The defining feature of IPv6 is increased address space in comparison to IPv4. IPv6 also improves Internet capabilities in numerous areas, as outlined in this section.
IP address size increases from 32 bits in IPv4 to 128 bits in IPv6, to support more levels of addressing hierarchy. In addition, IPv6 provides many more addressable IPv6 systems. For more information, see IPv6 Addressing Overview.
The IPv6 Neighbor Discovery (ND) protocol facilitates the autoconfiguration of IPv6 addresses. Autoconfiguration is the ability of an IPv6 host to automatically generate its own IPv6 address, which makes address administration easier and less time-consuming. For more information, see IPv6 Address Autoconfiguration.
The Neighbor Discovery protocol corresponds to a combination of these IPv4 protocols: Address Resolution Protocol (ARP), Internet Control Message Protocol (ICMP), Router Discovery (RDISC), and ICMP Redirect. IPv6 routers use Neighbor Discovery to advertise the IPv6 site prefix. IPv6 hosts use Neighbor Discovery for various purposes, which include soliciting the prefix from an IPv6 router. For more information, see IPv6 Neighbor Discovery Protocol Overview.
The IPv6 header format either drops or makes optional certain IPv4 header fields. This change keeps the bandwidth cost of the IPv6 header as low as possible, despite the increased address size. Even though IPv6 addresses are four times longer than IPv4 addresses, the IPv6 header is only twice the size of the IPv4 header.
Changes in the way IP header options are encoded allow for more efficient forwarding. Also, IPv6 options have less stringent limits on their length. The changes provide greater flexibility for introducing new options in the future.
Many critical Oracle Solaris network services recognize and support IPv6 addresses, for example:
Name services, such as DNS, LDAP, and NIS. For more information on IPv6 support by these name services, see System Administration Guide: Naming and Directory Services (DNS, NIS, and LDAP).
Authentication and privacy applications, such as IP Security Architecture (IPsec) and Internet Key Exchange (IKE). For more information, see Part IV, IP Security.
Differentiated services, as provided by IP Quality of Service (IPQoS). For more information, see Part VII, IP Quality of Service (IPQoS).
Failover detection, as provided by IP network multipathing (IPMP). For more information, see Part VI, IPMP.
In addition to this Part, you can obtain information about IPv6 from the sources that are listed in the following sections.
Many RFCs are available regarding IPv6. The following table lists the major IPv6 articles and their Internet Engineering Task Force (IETF) web locations as of this writing.
Table 3-1 IPv6–Related RFCs and Internet Drafts
The following web sites provide useful information about IPv6.
Table 3-2 IPv6–Related Web Sites