Before introducing ipv4-ipv6 transition technologies, let’s take a quick look at IPv4 and IPv6. What is IPv4? IPv4, also known as Internet Protocol Version 4, assigns a logical address to every network and every host on the Internet. An IP address is a 32-bit binary number that contains only 2^32 addresses. These addresses can be divided into five categories: A, B, C, D and E, while the more commonly used ones are only CLASS B and C, which have A more limited number of addresses. In addition to the rapid development of the Internet, IPv4 address pool has been exhausted in IANA on February 3, 2011. This has seriously restricted the development of the Internet. For IPv6, the next generation IP protocol used to replace IPv4, the length of IPv6 address is 128 bits, four times the length of IPv4 address. How many IPv6 addresses are there? And another line from the database looks at 3.402823669 × 10³⁸ addresses from 128 bits of IPv6. And another line looks at the number of addresses from every grain of sand in the world. If only the GirlFriend had been assigned, so that engineers could build better technology and xiaobian could have a GF.
IPv4 VS IPv6
IPv6 has many other advantages over IPv4 besides the abundant number of IP addresses.
Faster transmission speed
Fast, fast, very fast, which is what the Internet has long been looking for, and IPv6 is a fixed header, which doesn’t carry a bunch of long data like IPv4. The short header improves the efficiency of forwarding network data. In addition, the IPv6 routing table is smaller and has stronger aggregation capability, which ensures shorter data forwarding paths and greatly improves forwarding efficiency.
More secure means of transmission
Security While more and more sites are turning on SSL, there are still a large number of sites that do not use HTTPS. IPv4 does not force IPSec to encrypt data, resulting in the leakage of data transmitted in plaintext. IPv6 directly integrates IPSec to authenticate and encrypt data at the network layer, providing end-to-end data security for users and preventing data hijacking.
More mobile-friendly
Now mobile phones and other mobile devices can be said to have become an indispensable part of many people, IPv6 protocol can enhance the mobile features of mobile terminals, security features, routing features, while reducing the difficulty of network deployment and investment.
Plug and play
Compared with IPv4, IPv6 adds automatic configuration and reconfiguration technologies to automatically add, delete, and update INFORMATION such as IP addresses, improving IPv6 manageability.
Transition technology from IPv4 to IPv6
IPv6 was proposed in 1992, to now has been more than 20 years, the development of IPv6 technology has been very mature, then IPv4 can all switch to IPv6, the answer is definitely negative. Mainly because IPv6 is not an improvement on IPv4, IPv6 is a completely new protocol, which is a different network protocol at the link layer and cannot communicate directly. And it’s almost all IPv4 right now, so the transition could take a long time.
At present, IETF has set up a special working group to study the issue of IPv4 to IPv6 conversion, and has proposed many solutions, let’s introduce some of them first.
Double stack technique
IPv4 and IPv6 have similar network layer protocols, which are based on the same hardware platform and run both IPv4 and IPv6 stacks on the same host. Nodes with IPv4/IPv6 dual stacks are called dual-stack nodes. These nodes can send and receive IPv4 packets. It can also send and receive IPv6 packets. They can use IPv4 to communicate with IPv4 nodes or directly use IPv6 to communicate with IPv6 nodes. Dual-stack nodes contain both IPv4 and IPv6 network layers, but the use of transport layer protocols such as TCP and UDP is still single.
What are the pros and cons of dual-stack technology?
Advantages:
- High processing efficiency, no information loss
- Good interoperability and easy network planning
- Give full play to all the advantages of IPv6, smaller routing table, higher security, etc.
- Resource occupation, complex operation and maintenance.
Disadvantages:
- IPv4 cannot communicate with IPv6
- High requirements for network equipment, internal network transformation involves a relatively large, relatively long periodicity.
The tunnel technology
Tunneling encapsulates the header of a packet of another protocol in front of the original packet header, so that the packet can be directly transmitted over a network of different protocols. This mechanism is used to connect a single host or multiple hosts to an IPv6 site over an IPv4 network. Tunneling encapsulates IPv6 packets into IPv4 packets or IPv4 packets into IPv6 packets. The encapsulated IPv4 packets are transmitted through IPv4 routing system or IPv6 packets.
The advantages and disadvantages of tunnel technology are as follows:
Advantages:
- No information lost
- Network o&M is relatively simple
- Easy to implement, as long as the tunnel entrance and exit modifications
Disadvantages:
- The tunnel needs to be encapsulated and decapsulated, so the forwarding efficiency is low.
- IPv4 cannot communicate with IPv6
- Unable to resolve IPv4 shortage
- Poor NAT compatibility
NAT – PT technology
Network address converter with protocol converter attached to NAT-PT technology. It is a communication mode between pure IPv6 nodes and IPv4 nodes. All the translation work including address and protocol is completed by network devices. Both nat-PT and NAT-PT provide one-to-one mapping between IPv6 and IPv4 addresses. However, dynamic NAT-PT requires an IPv4 address pool for dynamic address translation. One of the biggest advantages of NAT-PT technology is that it does not need to upgrade IPv4 and IPv6 nodes, but the disadvantages are also very obvious. The disadvantage is that the implementation method for IPv4 nodes to access IPv6 nodes is complicated, and the processing cost of protocol translation and address translation on network devices is high. It is usually used when other communication modes are unavailable.
conclusion
Regardless of the technology, we need to consider the following aspects: periodicity, cost, technical difficulty, and ease of deployment. According to the current analysis of the transition technology, the double stack technology and tunnel technology are more convenient and easier to implement. As a leading data cloud service provider in China, Youbaiyun began to invest in the construction of IPv6 in 2016 to provide customers with intelligent IPv6 services, which can realize the gateway conversion from IPv4 to IPv6 without configuration modification. Customers and end users can enjoy IPv6’s more stable and faster network quality early.
Recommended reading:
Open the new era of IPv6, after the upgrade of IPv6 fierce?
IPv6, which provides an IP address for each grain of sand