CompTIA Network+ Exam Review

Answer - B - Of all the protocols listed here, IGRP and RIP version 1 allows classfull routing. Only EIGRP allows classless routing.

Key Takeaway: Classless routing protocols extend the standard Class A, B, or C IP addressing scheme by using a subnet mask or mask length to indicate how routers must interpret an IP network ID. They include the subnet mask, along with the IP address when advertising routing information. Subnet masks representing the network ID are not restricted to those defined by the address classes, but can contain a variable number of high-order bits. Such subnet mask flexibility enables you to group several networks as a single entry in a routing table, significantly reducing routing overhead. Common classless routing protocols include RIP v2, EIGRP, OSPF, and BGP.