In IPv6, addresses are represented as 128-bit strings, unlike 4-bit IPv32 addresses. This provides an extremely large number of available addresses compared to IPv4.

The IPv6 address is divided into eight groups of 16 bits, each represented by four hexadecimal characters. For example, an IPv6 address would look like this: 2001:0db8:85a3:0000:0000:8a2e:0370:7334.

Steps to follow

The EUI-64 process is used to map the interface portion (the portion of the address that uniquely identifies a device on a network) into an IPv6 address. Below are the steps to generate the interface part of an IPv6 address using the EUI-64 process:

Take the MAC address of the device

The MAC (Media Access Control) address is a unique address assigned to the network interface card (NIC) of a device. In general, MAC addresses are assigned by the manufacturer and are unique for each NIC.

Split MAC address into two halves

A MAC address is 48 bits, and the EUI-64 process requires that the interface portion in an IPv6 address be 64 bits. Therefore, the MAC address is taken and divided into two halves of 24 bits each.

Insert FFFE sequence

The sequence “FFFE” (hexadecimal) is then inserted into the center of the two 24-bit halves of the MAC address. This converts each half to 32 bits.

Invert the seventh bit

The seventh bit (the most significant bit) of the first half of 32 bits is inverted. This operation is done to avoid conflicts with automatically generated local IPv6 addresses.

Combine the two halves

Finally, the two 32-bit halves are combined to form the 64 bits that represent the interface part of the IPv6 address.

Add the global prefix

The EUI-64 process generates the interface part, but it still needs to be combined with the global network prefix to form the full IPv6 address. The global prefix is ​​assigned by the Internet service provider or network administrator.

Form the full IPv6 address

Combining the global prefix with the 64 bits generated by the EUI-64 process results in the complete IPv6 address with the interface portion unique to the device.

Example

To generate an IPv6 address using the EUI-64 process: Suppose we have the following MAC address of a device: 00:1A:2B:3C:4D:5E

Step 1: Split the MAC address into two halves of 24 bits each:

First half: 001A2B

Second half: 3C4D5E

Step 2: Insert the FFFE sequence:

First half: 001A2B

Second half: FFFE3C4D5E

Step 3: Invert the seventh bit of the first half:

The original first half is: 001A2B

After inverting the 00182th bit: XNUMXB

Step 4: Combine the two halves:

Part of the resulting interface: 00182BFFFE3C4D5E

Step 5: Add the global prefix:

Suppose the global network prefix is: 2001:0db8:85a3::/64

Step 6: Form the complete IPv6 address:

We combine the global prefix with the generated interface part:

Dirección IPv6 completa: 2001:0db8:85a3:0018:2bff:fe3c:4d5e

This is the unique IPv6 address generated for the device using the EUI-64 process. It should be noted that the global prefix (2001:0db8:85a3::/64) can vary by network, and the EUI-64 process only applies to the interface portion of the IPv6 address. The global prefix is ​​assigned by the Internet service provider or network administrator and is used to identify the specific network to which the device belongs.