How can you determine if an Ethernet frame is intended only for the destination address?

In Ethernet networking, frames can be categorized based on their addressing to determine the intended recipient. An Ethernet frame contains a destination MAC address which indicates where the frame is supposed to go.

When examining the first octet of the destination MAC address, the last bit is particularly significant. If the last bit of the first octet is set to zero, it indicates that the address is unicast, meaning the frame is intended for a specific device on the network. This behavior aligns with the Ethernet addressing scheme where Ethernet addresses, expressed in binary form, can designate whether a frame is unicast, multicast, or broadcast.

In contrast, if the last bit is set to one, it signifies a multicast address, which allows a frame to be sent to multiple devices. This distinction is crucial for network communication, ensuring that data is correctly routed to its intended target rather than being broadcasted to all devices on the local segment.

Understanding this bit is foundational for networking, as it helps technologists manage communication efficiently within a network and prevent unnecessary data traffic. This makes the reasoning behind the correct choice clear and relevant in the context of distinguishing unicast Ethernet frames.