Figure 1 shows the format of an IPv6 link-local address.  The figure highlights the first ten binary bits set to 1111111010, which is FE80::/10 ten. The remaining 54 bits in the prefix are normally set to zero. The 64 bit interface ID can be derived either through EUI-64 or a randomly generated 64-bit number. Figure 2 shows two Windows command line windows. Both windows show the “ipconfig” command output. In the top window, the link-local address was generated using EUI-64. In the bottom window, the link-local address was created using a randomly generated 64-bit number for the interface ID. Figure 3 shows the output on a router for the “show interface gigabitethernet 0/0” command. The MAC address, fc99.4775.c3e0, is highlighted. The second command entered is “show ipv6 interface brief”. Output from this command verifies that the router is using the same link-local address on all three active IPv6 interfaces. The link-local address was generated using EUI-64.