- Broadcast Domain
- A broadcast domain is the set of all hosts and physical network segments that will hear the message when a particular protocol sends a brodcast transmission.
Types of Broadcast Domains
Layer 2 Broadcasts
Ethernet is a broadcast, multi-access networking protocol that has the capability to send a frame to all hosts on the network. When an ethernet device sends a broadcast, the host-specific portion of the destination MAC address is set to all ones.
Layer 3 Broadcasts
Internet Protocol addresses can be divided into groups of networks, subnetworks and hosts. When a broadcast is sent to all subnetworks, a router will forward the request. Internet Protocol can also send a broadcast to all hosts in a single IP subnet range, but this usually translates to a broadcast at Layer 2 on the local LAN.
Restricting Broadcast Domains
Routers, and to a limited extent, switches are used to segment networks and reduce or restrict broadcasts to the local network (LAN), or a network segment. Reducing broadcasts reduces the overall network load.
Why Are Broadcasts Used?