What occurs when a host does not have the MAC address but has the IP address of a destination device?

What occurs when a host does not have the MAC address but has the IP address of a destination device?

• A. The host generates an ARP broadcast
• B. The host sends a request to the server
• C. The host ignores the packet
• D. The host contacts the DHCP server

Answer: (A)

When a host has an IP address for a destination device but does not have the corresponding MAC address, the host must determine that MAC address in order to send frames at the data link layer. This process is managed through the Address Resolution Protocol (ARP). To resolve the MAC address, the host generates an ARP broadcast. This broadcast is sent to all devices on the network segment, asking "Who has IP address X.X.X.X? Tell me your MAC address." The device that owns that IP address replies with its MAC address, allowing the originating host to build the necessary Ethernet frame for communication. This method is essential because the Internet Protocol operates at the network layer, where it uses IP addresses, while MAC addresses are used at the data link layer for actual frame delivery. Therefore, an ARP broadcast is a standard mechanism that facilitates the mapping of IP addresses to MAC addresses crucial for communication on a local network.

When a host has an IP address for a destination device but does not have the corresponding MAC address, the host must determine that MAC address in order to send frames at the data link layer. This process is managed through the Address Resolution Protocol (ARP).

To resolve the MAC address, the host generates an ARP broadcast. This broadcast is sent to all devices on the network segment, asking "Who has IP address X.X.X.X? Tell me your MAC address." The device that owns that IP address replies with its MAC address, allowing the originating host to build the necessary Ethernet frame for communication.

This method is essential because the Internet Protocol operates at the network layer, where it uses IP addresses, while MAC addresses are used at the data link layer for actual frame delivery. Therefore, an ARP broadcast is a standard mechanism that facilitates the mapping of IP addresses to MAC addresses crucial for communication on a local network.