Routing protocols are clearly very important to the operation of the Internet, but in a sense they are a separate issue from the problems of how low-level IP should operate.
So, how has IPv6 changed routing protocols? Well, the most obvious change you need to make is to allow IPv6 prefixes to be included, rather than IPv4 addresses. In fact, this is generally the only significant change between the IPv4 and IPv6 versions of well-known routing protocols.
Perhaps the most interesting changes in routing caused by IPv6
are in routing policy—in other words, not
affecting the prefix processing per se, but affecting the
administrative acquisition and control of prefixes. The routes that
can be advertised into the IPv6 Internet's global routing table are to
be much more strictly controlled than in IPv4. For example, it is
hoped that people will not advertise individual
/48 prefixes, because (remember!) these
should be aggregated into a bigger block advertised by their ISP.
We'll talk more about the impact of this in Chapter 4.
For now, let's have a quick look at the routing protocols you're likely to encounter. First we'll deal with IGPs (Interior Gateway Protocols). An IGP is used to route within an organization. IGPs include protocols such as RIP, OSPF, and IS-IS. After IGPs we'll take a look at BGP, which is the main Exterior Gateway Protocol currently in use on the IPv6 Internet.
RIPng is defined in RFC 2080 and is very similar to its IPv4 forebear. It is designed for use ...