EUI-64

EUI-64 or Modified EUI-64 are often used as the lower 64 bit of a IPv6 Address.

EUI-64

EUI-64^[1] or Extended Unique Identifier is a 64 bit Global Identifier administered by IEEE^[2]

Examples of use

FireWire^[3] and in IPv6 as least significant 64 bits in Link-Local and Global Unicast if Stateless Autoconfiguration. (Except Systems that will choice a Random page fx. Windows 7)

EUI-48

EUI-48^[4] or Extended Unique Identifier is a 48 bit Global Identifier administered by IEEE^[5].

Examples of use

Ethernet MAC addresses is a example of EUI-48 usage. Other examples of technologies that use EUI-48 are Bluetooth and 802.11 Wireless Networks.

IPv6 Modifed EUI-64 Address

Understanding the MAC-Address

The MAC-Address is divided into two parts.

The first 24 bits identifies the manufacturer and are called the OUI
1. The OUI is administered by IEEE^[2]
The last 24 bits identifies Extension Identifier or NIC
1. The manufacturer can use this field as serial-number

The MAC-Address is Global Unique and has two flag in its first octet. (Byte)

bit 1: Unicast or Multicast
- The MAC 'broadcast' address FF:FF:FF:FF:FF:FF is really a Well-Known link-local Multicast address used by for example IPv4 ARP and DHCP.
bit 2: Globally or locally administered. When bit 2 is 0 the Global Unique IEEE^[2] identifier is used. When bit 2 is 1 it's a Local generated address.

Generating the Modified EUI-64

When generating a modified EUI-64 as the 64 lower bits of a IPv6 Address the hosts EUI-48 (MAC-Address) is expanded to 64 bits by inserting FF:FE between the OUI and the Extension Identifer or NIC.

References

[1] ttp://standards.ieee.org/develop/regauth/tut/eui64.pdf

[IEEE-2] 2.0 ^2.1 ^2.2 http://www.ieee.org/index.html

[3] ttp://en.wikipedia.org/wiki/IEEE_1394_interface

[4] ttp://standards.ieee.org/develop/regauth/tut/eui48.pdf

[5] ttp://www.ieee.org/index.html

[1]

[2]

[3]

[4]

[5]