Link-local addresses created using the EUI-64 format or in some cases, random interface IDs, make it difficult to recognize and remember those addresses. Because IPv6 routing protocols use IPv6 link-local addresses for unicast addressing and next-hop address information in the routing table, it is common practice to make it an easily recognizable address.
Configuring the link-local address manually provides the ability to create an address that is recognizable and easier to remember. As well, a router with several interfaces can assign the same link-local address to each IPv6 interface. This is because the link-local address is only required for local communications.
Link-local addresses can be configured manually using the same interface command used to create IPv6 global unicast addresses, but appending the link-local keyword to the ipv6 address command.
A link-local address has a prefix within the range FE80 to FEBF. When an address begins with this hextet (16-bit segment) the link-local keyword must follow the address.
The example in Figure 1 configures the same link-local address FE80::1 on the three R1 interfaces. FE80::1 was chosen to make it easy to remember the link-local addresses of R1.
A quick look at the interfaces as shown in Figure 2 confirms that the R1 interface link-local addresses have been changed to FE80::1.
Use the Syntax Checker in Figure 3 to configure and verify link-local address FE80::2 on R2, and the link-local address FE80::3 on R3.