What defines a broadcast domain in a network?

• A. The set of devices sharing the same collision domain.
• B. The set of devices to which broadcast frames are forwarded; routers segment broadcast domains.
• C. The set of devices using the same IP address.
• D. The set of devices connected to the same switch port.

Answer: (B)

Broadcast domains are the group of devices that receive the same broadcast frames. When a device on a network sends a broadcast, every device in its broadcast domain should see it. Layer 2 switches forward broadcasts to all ports within the same VLAN, so the VLAN defines the broadcast domain. Routers don’t forward broadcasts by default, which is why they segment broadcast domains. This makes the boundary a result of forwarding behavior for broadcast frames, not just physical connections or IP addresses.

So, the set of devices to which broadcast frames are forwarded, with routers breaking up those boundaries, best captures what defines a broadcast domain.