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Zorluk: OrtaIPv6 Address Types and EUI-64

A network administrator is inspecting a host connected to a Cisco switch. The host network interface has a hardware MAC address of `5254.0012.3456`. Assuming IPv6 stateless autoconfiguration uses the standard IEEE EUI-64 format, what is the resulting 64-bit interface identifier?

Cevap: 5054:00ff:fe12:3456 / 5054:00FF:FE12:3456 / 5054:ff:fe12:3456 / 5054:FF:FE12:3456

Cevap

5054:00ff:fe12:3456
To derive the EUI-64 interface identifier from MAC address `5254.0012.3456`:
1. Split the MAC address: `52:54:00` and `12:34:56`.
2. Insert `FFFE` in the middle: `5254:00FF:FE12:3456`.
3. Invert the 7th bit of the first byte: `0x52` (`0101 0010` in binary) becomes `0x50` (`0101 0000` in binary).

Combining these operations yields the final 64-bit interface identifier `5054:00ff:fe12:3456`.

Adım Adım Çözüm

1
Split the 48-bit MAC address into two 24-bit halves.
Left half: `52:54:00`, Right half: `12:34:56`
EUI-64 insertion occurs directly between the OUI and the vendor-assigned NIC portion.
2
Insert the 16-bit hex value `FFFE` into the middle.
`5254:00FF:FE12:3456`
Inserting `FFFE` expands the 48-bit MAC address into a 64-bit structure.
3
Invert the 7th bit (Universal/Local bit) of the first byte.
First byte `0x52` in binary is `0101 0010`. Inverting the 7th bit yields `0101 0000`, which is `0x50` in hex.
IEEE EUI-64 standards dictate that the 7th bit is flipped (0 becomes 1 for local uniqueness, 1 becomes 0 for universal).
4
Assemble the final 64-bit interface identifier in standard IPv6 hexadecimal notation.
`5054:00ff:fe12:3456`
Combines the modified first byte, remaining MAC components, and inserted `FFFE` into 16-bit colon-separated fields.

Anahtar Kavram

EUI-64 Interface Identifier Derivation
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Konular

IPv6 Address Types and EUI-64

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