Broadcasts in IPv4 networks are quite common, and these layer 3 broadcasts will be sent over layer 2 broadcasts. Every time a layer 3 device sends a broadcast to the network (destined to the subnet's broadcast address; refer to Chapter 10, Network Layer Protocols and Operations, for more information), it will be converted to all fs destination MAC addresses.

There are several families of broadcasts that you will see in IP-based networks. Some of them are as follows:

• TCP/IP-based network protocols, such as ARP requests, DHCP requests, and others
• Network protocols, such as NetBIOS Name Service (NBNS) queries, NetBIOS Server Message Block (SMB) announcements, Network Time Protocol (NTP), and others
• Applications that send broadcasts, such as Dropbox, Microsoft network load balancing, and others

In IPv6, we don't have broadcasts, but we have unicasts, multicasts, and anycasts. Since the protocol works with multicasts for discovery mechanisms, announcements, and other mechanisms, we will see a lot of them.