For this discussion, read Guide to Increased Security in Industrial Control Systems Section B07-Create a multilayer defence (defence-in-depth) in industrial control systems 27 and then post your thoughts on the following topic:

Explain how using a layered approach to security is required to deal with today's advanced threats.

• Define what you feel is using a layered approach to security as it applies to Industrial Control Systems
• Provide an example of how having two layers of defense might be able to thwart an attack that would have been successful with only one layer
• Explain how perimeter defense systems and interior defense systems can combine to create a layered approach.