The IP protocol suite has been initallyi designed to provide best effort reachability among the nodes of a network or an inter-network. The goal was to design a set of routing solutions that would allow routers to automatically provide end-to-end connectivity among hosts. Also, the solution was meant to recover the connectivity upon the failure of one or multiple devices supporting the service, without the need of manual, slow, and error-prone reconfigurations. In other words, the requirement was to have an Internet that "converges" on its own. Along with the "Internet Boom", network availability expectations increased, as e-business emerged and companies started to associate loss of Internet connectivity with loss of customers... and money. So, Internet Service Providers (ISPs) relied on best practice rules for the design and the configuration of their networks, in order to improve their Quality of Service. The goal of this thesis is to complement the IP routing suite so as to improve its resiliency. It provides enhancements to routing protocols that reduce the IP packet losses when an IP network reacts to a change of its topology. It also provides techniques that allow ISPs to perform reconfigurations of their networks that do not lead to packet losses.