Apparently, there are several very distinct topics in routing which have the word “demand” in them. First, there is Cisco On-Demand Routing quasi-protocol, and then there are on-demand circuits which routing protocols must treat differently. Last but not least, the on-demand circuits are used for Routing Backup.
Internet Protocol Routing, nowadays commonly known as L3 Switching, is part of the process of forwarding an IP packet from Source to Destination. Interestingly, it happens more often then commonly understood: even on a common subnet we often need to make an IP routing decision.