pairs of iOS devices to create awdl0 connections to each other - but they never get created to OS X machines, whether BT and Bonjour are on or not, whether the devices are paired or not.
Some background:
In iOS5, Apple permanently disabled the Bluetooth parts of Bonjour/Peer-to-peer networking, and published a technote instructing everyone to use DNS-SD if they wanted to keep using Bluetooth as a transport between iOS devices. This is fine, but it means you must use DNS-SD if you want high-performance BT, and you want it reliable.
(GameKit sometimes works fine, but we often see terrible performance in real-world scenarios, e.g. crowded public places - which goes away if you use DNS-SD)
DNS-SD protocol doesn't include info to tell you what the hardware is using. But it does tell you the Network Interfaces (which is how I know we're running on awdl0)
DNS-SD is awesome, and we have high-speed, low latency connections peer-to-peer between iOS devices - all the stuff that GameKit promises but often fails to deliver whenever there's more than a few wifi/BT devices in range.
AWDL recently caught a lot of attention when it caused Wi-Fi issues in iOS 8 and OS X Yosemite devices.
What is AWDL?
AWDL (Apple Wireless Direct Link) is a low latency/high speed WiFi peer-to peer-connection Apple uses for everywhere you’d expect: AirDrop, GameKit (which also uses Bluetooth), AirPlay, and perhaps elsewhere. It works using its own dedicated network interface, typically “awdl0".
While some services, like Instant HotSpot, Bluetooth Tethering (of course), and GameKit advertise their services over Bluetooth SDP, Apple decided to advertise AirDrop over WiFi and inadvertently destroyed WiFi performance for millions of Yosemite and iOS 8 users.
How does AWDL work?
Since the iPhone 4, the iOS kernels have had multiple WiFi interfaces to 1 WiFi Broadcom hardware chip.
en0 — primary WiFi interface
ap1 — access point interface used for WiFi tethering
awdl0 — Apple Wireless Direct Link interface (since iOS 7?)
By having multiple interfaces, Apple is able to have your standard WiFi connection on en0, while still broadcasting, browsing, and resolving peer to peer connections on awdl0 (just not well).
You can find more info here and here.
I'd like to provide a more precise answer as to how the protocol works internally. I quote part of the abstract of this paper.
In short, each AWDL node announces a sequence of Availability Windows
(AWs) indicating its readiness to communicate with other AWDL nodes.
An elected master node synchronizes these sequences. Outside the AWs,
nodes can tune their Wi-Fi radio to a different channel to communicate
with an access point, or could turn it off to save energy.
From a user perspective, AWDL allows a device remain connected to an infrastructure-based Wi-Fi network and communicate with AWDL peers "at the same time" by quickly hopping between the channels of the two networks (AWDL uses fixed social channels 6, 44, and 149). In contrast to the previous answer, we found that current versions of AWDL work fairly well and channel hopping only induces a small overhead.
Disclaimer: I'm co-author of this paper and we retrieved this information by means of reverse engineering. If you are interested in the details, please read the paper and have a look at the Wireshark dissector (published soon).