Can anyone explain how bonjour works over bluetooth from iphone OS 3.0 onwards?
The documentation says the Bonjour API's used in the application just works even if Wi-fi is off and Bluetooth is on. It also says , a Bluetooth PAN is established and hence IP address comes into picture.
But Bonjour (based on mdns) requires multicast to work. But , Bluetooth PAN (piconet) works on a master-Slave concept. Any data to be exchanged between peers has to go to the master first and then the master forwards to the all clients. Moreover there is a restriction on the number of slaves in piconet i.e., 8. that means bonjour over bluetooth has a limitation that it would work for a max of 8 devices?
Apparently, it's PANU to PANU communication. So the limitation is actually - one-on-one communication. If you use Bluetooth Explorer, included with Xcode, you'll see the iOS device presents a service with ID 0x1115. Since there is no GN nor NAP nodes in the connection, only two devices can participate in the connection.
Bluetooth Explorer also shows various custom fields that serve to exchange metadata about the connection. See my somewhat related question for an example of the service announcement.
I have only been able to get this service to appear when using GameKit, on both iPhone 3G with 4.2.1 and iPad with 5.0.1.
I know nothing about Boujour and iPhone... Perhaps Bonjour just sees the TCP/IP network and multicasts on to it -- regardless of whether the IP network is over bluetooth or WiFi or FooBar...
IIRC PAN just forms a point-to-point link to the PAN peer and, thus if the peer is an access-point (rather than just another end-node) it it it that will handle multicasting the packets.
Related
I need to communicate my app with 2 devices. A restriction is that I can't use a server but all iOS devices will be in one Wi-Fi network. What options do I have? How I can send a message to another copy of my app running on another device?
I dont know whether its a correct approach or not but as you cannot use server,so the approach i can think of is we can create a socket connection using TCP/IP or UDP(based on reliability) for data exchange.
I dont think you can communicate between 2 devices running the same application without having some kind of server application in-between.
Even if you could find the other device over the WIFI I dont think you can tell if the other device is running the app or not.
I think you may be referring to MultipeerConnectivity
The Multipeer Connectivity framework provides support for discovering
services provided by nearby iOS devices using infrastructure Wi-Fi
networks, peer-to-peer Wi-Fi, and Bluetooth personal area networks and
subsequently communicating with those services by sending
message-based data, streaming data, and resources (such as files).
Source: https://developer.apple.com/library/ios/documentation/MultipeerConnectivity/Reference/MultipeerConnectivityFramework/
Apple Sample:
https://developer.apple.com/library/ios/samplecode/MultipeerGroupChat/Introduction/Intro.html
Am I missing something glaringly obvious or is there no way to debug an iOS app which uses an external accessory that's connected via the 30-pin dock without using a bucket load of logs etc. I want to be able to use things such as breakpoints and Instruments.
Is there a way to remote debug perhaps, over Wi-Fi, Bluetooth?
Note: Yes, I asked this very recently and I deleted it because I thought I found the answer.. but the answer was only Instruments has support over Wi-Fi.. not Xcode debugging. So the question still remains...
And so...: Given that I've had no real luck finding the answer, and no one has given me an answer as yet - I take it that it is a big fat NO. :(
Makes me wonder are we just expected to magically guess where bugs occur, or log the crap out of everything while wearing out our dock connectors by continuously moving it back and forth between the device and accessory?
Time to file a bug report I guess.
At CES today, I talked to a developer from Wahoo Fitness that makes an ANT+ accessory for iPhone. They had this same problem, but found a solution.
They found a pass-through dock extender that has a mini-USB port. They used the mini-USB port for debugging while the accessory was connected.
The product they were using is http://www.cablejive.com/products/dockStubz.html
This blog talks about remote debugging iOS with a dock accessory attached
You could connect the external accessory to another iOS device (not the one tethered to the Mac running the Xcode debugger). Then tunnel all your EA framework messages from the accessory connected device to the device running the app being debugged over a pair of wifi sockets. Look at the code for tunneling accelerometer messages from a device to the iOS Simulator (a common trick for debugging game code on the Simulator) for one example of how this could be done.
After further researching, and having seen that people had to do sending strings over Wi-Fi to get around this, I'm concluding the answer is no.
I have filed a bug request for this.
In the mean time, it seems like the Wi-Fi logging, and on-device text logging will be the way to go for now.
Here's my understanding for why just the USB protocol works for some external accessories and doesn't for other external accessories. Looks like a fundamental problem, without an arbitrator, two masters can't talk to a single slave over USB, a serial Master/Slave protocol. So XCode is one master, the iPhone is the slave device. If the external accessory is a master too, one won't be able to connect the iPhone (Xcode slave) to the second master (the external accessory).
Probably the Wahoo Key for iPhone" is a slave device and that's why the dockStubz solution works for such an external accessory.
I have tested the dockStubz. It doesn't work for my external accessory. As suspected, the USB protocol can't be used to have two Master devices controlling a single slave device. Trying to hook up a Mac (Master) (via the mini USB ) & an external accessory (Master) (via the 30 pin connector) to the iPhone 4 (Slave) causes the iPhone to go in loop of connect & re-connect.
Following looks promising too, though expensive: digi.com/support/kbase/kbaseresultdetl.jsp?id=485.
Has any one tried to use USB to Ethernet connectors and use a router to route requests from two masters (XCode & External Accessory) to the slave (iPhone)? I am off to Best Buy to purchase USB to Ethernet cables and hook all three on to my IP router. Will report if it works.
This is what will be needed :
http://www.bestbuy.com/site/IOGEAR+-+USB+Ethernet+Extender/9614781.p?id=1218131339965&skuId=9614781&st=USB%20to%20Ethernet&cp=1&lp=1
http://www.frys.com/product/6103339
So connect XCode mac using the male end into the USB slot of your computer. . Use a ethernet cable to connect this to a router.
Connect the iPhone to the female part of the IO gear connector. Connect it to the router via ethernet cable.
Connect the external accessory with the male connector (Sabrent USB to Fast Ethernet Network Adapter.) Connect it to router.
I am still researching if this will work. Just ordered the parts. Will get it by Friday & will report back then.
Update:
The IOGear male end draws too much current when connected to router. Also, the female end can't charge iPhone when connected to the router even when 5V USB current supplied.
So tried to directly connect the iPhone to the USB slot of the router (used for printers). It does charge the iPhone. Also used USB to Fast Ethernet Network Adapter (BestBuy had one to connect Wii via USB) to connect the Mac to the router. It did connect to internet but couldn't find the iPhone. In the router client list I don't see any login entires for the iPhone. So this experiment was a failure unless someone have other pointers.
I'd love to be able to mod the iPhone tcp/ip stack to route packets over the accessory port either serial or better yet USB or Firewire...
The applications I'm researching wouldn't be able to use WiFi, 3G or bluetooth...
Custom apps could be written to use the serial port available via the accessory port, but it would be nice to support generic apps that need network access.
I haven't tracked down much info relating to this, anyone have thoughts??
About the only way this could work would be to Jailbreak the device, and do some quite low level hacking. OS X supports NKEs (Network Kernel Extensions) that would allow you to introduce a new network interface. I don't know if the iPhone OS has these (as there's obviously not much information on it - it's supposed to be a black box). Even if it did, you'd have to make your KE lie and claim to be e.g. the Wifi device, as many applications will probe for network availability by searching for the Wifi interface.
Basically, I think this is an untenable idea. You can use the External Accessory APIs to allow your custom apps to use your dongle as a network service provider, but you can't use it to provide a new network interface. If you want this kind of open, extensible platform, then the iPhone is not really the right platform.
We bought a Grace wifi radio. Grace has a cool iPhone app that connects to the radio and lets you control it.
My question is.. how the heck does this work? How can the iPhone connect to the radio and then control it??
I can't find detailed technical information on Grace's side, but, if I were asked to design something like this, I'd have the radio advertise a service on its wifi LAN via zeroconf (also known by Apple's trademarked name, bonjour -- an app on the iphone (or any other node on that wifi LAN) can then easily find the radios on the same LAN and chat with them through whatever protocol Grace has defined for the purpose.
Edit: from the scarce crumbs of docs on Grace's site it seem they may have chosen UPnP instead of Zeroconf -- ah well, see here for a (possibly biased, but solid) analysis of why they should have chosen Zeroconf instead!-)
Are you asking coding specifics or just an overall concept of what's going on? The actual networking stack behind these operations can be quite complex.
Your Grace wifi radio will have created a server which the iPhone has connected to on your wifi network, from this point onwards it's a simple client-server relationship, with the iPhone sending data to the radio each time it sends a command. Because of this, if your iPhone is not on the same wifi network it will not be able to control/find the radio.
Most likely, the WiFi radio listens over a fixed UDP port. The iPhone in turn sets up a UDP connection by broadcasting the network (on IP 255.255.255.255) on that port. The radio will respond and a connection will be established.
This is complete speculation; I have no idea how it actually works. No doubt there is plenty of documentation on this.
I am using the reachability code from apple to find if my iphone is connected to the wifi. Next i would like to list all the devices that are in my wifi range. How should i do this. The other devices do not publish any service. I want to detect all devices in my wifi range and send that device a request for tcp connection.
If a device does not advertise its presence and is not otherwise active, TCP/IP does not give you a way to "detect" it. If you can identify your subnet (which has nothing to do with a "wifi range", whatever that may be), you can try connecting to each possible host in it on all possible ports -- this is generally considered an attack (what legitimate reason could you have for such a port scan?), so, if you're detected trying this attack, be prepared for the consequences.
As #Alex says, even if you could find devices that weren't advertising, what's the point? You can't most likely do any adhoc communications with them. Instead you'd need to find copies of your application running on connected devices, and your app needs to advertise.
Take a look at Gamekit sample projects which will give you bluetooth connectivity, and you could dig into something like Jens Alfke's MyNetwork and Blip libraries for tcp/wifi. http://jens.mooseyard.com/2008/05/blip-come-n-get-it/