200-301 · Question #197
What is the expected outcome when an EUI-64 address is generated?
The correct answer is A. The seventh bit of original MAC address of the interface is inverted. The EUI-64 format interface ID is derived from the 48-bit MAC address by inserting the hexadecimal number fffe between the upper 3 bytes (OUI field) and the lower 3 vendor assigned bytes of the MAC address. Then, the seventh bit of the first octet is inverted. (In a MAC address,
Question
What is the expected outcome when an EUI-64 address is generated?
Options
- AThe seventh bit of original MAC address of the interface is inverted
- BThe interface ID is configured as a random 64-bit value
- CThe characters FE80 are inserted at the beginning of the MAC address of the interface
- DThe MAC address of the interface is used as the interface ID without modification
How the community answered
(58 responses)- A91% (53)
- B2% (1)
- C2% (1)
- D5% (3)
Explanation
The EUI-64 format interface ID is derived from the 48-bit MAC address by inserting the hexadecimal number fffe between the upper 3 bytes (OUI field) and the lower 3 vendor assigned bytes of the MAC address. Then, the seventh bit of the first octet is inverted. (In a MAC address, this bit indicates the scope and has a value of 1 for global scope and 0 for local scope; it will be 1 for globally unique MAC addresses. In the EUI-64 format, the meaning of this bit is opposite, so the bit is inverted.)
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