Ethernet Protocol: Physical Addresses in Cisco Solutions

Physical Addresses in Ethernet Protocol


For what two purposes does the Ethernet protocol use physical addresses?



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A. B. C. D. E. F.


The Ethernet protocol is used to transmit data over local area networks (LANs) and relies on physical addresses, also known as MAC addresses, to identify devices at Layer 2 of the OSI model. These addresses are assigned by the manufacturer and are unique to each network interface card (NIC) or other network device.

The Ethernet protocol uses physical addresses for two main purposes:

  1. Uniquely identifying devices at Layer 2: Each device on an Ethernet network is assigned a unique MAC address, which is used to identify the device at Layer 2. When a device wants to send data to another device on the same network, it uses the MAC address of the destination device in the Ethernet frame header. The Ethernet protocol ensures that the frame is delivered to the correct device based on its MAC address.

  2. Allowing communication between different devices on the same network: The Ethernet protocol allows devices on the same network to communicate with each other using their MAC addresses. When a device wants to send data to another device on the same network, it broadcasts an Ethernet frame containing the destination device's MAC address. All devices on the network receive the frame, but only the device with the matching MAC address processes the data. This allows multiple devices to communicate on the same network without interfering with each other.

Answers B, C, D, and F are not correct because they do not accurately describe the purpose of physical addresses in the Ethernet protocol. Ethernet uses IP addresses for communication between devices on different networks (answer B) and does not use physical addresses to differentiate between Layer 2 frames and Layer 3 packets (answer C). Ethernet also does not establish a priority system based on physical addresses (answer D) and does not detect remote devices with unknown physical addresses (answer F).