Cisco Certified Network Professional 2025 – 400 Free Practice Questions to Pass the Exam

The purpose of the EUI-64 process in IPv6 is to convert a 48-bit MAC address into a 64-bit interface identifier, which is then used in the formation of an IPv6 address. This process plays a crucial role in the automatic process of address configuration, particularly for Stateless Address Autoconfiguration (SLAAC). It takes the Extended Unique Identifier (EUI) from the interface's MAC address and extends it to create a unique identifier that ensures each interface on a network can generate its own unique global unicast address.

The EUI-64 format takes a 48-bit MAC address, splits it into two 24-bit halves, inserts the hexadecimal value "FFFE" in between them, and flips the 7th bit of the first byte (which is responsible for indicating whether the address is universally or locally assigned). This results in a globally unique 64-bit identifier that can be appended to the 64-bit network prefix to create a complete IPv6 address. The use of EUI-64 enables devices to self-configure, facilitating plug-and-play networking.

In contrast, assigning a default gateway pertains to routing and does not involve address conversion; managing DHCP leases is related to the allocation and management of IP addresses but