I wanted to know that how to do passively monitor network traffic using C# in Windows phone? Suppose I browse as www.facebook.com in IE then I need to get notification in my application. So, please any help would be appreciated.
Thanks.
Unfortunately you cannot access that level of information on Windows Phone. Windows Phone is a managed platform where each app is kept inside its own boundary.
Each time an app require access to information outside that boundary a specific permissions need to be assigned to the app. In Windows Phone this called App Capabilities and a full list of them can be found here: https://msdn.microsoft.com/en-us/library/windows/apps/jj206936(v=vs.105).aspx
As you see there are a lot of things you can get access to. But low-level networking is not one of them.
It is not possible to break out of the box in which the app as executing and it is not possible to deploy "native" code running outside the box. This is actually the whole purpose of the app paradigm on Windows Phone, Windows 8/10, iPhone and iPad. By making sure no app can gain low-level access to your device you are protected from viruses, spyware, etc.