Next Generation Internet 4over6 soft line Tunnel transition technology (1)

After more than 20 years of rapid development, the Internet based on IPv4 protocol has achieved great success in the world. However, with the continuous growth of the Internet scale, new demands, and new business development, the IPv4-based network environment is hard to cope with. The rapid expansion of the network scale highlights a series of serious problems of IPv4, including insufficient address resources, insufficient routing scalability, and end-to-end feature damage caused by Network Address Translation (NAT) technology [1.

IPv6 [2] is a basic network protocol that replaces IPv4 in the Next Generation Internet. Because IPv6 is not compatible with IPv4, the Internet is faced with heterogeneous routing, scalability, status maintenance, and other issues during the transition from IPv4 to IPv6. In addition, because most network resources, services, and applications are still implemented based on IPv4, end users are still dependent on IPv4, and Internet service providers (ISPs) have some inertia for IPv6 upgrade, as well as insufficient IPv6 support for network devices, especially access network devices, it is foreseeable that IPv4 and IPv6 will coexist for a long period of time. During the coexistence of the two, how to quickly transition the entire network to IPv6, especially the access network, has become the key to restricting the development of the next generation Internet.

For IPv6 transition, many international technical solutions have been proposed [3]. These solutions are classified by technical ideology and can be divided into tunneling and translation technologies [4-5]. Based on the concept of tunnel transition, this paper proposes an IPv6 tunnel transition framework system for the entire network, as well as the 4over6 soft-line tunnel technology applicable to the transition between the backbone network and the access network. At present, the 4over6 soft-line Tunnel transition scheme and related technologies have formed three international standards in the IETF of the international Internet Standardization Organization, including RFC4925, RFC5565, and rf120047, the China Communications Standardization Association has formed two standards for the China communications industry.

1. network-wide IPv6 tunnel Transition Framework and Policy

The IPv6 transition technology solution for the entire network needs to meet the following requirements [6]:

(1) maintain the end-to-end feature, which is a basic requirement for achieving two-way communication between the terminal node and the Internet.

(2) Maintaining the scalability of heterogeneous networks, that is, the independence and scalability of IPv4 and IPv6 routes, this is an important guarantee for smooth IPv6 transition when the existing IPv4 network is minimized during the transition period.

(3) transparent presentation of upper-layer mobile applications, which is the key to maintaining existing IPv4 applications during the IPv6 transition period and ensuring a good network experience for users.

Network-wide IPv6 tunnel transition [7] can be divided into backbone network IPv6 transition and access network IPv6 transition based on different network levels, as shown in tunnel transition framework 1. The backbone network connects to the ISP network up, other backbone networks at the same level, and the access network down. The access network connects to the backbone network to provide access to different types of users. There are several border routers (BRS) connected to the edge routers (PES) on the adjacent side of the access network and the backbone network. The transition of the backbone network tunnel requires that the PE be upgraded to the dual-stack mode. The PE uses tunnels to provide transparent transmission for groups with different backbone network address clusters. Tunnel transition requires both the BR and the user-side edge device (CE) to maintain the dual stack. CE creates a tunnel for the group of different address clusters of the access network and sends it to the BR, in this way, the CE and BR use tunnels to provide transparent transmission for groups with heterogeneous access network address Clusters [8].

Figure 1 network-wide IPv6 tunnel Transition Framework