Network Link Conditioner allows Mac and iOS devices to accurately and consistently simulate adverse networking environments.(just don’t forget to turn it off after you’re done testing!

The Network Link Conditioner can change the network environment of the iOS Simulator according to one of the built-in presets:

  • EDGE
  • 3G
  • DSL
  • WiFi
  • High Latency DNS
  • Very Bad Network
  • 100% Loss

Refer from http://nshipster.com/network-link-conditioner/

1、Enable Develoopment mode on iOS with Xcode

  • Connect your iPhone or iPad to your Mac

  • In Xcode, go to Window > Devices and Simulators(⇧⌘2)

  • Select your device in the sidebar

  • Click “Use for Development”

c. And add or edit profiles.