A network administrator configures a router interface to automatically generate a global u… — Cisco CCNA

A network administrator configures a router interface to automatically generate a global unicast IPv6 address using EUI-64 based on the network prefix $2001:\text{db8}:\text{acad}:1::/64$ . Given that the interface burned-in hardware MAC address is $1060.4\text{b}22.3344$ , which IPv6 address is dynamically assigned to the interface?

2001:db8:acad:1:1260:4bff:fe22:3344Answer
B
2001:db8:acad:1:1060:4bff:fe22:3344
C
2001:db8:acad:1:1260:4bff:ffff:3344
D
2001:db8:acad:1:0260:4bff:fe22:3344

Answer

The dynamically assigned IPv6 global unicast address is 2001:db8:acad:1:1260:4bff:fe22:3344.

The correct answer correctly applies both steps of EUI-64 interface identifier construction: inserting 0xFFFE into the middle of the MAC address (between 10-60-4B and 22-33-44) and inverting the 7th bit of the first byte (converting 0x10 binary 00010000 to 0x12 binary 00010010), yielding the interface ID 1260:4bff:fe22:3344 concatenated with prefix 2001:db8:acad:1::/64.

Step-by-Step Solution

Split the 48-bit MAC address into two 24-bit halves.

Left half is 1060.4b, right half is 22.3344.

EUI-64 generation requires dividing the MAC address to insert a 16-bit hex delimiter in the middle.

Insert the hex string FFFE between the two halves.

1060.4bff:fe22.3344.

Inserting FFFE expands the 48-bit MAC address into a 64-bit interface identifier.

Invert the 7th bit (Universal/Local bit) of the first byte.

First byte 0x10 (00010000 in binary) becomes 0x12 (00010010 in binary), making the interface ID 1260:4bff:fe22:3344.

IEEE EUI-64 format requires inverting the 7th bit to signify a universally administered address.

Combine the /64 network prefix with the generated 64-bit interface ID.

2001:db8:acad:1:1260:4bff:fe22:3344.

Concatenating the prefix 2001:db8:acad:1::/64 with the interface ID forms the complete IPv6 Global Unicast Address.

Key Concept

EUI-64 Interface Identifier Derivation

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