Configure an IPv6 Router Interface

In this article we will discuss Configure an IPv6 Router Interface, will make brief discussion on Configure an IPv6 Router Interface, In last article we discuss about Configure an IPv4 Router Interface.

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 is the use of ipv6 in place of ip in commands.

An IPv6 interface must be:

  • Configured with IPv6 address and subnet mask – Use the ipv6 address ipv6-address/prefix-length [link-local | eui-64] interface configuration command.
  • Activated – The interface must be activated using the no shutdown command.

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:

  • ipv6 address ipv6-address/prefix-length – Creates a global unicast IPv6 address as specified.
  • ipv6 address ipv6-address/prefix-length eui-64 – Configures a global unicast IPv6 address with an interface identifier (ID) in the low-order 64 bits of the IPv6 address using the EUI-64 process.
  • ipv6 address ipv6-address/prefix-length link-local – Configures a static link-local address on the interface that is used instead of the link-local address that is automatically configured when the global unicast IPv6 address is assigned to the interface or enabled using the ipv6 enableinterface command. Recall, the ipv6 enable interface command is used to automatically create an IPv6 link-local address whether or not an IPv6 global unicast address has been assigned.

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

  • 2001:0DB8:ACAD:0001:/64 or equivalently 2001:DB8:ACAD:1::/64
  • 2001:0DB8:ACAD:0002:/64 or equivalently 2001:DB8:ACAD:2::/64
  • 2001:0DB8:ACAD:0003:/64 or equivalently 2001:DB8:ACAD:3::/64

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 have an IPv6 address manually configured, 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.

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