A broadcast domain is a logical part or division of a computer network. In a broadcast domain, all the nodes can be reached via broadcast at the datalink layer. Broadcast domains are located within a network or multi-network segment. Multi-network segments require a bridge, such as the networking device.
A broadcast domain member can also be any device or computer that is directly connected to the same switch or repeater. Networking devices, such as routers, are used to separate the boundaries of broadcast domains.
Techopedia explains Broadcast Domain
A broadcast domain provides high-level communication and reliability via a simple Ethernet connection. An assigned broadcast domain or destination receives addressed and transmitted data frames, which are detected by each node. However, data frames are only received by addressed nodes.
The best broadcast domain example is the virtual local area network (VLAN) in which multiple computers establish a broadcast domain via a virtual connection, they are not physically connected. A broadcast domain provides fast and reliable communication for offices in different locations.
One broadcast domain disadvantage is its tendency to drop Web data signals after reaching network router interface borders. Additionally, issues occur when a router links two or more broadcast domain networks, as described in the following example:
Let networks A and B be connected via a router. Network A, which has a Dynamic Host Configuration Protocol (DHCP) server, broadcasts Internet Protocol (IP) addresses to all attached computers. The DHCP service also tries to broadcast IP addresses to all computers attached to network B. However, the router drops incoming messages and network B’s computers do not get configured properly. Such issues occur in broadcast domains.
Current routers are manufactured with enhanced features, such as the no DHCP request blocking.