The interface ID created this way is known as the modified extended unique identifier 64 (EUI-64). Also, the 7th bit in the first byte is flipped to a binary 1. An interface ID is created by inserting the hex number FFFE in the middle of the MAC address of the network card.

The video (above) walks you step-by-step through this process, and also shows you how the calculated EUI-64 address can be used to calculate a router interface’s Link Local address (an IPv6 address used for communication only on the local network segment).The second part of an IPv6 unicast address (used to identify a host’s network interface) is usually a 64-bit interface identifier. Step #6: Convert these first eight bits back into hex:Ġ0000010 -> 02, which yields an EUI-64 address of 0215:2BFF:FEE4:9B60 Step #4: Convert the first eight bits to binary:

Step #3: Change the format to use a colon delimiter: Step #1: Split the MAC address in the middle: The objective is to calculate the corresponding EUI-64 address based on this MAC address. SCENARIO: Router R1 has a MAC address of 0015.2BE4.9B60 on its Fa 0/0 interface. The following steps walk you through a sample EUI-64 calculation:

This command tells the interface to use 2000:1:: as the network portion of the IPv6 address and to automatically calculate the 64-bit host portion of the IPv6 address.ĮUI-64 uses an interface’s MAC address as the basis of it’s calculation, even though we need a 64-bit host address, and a MAC address is only 48 bits in length. You could (in interface configuration mode of your Cisco IOS router) enter the command: For example, let’s say you have a router interface on the IPv6 network of 2000:1::/64. While you could manually configure the host bits for a router interface, a more efficient approach might be to automatically calculate those host bits using a 64-bit Extended Unique Identifier, known as EUI-64. A common approach is to use 64 bits to represent the network segment and 64 bits to represent the host on that network segment. An IPv6 address is 128 bits in length, and like an IPv4 address, it’s divided into prefix bits (representing the network segment) and host bits (uniquely identifying a host on that network segment).

Convert mac address to ipv6 link local