The section invokes the most important function of a routing protocol – to dynamically adapt to network changes and choose the best path in response. Devices running dynamic routing protocols communicate with each other and exchange reachability information.
It is ideal to run a single IGP on the campus/enterprise network infrastructure to minimize the complexity of maintaining distribution points between multiple routing protocols which an increase risk of misconfiguration, which lends to sub-optimal routing or black holes.
Obviously, on a WAN edge where the carrier requires an EGP like BGP, some redistribution is necessary. The point is to avoid running OSPF and EIGRP on the same enterprise network.
Stuck-in-Active: Journal of an IT-Network Administrator 