Exam 200-301 topic 1 question 33 discussion

C is correct! EUI-64 Process 01.Split Mac Address in to two ( 00:BB:CC | DD:11:22) 02. Insert FFFE Hexa in the middle Eg: 00:BB:CC:DD:11:22 --> 02BB:CCFF:FEDD:1122 03.Invert the 7th Bit of the MAC address (0 to 1)

EUI-64 (Extended Unique Identifier) is a method we can use to automatically configure IPv6 host addresses. An IPv6 device will use the MAC address of its interface to generate a unique 64-bit interface ID. However, a MAC address is 48 bit and the interface ID is 64 bit. What are we going to do with the missing bits? IPv6 MAC address vs Interface ID Here’s what we will do to fill the missing bits: We take the MAC address and split it into two pieces. We insert “FFFE” in between the two pieces so that we have a 64 bit value. We invert the 7th bit of the interface ID.

C. The seventh bit of the original MAC address of the interface is inverted is correct

C. The seventh bit of the original MAC address of the interface is inverted. In the process of generating an EUI-64 address, the 48-bit MAC address of the interface is taken, 16 bits are inserted (usually zeros), and then the seventh bit is inverted. This results in a 64-bit EUI-64 address used in IPv6 for interface identification.

C is correct seventh bit inverted

C IS CORRECT

Ref: Understanding IPv6 EUI-64 Bit Address - Cisco Community Post by SunilKhanna “… The IPv6 EUI-64 format address is obtained through the 48-bit MAC address. The MAC address is first separated into two 24-bits, with one being OUI (Organizationally Unique Identifier) and the other being NIC specific. The 16-bit 0xFFFE is then inserted between these two 24-bits for the 64-bit EUI address. IEEE has chosen FFFE as a reserved value which can only appear in EUI-64 generated from the an EUI-48 MAC address. … Next, the seventh bit from the left, or the universal/local (U/L) bit, needs to be inverted. This bit identifies whether this interface identifier is universally or locally administered. … Once the above is done, we have a fully functional EUI-64 format address. …”

a is wrong because its not random, its based on the MAC address b is wrong because FF:FE is inserted in the middle c is correct

C is correct

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.) C- correct

C is the answer

It can't be B due that the value that it's inserted in the Mac address is : FFFE. not FF80. We use FF80 when we want to create a multicast address.

FFFE goes in the middle, then the 7th bit is inverted

EUI-64

C is correct

Thanks "examcol"

Thanks