Being able to test different network conditions is important if your app performs any networking . The last thing you want is the user being stuck, or some functionality not working at all because the user is on a mediocre networking connection.
If you’re running :ion there is a built in utility that adds a new system preferences pane allowing you to set different network speeds, packet loss conditions and latency found under:
/Developer/Applications/Utilities/Network Link Conditioner/.
You’ll need to reboot after setting things up for your network limitations to take effect, or reload the settings by executing the command:
sudo launchctl load /system/library/launchdaemons/com.apple.networklinkconditioner.plist
Thanks to Use Your Loaf for the tip.
If you’re using Leopard there is a handy open source tool from Mike Schrag that will add a preferences pane allowing you to simulate different network speeds that can be found on Github here.
You can also directly use the command line you can use the Unix utility ipfw. A great Quora answer specifically on simulating different network conditions using ipfw can be found here.
Of course these settings will all only work in the iOS Simulator, but it’s still a great way to test things.