Does Reach-ability class keep sending / receiving data in iOS dev?

Question

I have been working on Reachability class for a while and have tried both the one from Apple sample and the one from ddg. I wonder whether the Reachability class keep sending / receiving data after starting the notifier.

As I'm developing an app which connect to different hosts quite often, I decided to write a singleton and attach the reachability classes I need on it. The reacability classes would be initiated and start their notifiers once the app start. I use the singleton approach as I want this singleton class to be portable and can be applied to other apps without much rewriting. I am not sure if it is good idea to implement like this but it worked quite well.

However, someone reported that the battery of his device drain significantly faster after using the app and someone reported more data usage. My app does not send / receive data on background so I start wondering if it is related to the reachability.

I tried profiling the energy usage with Instrument and I notice that there are continuous small data (few hundred bytes in average) coming in via the network interfaces even I put my app in idle. However, there are almost no data sending out.

I know that Reachability requires data usage when initiate (resolving DNS etc) but I am not sure that whether it still keep using data after starting notifier. Does anyone can tell?

I am not familiar with the low-level programming, it would be nice if someone could explain how does the Reachability work.

Answer 1

I use Reachability, and while I haven't monitored the connections, I have browsed the code, and I can't see any reason why it would keep sending ( or receiving).

If you have a ethernet connection to your Mac, it is quite easy to check. Enable sharing over wifi of your ethernet connection. Install little snitch, it will run in demo mode for three hours after every boot. Turn off the data connection on the test device and connect it to your mac over wifi.

This will allow you to see any network access your test device is making.

If this isn't possible, you can also run your app in the simulator as the network side should be the same, so you should be able to check.

There are also a ton of other tools to track network activity, but I think little snitch is the easiest to use.