What two protocols are used to determine the MAC address of a known destination device IP address (IPv4 and IPv6)?
In the case of IPv4, the Address Resolution Protocol (ARP) is used to determine the MAC address of a known destination device IP address.
When a device wants to communicate with another device on the same local network, it first checks if it has the MAC address of the destination device in its ARP cache. If it doesn’t have the MAC address, it sends an ARP request broadcast message to the network asking for the MAC address associated with the destination IP address. The device with the matching IP address will respond with its MAC address, and the requesting device will update its ARP cache with this information.
In the case of IPv6, the Neighbor Discovery Protocol (NDP) is used to determine the MAC address of a known destination device IP address. NDP provides functions similar to ARP, but is used in IPv6 networks. When a device wants to communicate with another device on the same network segment, it sends an NDP Neighbor Solicitation message to the all-nodes multicast address. The device with the matching IP address will respond with an NDP Neighbor Advertisement message, including its MAC address. The requesting device will then update its Neighbor Cache with this information.
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