"Foundation Topics" covers the characteristics of the distance-vector routing protocols that the CCDA might choose from in a network design. RIPv1 is a routing protocol developed in the late 1980s; it was the only interior gateway protocol (IGP) at that time. RIPv2 provides enhancements to RIP, such as support for VLSMs.
The IGRP is an IGP developed by Cisco in the early 1990s that was not limited to the 15 router-hop constraint in RIP. EIGRP is a hybrid routing protocol that uses distance-vector metrics and link-state routing protocol characteristics.