I've built a great many large scale ISP and Data Center networks in the past.
As you know many many years ago BGP metrics became inefficient in making good routing decisions. So in the early 2000's companies began to come out with Intelligent Routing appliances that would "learn" traffic destinations and calculate latency/loss/jitter to and from destinations, then use that calculation to determine best path. Then best path would be injected into route table. I have been out of touch for the last few years. I assume that calculating traffic decisions has become even more complex, even down to the application layer. That is how I learned about Cisco NBAR2 and Cisco Adaptive Intelligent Routing AIR. Anyway, what does Cisco provide today to help ISP and Data Center routers do performance based routing/intelligent routing?