Traditionally, we have been that defense in depth is the best practice approach if we want to secure our premises from security breach. However, I recently read about DoD's Joint information environment (JIE) and one component talks about single security architecture. However, after reading up a bit, I still could not grasp what the JIE actually is and what SSA is. Can you simplify JIE and SSA? Is it about using the cloud? What is the advantage in moving into JIE architecture instead of defense in depth?
If I look at a presentation about the topic it does not look like replacing defense in depth, but replacing a heterogeneous environment containing lots of different mostly independent and sometimes incompatible security solutions with a more structured environment where all parts work together to better detect and deal with the risks. It still contains defense in depth, i.e. the idea is not to restrict the risk management to a single perimeter. But the major point is that the different security layers now work with each other so that information collected at one layer might be used to optimize protection at another layer.
Example: different layers detect different kind of suspicious behavior. While each of these information separately is not enough to detect an advanced attack, it could be detected by combining the information.