Development Trend of Access Network Technology

China's access network technology is still developing very rapidly. At the same time, IPv6 networks have already entered the eyes of people. Many people may not understand the problems of IPv4-to-IPv6 transition. It does not matter, after reading this article, you must have gained a lot. I hope this article will teach you more things. During the transition from a mobile network to a mobile IPv6 network, IPv4 networks and services will coexist with IPv6 for a long time, and many services still need to run on IPv4 networks for a long time, in particular, IPv6 cannot provide global connections immediately. Many IPv6 communications have to be transmitted over IPv4 networks. Therefore, the transition mechanism is very important and requires special attention and attention from the industry. The transition from IPv4 to IPv6 is gradual and controllable. The transition period will be quite long, and the Network/terminal devices must support both IPv4 and IPv6, the ultimate goal is to make all business functions run on the IPv6 platform.

1. transition from IPv4 to IPv6

There are three methods to transition from IPv4 to IPv6: the dual-protocol stack of network elements/terminals, the tunnel access network technology in the network, and the translation mechanism. The dual-protocol stack and tunnel access technology are the main methods, while the translation mechanism is inefficient and only used for communication between elements of different IP versions.

(1) network elements and IPv4/IPv6 Dual-protocol stack on mobile terminals are very important transitional mechanisms. From the network aspect, network devices (such as GGSN) the implementation of Dual-protocol stack for IPv4 and IPv6 Access Points and the completion of the IPv6-in-IPv4 tunnel is crucial, in addition to the operator's IP network and public Internet edge of the edge router should also be a dual-Stack Router. From the perspective of mobile terminals, we need to use a dual-protocol stack to access IPv4 and IPv6 services without the translation mechanism on the network.

(2) tunneling technology, such as encapsulating IPv6 data packets in IPv4 data packets and unencapsulating them at the other end of the tunnel, is also a very important method of transition, tunnel technology requires IPv4/IPv6 Dual-protocol stack functionality on both encapsulated and unencapsulated nodes. Tunnel technology can be divided into automatic and manual configuration. The manually configured tunnel access network technology is manually configured to a specific IPv4 address at the tunnel endpoint. For the automatic tunnel access network technology, encapsulation is automatically completed on the encapsulated router/host. The IPv4 address at the tunnel end is included in the packet whose destination address is IPv6 address, such as "6to4" tunnel technology.

(3) IPv4-IPv6 protocol translator on the Network: translator is the middleware between pure IPv4 host and pure IPv6 host, so that the two hosts do not need to modify any configuration can achieve direct communication between each other, the usage of the translator is transparent to mobile terminals, and the header conversion is an important translation mechanism. In this way, the header label of an IPv6 packet is converted to the header label of an IPv4 packet, or, in turn, IPv4 is converted to IPv6, and verification is adjusted or recalculated when necessary. NAT/PT (Network Address Translator/Protocol Translator) is a method using this mechanism.

The address/protocol translator must be used to convert the header of the IP data packet. The problem is that the end-to-end service (such as the end-to-end IPSec) is damaged, and NAT/PT may become the bottleneck of network performance, it is possible to limit the capacity and scalability of the business platform. The use of the address/protocol translator in the network or other transitional methods is mainly determined by the network operator. Generally, the translator is recommended only when the IP versions of the two communication nodes are different.

2. transition from IPv4 to IPv6

(1) Phase 1: The network has a separate IPv6 Island. The connection between them is achieved through automatic or manual configuration of the "IPv6 in IPv4" tunnel on the IPv4 network. At this stage, the vast majority of IPv6 services provided to mobile users are provided by the carrier's Intranet, other IPv6 services are implemented through configuration/automatic tunnel on IPv4 networks. traditional IPv4 services can provide IPv4 or dual-protocol stack terminals. There is still NAT on the network of the carrier, and the public IPv4 address is scarce by allocating a temporary address. A translator (such as a NAT-PT) can also be installed on the carrier's network to complete translation conversion between IPv4 and IPv6 protocols.

(2) Phase 2: IPv6 has been widely deployed and has a large number of services implemented on the IPv6 platform. However, IPv6 cannot be fully connected yet, sometimes the IPv4 network tunnel access technology is still needed to connect to IPv6 nodes.

In this phase, all new services are implemented on the IPv6 platform, thus accelerating the deployment of IPv6. From the development trend of IPv6, mobile networks will be the first to enter this development stage. At this time, a large number of traditional IPv4 services still exist, and many mobile nodes have installed IPv4/IPv6 Dual-protocol stacks.

(3) Stage 3: IPv6 has gained a leading position. IPv6 has achieved global connectivity and all services are running on the IPv6 platform, at this time, the dual-protocol stack function or address/protocol translation mechanism is no longer required, which makes the network structure simpler and network maintenance easier.