Configuring an IPv6 interface is similar to configuring an interface for IPv4. Most IPv6 configuration and verification commands in the Cisco IOS are very similar to their IPv4 counterparts. In many cases, the only difference uses ipv6 in place of ip in commands.

An IPv6 interface must be:

Note: An interface can generate its own IPv6 link-local address without having a global unicast address by using the ipv6 enable interface configuration command.

Unlike IPv4, IPv6 interfaces will typically have more than one IPv6 address. At a minimum, an IPv6 device must have an IPv6 link-local address but will most likely also have an IPv6 global unicast address. IPv6 also supports the ability for an interface to have multiple IPv6 global unicast addresses from the same subnet. The following commands can be used to statically create a global unicast or link-local IPv6 address:

In the example topology shown in Figure 1, R1 must be configured to support the following IPv6 network addresses:

When the router is configured using the ipv6 unicast-routing global configuration command, the router begins sending ICMPv6 Router Advertisement messages out the interface. This enables a PC connected to the interface to automatically configure an IPv6 address and to set a default gateway without needing the services of a DHCPv6 server. Alternatively, a PC connected to the IPv6 network can get its IPv6 address statically assigned, as shown in Figure 2. Notice that the default gateway address configured for PC1 is the IPv6 global unicast address of the R1 GigabitEthernet 0/0 interface.

The router interfaces in the example topology must be configured and enabled as shown in Figures 3 through 5.

Use the Syntax Checker in Figure 6 to configure the IPv6 global unicast addresses on router R2.