Several years have passed since RFC 791 for IPv4 was published. During this time, the requirements on the IP version used in the Internet have changed considerably. For example, the address space for 32-bit IPv4 addresses is almost depleted, in particularly because each mobile device, or even each household device, is expected to get its own IP address. In addition, the transmission technologies in fixed networks have so matured that packet errors have virtually been eradicated. These facts were motivation for further development beyond IPv4 to the protocol for the future Internet, resulting in IPv6. Since 1998, several standards have been introduced for IPv6, and the bases for these standards are the following RFCs:
RFC 2460 [HiDe98a] specifies IPv6.
RFC 2373 [HiDe98b] describes the architecture for IPv6 addressing.
