- Broadcast Domain
- A broadcast domain consists of the set of all hosts and physical network segments that will hear broadcast frames transmitted at the data link layer by one of the device interfaces within the domain.
What is a Broadcast?
A broadcast (in the context of Broadcast Domains on 802 based WiFi/Ethernet/FDDI networks) is any data link layer frame whose destination address is set to all ones, indicating that it should be delivered to all hosts on the local area network (LAN). The destination and source addresses in data link layer frames are 48 bits long and usually presented in hexidecimal, so the destination address in a broadcast frame is set to FFFFFFFFFFFF. Depending on the vendor, that will be displayed as FFFFFFFFFFFF, or FFFF.FFFF.FFFF or FF:FF:FF:FF:FF:FF.
Why Are Broadcasts Used?
Broadcasts are used to announce the existence of devices or services or to "look up" devices and network services at the datalink layer.
How do you send a Broadcast?
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 frame, the host-specific portion of the destination address is set to all ones.
This broadcast frame is sent to all hosts on the network using the all hosts broadcast address (FFFF.FFFF.FFFF).
Protocols that Use Broadcast Frames
- Collision Domain
- Network Segment
- Media Access Control Addresses (MAC Addresses)
- Ethernet Frame Format