NCS5500 / NCS5700: Compatible or Native modes
Before going into the details of IOS XR 7.3.1, we take 10 minutes to explain the two operational modes of the Cisco NCS5500 / NCS5700: Compatible or Native.
In a nutshell, one is to guarantee backward compatibility between multiple generation of line cards in the same chassis (Jericho, J+ and J2) while the other will be enabled with systems exclusively made of Jericho2 and capable to use the whole capabilities of the NPU.