A complete understanding of unicast and multicast IP addressing is required in order to design and implement robust IP networks. Concepts such as subnetting and Variable Length Subnet Masks (VLSM) should be mastered so that IP addressing plans make efficient use of your assigned address space. The concept, operation, and configuration of IP unicast routing protocols, RIP, IGRP, EIGRP, and OSPF, also need to be mastered because most multicast routing protocols rely on the underlying unicast routing configuration.