In a MAC address, what designation is given to the first 3 bytes and what does it designate?

In a MAC address, what designation is given to the first 3 bytes and what does it designate?

• A. MAC Address Checksum
• B. Vendor Specific Extension
• C. Network Access Control Identifier
• D. Organizational Unique Identifier (OUI) designating manufacturer

Answer: (D)

The first three bytes form the Organizationally Unique Identifier, assigned by IEEE to a hardware manufacturer. This portion identifies which company produced the network interface card. The remaining three bytes are used by that manufacturer to assign a unique identifier to a specific device, making the complete 48-bit MAC address unique. Other terms listed don’t apply to this part of the MAC address, so they don’t designate the vendor.

The first three bytes form the Organizationally Unique Identifier, assigned by IEEE to a hardware manufacturer. This portion identifies which company produced the network interface card. The remaining three bytes are used by that manufacturer to assign a unique identifier to a specific device, making the complete 48-bit MAC address unique. Other terms listed don’t apply to this part of the MAC address, so they don’t designate the vendor.