Routing protocols can be classified into different groups according to their characteristics. Specifically, routing protocols can be classified by their:

For example, IPv4 routing protocols are classified as follows:

The classful routing protocols, RIPv1 and IGRP, are legacy protocols and are only used in older networks. These routing protocols have evolved into the classless routing protocols, RIPv2 and EIGRP, respectively. Link-state routing protocols are classless by nature.

Figure 1 displays a hierarchical view of dynamic routing protocol classification.

Figures 2 to 5 highlight the purpose, operation, and behavior of the various routing protocols.