[Tip] Simulate various network conditions with "Network Link Conditioner"

Xcode provides a tool called Network Link Conditioner that can simulate various network conditions, including reduced bandwidth, high latency, DNS delays, packet loss, and so on. Before you ship any software that uses networking, you should install this tool, enable it, then run your software to see how it performs under real-world conditions.

Here are a few things to test:

• Make sure your software remains usable even with lousy bandwidth. Tune your bandwidth consumption as much as you can.
• Increase the latency to three or four seconds. Make sure that any user-initiated operation is delayed by only a few seconds, not by a few minutes.
• When the network connection drops packets, your software should continue to function, just more slowly.

Enabling Network Link Conditioner on iOS device:

- Step 1: Open Settings -> Select Developer -> Select Status in group name (Network link conditioner):

App Transport Security on iOS 9 and XCode 7 và cách tắt chức năng đó trên iOS 9.

Trên iOS 9, Apple giới thiệu 1 công nghệ mới để ngăn chặn ứng dụng sử dụng connection theo dạng HTTP để đảm bảo tính bảo mật cho ứng dụng trên iOS đó là App Transport Security (ATS). Mặc định những connection được viết dùng NSURLConnection, NSURLSession hay dùng những thư viện như (AFNetworking,...).