In this section we'll look at some of the aspects of configuring IPv6 routers. We'll begin with the configuration of routing advertisements sent to end hosts, as this is an important area of IPv6 operation that doesn't have an analogue in IPv4. After that we'll move on to the configuration of the inter-router protocols.
Router Advertisements, as discussed in Section 3.4.2 in Chapter 3, are a way of providing configuration information to hosts on your network. Usually you will not need to do much more than turn on router advertisements and your router will automatically advertise the IPv6 prefixes on the interfaces they have configured.
In some unusual situations you may want to adjust parameters. For example, if you run a wireless network or a dial-up network, then you may want to adjust the lifetimes of the prefixes to be short so that the nodes in the network deprecate them quickly after the router stops advertising them or the node moves out of wireless range. If you adjust the lifetime of a prefix, you may also want to adjust how often the prefix is advertised—the maximum time between advertisements should be less than the lifetime of the prefix to make sure it does not accidently become deprecated.
On Cisco's IOS you have to do very little to enable router advertisements—when you enable ipv6 unicast-routing and configure an IPv6 address on an interface, the router will begin to send advertisements and reply to solicitations. More ...