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Zorluk: ZorIPv6 Address Types and EUI-64

A network engineer is deploying IPv6 on a Cisco router interface with the burned-in MAC address `b496.910a.bcde`. The interface is enabled to automatically formulate its link-local address using standard EUI-64 formatting. What complete, compressed link-local IPv6 address will be generated on this interface?

Cevap: fe80::b696:91ff:fe0a:bcde / FE80::B696:91FF:FE0A:BCDE / fe80:0000:0000:0000:b696:91ff:fe0a:bcde / FE80:0000:0000:0000:B696:91FF:FE0A:BCDE

Cevap

fe80::b696:91ff:fe0a:bcde
The MAC address `b496.910a.bcde` consists of octets `b4`, `96`, `91`, `0a`, `bc`, `de`. Inverting the 7th bit of `b4` (binary `1011 0100`) gives binary `1011 0110` (hex `b6`). Inserting `fffe` into the midpoint between `91` and `0a` creates the 64-bit interface ID `b696:91ff:fe0a:bcde`. Combining this with the IPv6 link-local prefix `fe80::/64` yields `fe80::b696:91ff:fe0a:bcde`.

Adım Adım Çözüm

1
Split the 48-bit MAC address into two 24-bit halves.
Left half: `b4-96-91`, Right half: `0a-bc-de`.
The 64-bit interface identifier is constructed by inserting a 16-bit hex delimiter into the middle of the 48-bit MAC address.
2
Invert the Universal/Local (U/L) bit (the 7th bit of the first byte).
The first byte `b4` (hex `1011 0100` in binary) becomes `1011 0110` (hex `b6`).
In EUI-64 conversion, the 7th bit (U/L bit) of the first byte must be inverted (0 becomes 1 for globally unique MAC addresses).
3
Insert the 16-bit hexadecimal string `FFFE` between the two halves.
The 64-bit interface identifier becomes `b696:91ff:fe0a:bcde`.
Inserting `FFFE` expands the 48-bit MAC address into a valid 64-bit EUI-64 interface identifier.
4
Prepend the IPv6 link-local prefix (`fe80::/64`).
The full link-local address is `fe80::b696:91ff:fe0a:bcde`.
IPv6 link-local addresses use the reserved prefix `fe80::/10` with standard interface configuration defaulting to `fe80::/64` followed by the 64-bit EUI-64 interface ID.

Anahtar Kavram

IPv6 EUI-64 Link-Local Address Derivation
Tahmini Süre:2m 0s
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Konular

IPv6 Address Types and EUI-64

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