The final step in the EUI-64 process requires you to convert the first byte (two hex digits) from hex to binary, invert the seventh bit, and convert the bits back to hex. Inverting the bit means making it a 1 if it’s 0 and making it a 0 if it’s 1.////
The best way to master these EIU-64 interface IDs is to calculate some yourself. You may find out the burned-in address of a router interface using the show ipv6 interface command.///
You can then calculate the EUI-64 interface ID yourself using the MAC address of an interface. You may proceed to assign an EUI-64 address to the interface and verify if the interface ID calculated by the router matches the one you calculated. It can be a fun way to learn EUI-64 addressing for your CCNA exams. We will show you shortly how to assign EUI-64 addresses to router interfaces.
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In this example, we are going to assign EUI-64 address to FastEthernet0/0 of R1 using 2001:DB8:1:1::/64 as the 64-bit prefix.////
You may list the EUI-64 address using the show ipv6 interface brief command and compare the interface ID portion C000:1BFF:FE2C:0 calculated by the router to the one you calculated yourself from the burned-in address (C200.1B2C.0000)./////
The example shows EUI-64 address being assigned to a serial interface as well. Now, we know that serial interfaces do not have MAC addresses but the serial interface not only accepted the EUI-64 configuration but also got an EUI-64 address assigned. So, what’s really going on here. Cisco routers actually use the MAC address of the lowest-numbered router interface that does have a MAC to provide MAC address to serial and other interfaces that do not have MAC addresses of their own. In this example, R1 uses the MAC address of its FastEthernet0/0 interface to form the EUI-64 interface ID of the serial interface. ////
IPv6 Dynamic Address Configuration//////
IPv6 addresses configured statically are the more natural choice for router interfaces. However, routers can also be configured to use dynamically learned IPv6 addresses. Cisco routers can dynamically learn IPv6 addresses using: /////
Stateful DHCP (Dynamic Host Configuration Protocol)////
SLAAC (Stateless Address Autoconfiguration)/////
Both of these methods use the usual ipv6 address command with the appropriate keyword, though none of these two methods configures the actual IPv6 address.///