Daniel Dib comments on his blog:
It’s been five years since I started this blog! Time flies and a lot has happened since. Thanks for being along for the ride. What better way to celebrate than a blog post?
This post is going to be short and to the point.
Many of us run HSRP or VRRP. It is quite common to run it in a topology where you have dual routers and dual exits to the WAN and you don’t want to black hole your traffic.
Great look at using BFD from Daniel. This is how you should be creating failover scenarios.
Read more at: Using BFD to Track WAN Status and Change HSRP Priority