Traffic can be sent to a single network host, all hosts on a subnet, or a select grouping of hosts that requested to receive the traffic. These traffic types include unicast, broadcast, multicast, and anycast.
Older routing protocols, such as RIPv1 and IGRP (the now-antiquated predecessor to EIGRP), used broadcasts to advertise routing information; however, most modern IGPs use multicasts for their route advertisements.
BGP establishes a TCP session between peers. Therefore, unicast transmissions are used for BGP route advertisement.
Most network traffic is unicast in nature, meaning that traffic travels from a single source device to a single destination device. Figure 1-8 illustrates an example of a unicast ...