What key element is included in the header of an Ethernet frame?

The inclusion of the source and destination MAC addresses in the header of an Ethernet frame is essential for the functioning of Ethernet networking. Each Ethernet frame carries a header that contains specific information necessary for the proper routing and delivery of data between devices on a local area network (LAN).

The source MAC address identifies the device that is sending the frame, allowing the recipient device to know where the data is coming from. Conversely, the destination MAC address specifies which device on the network should receive the frame. This addressing is crucial for ensuring that data is correctly delivered to the appropriate device within the same broadcast domain, facilitating communication between devices in a local network.

While other elements, such as IP addresses and checksums, are important in networking, they are not part of the Ethernet frame header specifically. IP addresses are relevant at the network layer and are used when packets need to be routed over broader networks beyond just the local segment. Checksums may be used for error-checking purposes but are not a fundamental component of the Ethernet frame header itself. Thus, the correct identification of source and destination addresses within the Ethernet frame header highlights the layer 2 functioning of Ethernet protocols.