WDAAgent Installtion on Real Device's Internet Requirement

Does WDAAgent Runner Installation on Real iOS Device Needs Internet Connection on Device or on the machine on which Appium server is running ?

We are using Appium 1.6.5
iOS: 10
XCode: 8.3.1

Issue : if Internet connection is not available, our script is unable to install WDAAgent on real iOS device,

Let me know if any detais are required to resolve the issue.