The term “internet” was adopted in the first RFC published on the TCP protocol (RFC 675: Internet Transmission Control Program, December 1974) as an abbreviation of the term internetworking and the two terms were used interchangeably. In general, an internet was any network using TCP/IP. It was around the time when ARPANET was interlinked with NSFNET in the late 1980s, that the term was used as the name of the network, Internet,being a large and global TCP/IP network. As interest in widespread networking grew and new applications for it were developed, the Internet’s technologies spread throughout the rest of the world. The network-agnostic approach in TCP/IP meant that it was easy to use any existing network infrastructure, such as the IPSS X.25 network, to carry Internet traffic. In 1984, University College London replaced its transatlantic satellite links with TCP/IP over IPSS.

Many sites unable to link directly to the Internet started to create simple gateways to allow transfer of email, at that time the most important application. Sites which only had intermittent connections used UUCP or FidoNet and relied on the gateways between these networks and the Internet. Some gateway services went beyond simple email peering, such as allowing access to FTP sites via UUCP or email. Finally, the Internet’s remaining centralized routing aspects were removed. The EGP routing protocol was replaced by a new protocol, the Border Gateway Protocol (BGP). This turned the Internet into a meshed topology and moved away from the centric architecture which ARPANET had emphasized. In 1994, Classless Inter-Domain Routing was introduced to support better conservation of address space which allowed use of route aggregation to decrease the size of routing tables.

IPv4/IPv6 Transition towards the Next Generation Internet

Although the basic protocol of the Next-Generation Internet (NGI) was defined as IPv6 over 10 years ago, the transition from the current IPv4-based Internet to IPv6-based NGI was still a long way to go. With the growth of Internet, it is predicted that IANA will exhaust its IPv4 address pool on 17-Jun-2011. Therefore, IPv6 networks and IPv6 applications will be widely used in the coming days. However, as different address families, IPv4 and IPv6 are difficult to inter-connect or even long-term coexist in the complex topology of Internet. After giving some basic IPv6 transition technologies in the literature, the talk will present the active work in IETF for IPv4/IPv6 coexistence. At last, the IPv6 progress in China will also be introduced.