Before introducing the IPv4 to IPv6 transition technology, let's take a brief look IPv4 and IPv6. What is IPv4? IPv4 called the Internet Protocol version 4, it is assigned a logical address for each network on the Internet and each host, IP address is a 32-bit binary number, in fact, doing only 2 ^ 32 addresses, these addresses there are divided into a, B, C, D, E 5 class, and only the more common class B and class C, these two types of address even more limited number counted in the rapid development of Internet and now, in 20112 May 3, the IANA IPv4 address pool has been fully depleted, which seriously hampered the development of the Internet. For IPv6, the next generation IP protocol is used instead of IPv4, IPv6 address length is 128, four times the length of IPv4 addresses, IPv6 addresses specifically how much of it? IPv6 128-bit address length can provide 3.402823669 × 10³⁸ addresses, small series of bad math, can not be calculated in the end how much to borrow a word to describe, IPv6 can assign an address to every grain of sand in the world. If this allocation is GirlFriend that nice ah, so engineers can build a more powerful technology, but also has a small series of GF.
IPv4 VS IPv6
In addition to abundant number of IP addresses, IPv6 compared to IPv4 there are many other advantages.
Faster transfer speeds
Fast, faster, very fast, which is now the Internet's long-term pursuit, while the IPv6 header is fixed, so carrying a bunch of tedious data Unlike IPv4, a short header enhance the network data forwarding efficiency. IPv6 routing tables and since the smaller, more capable of polymerization to ensure that the data forwarding path is shorter, greatly improves the transmission efficiency.
More secure transmission
Although more secure site is open SSL, but still there are a lot of sites does not use HTTPS. And not forced to use the IPv4 protocol IPSec data encryption, data leakage leading to the site transmitted in clear text, and IPv6 is the direct integration of IPSec, the network layer authentication and data encryption, to provide users with end to end data security to ensure that data is not hijacked .
More friendly for mobile end
Mobile phones and other mobile devices can now be said to have become an indispensable part of many people of, IPv6 protocol can enhance the mobile nature of mobile terminals, security features, routing features, while reducing the difficulty and investment in network deployment.
Plug and Play
Compared with the same IPv4, IPv6 adds automatic configuration and reconfiguration techniques for information such as IP address automatically update the configuration additions and deletions to enhance the IPv6 manageability.
IPv4 to IPv6 transition technologies
IPv6 was proposed in 1992, and now has more than twenty years, the development of IPv6 technology has been very mature, then the IPv4 to IPv6 switching can look at all of it, the answer is definitely no. IPv6 is not mainly due to improvement of IPv4, IPv6 is a new protocol, the link layer network protocol is different, can not communicate directly. And now almost all use IPv4, so this conversion is likely to continue for a long time.
Currently, IETF has set up a special working group to study the conversion of IPv4 to IPv6, and many proposals have been put forward, we first introduce several of.
Dual-stack technology
IPv4 and IPv6 have similar network layer protocol functions are based on the same hardware platform, run two protocol stacks IPv4 and IPv6 simultaneously from a single master with IPv4 / IPv6 dual stack node called dual stack node, the junction point both send and receive IPv4 packets, you can also send and receive IPv6 packets. They may be used interworking between IPv4 and IPv4 node, the IPv6 can be used directly communicate IPv6 node. IPv4 dual stack node contains the IPv6 network layer, but the transport layer protocol (such as TCP and UDP) use of a single still.
What are the specific advantages and disadvantages of dual-stack technology it?
advantage:
- High efficiency, no information is lost
- Good interoperability, network planning simple
- Give full play to all the advantages of IPv6 protocol, routing table smaller, higher security.
- Multi-resource consumption, operation and maintenance complex.
Disadvantages:
- Can not be achieved IPv6-IPv4 interworking
- High requirements on the network device, the internal network transformation involved is relatively large, compared to a longer periodicity.
Tunneling
Tunneling refers to the header of another protocol packet encapsulated directly in front of the original packet header, which can achieve transmission directly on networks with different protocols, this mechanism is used on the IPv4 network IPv6 site, a site may be a host, there can be multiple hosts. The tunneling of IPv6 packet encapsulated into an IPv4 packet, or the packet is encapsulated into an IPv4 packet in IPv6, IPv4 encapsulated packets will be transmitted via a transmission route system in the IPv4 or IPv6 packets.
Advantages and disadvantages of the tunnel technology was:
advantage:
- No information is lost
- Network operation and maintenance simple compared
- Easy to implement, make changes as long as the entrance and exit of the tunnel
Disadvantages:
- Decapsulating the encapsulated tunnel, forwarding efficiency is low.
- Can not be achieved IPv6-IPv4 interworking
- Can not solve the shortage of IPv4
- NAT compatibility is not good
NAT-PT technology
Network Address Translator NAT-PT technology comes protocol converter. Interworking system between a pure IPv6 nodes and IPv4 node, including all the addresses, the protocol, including the switching operation is completed by the network device. NAT-PT include both static and dynamic, both of which provide a one to one mapping of IPv6 addresses and IPv4 addresses, but dynamic NAT-PT needs an IPv4 address pool for dynamic address translation. NAT-PT technology have the biggest advantage is no need for upgrading IPv4, IPv6 nodes, but the disadvantage is also very obvious. The disadvantage is that implementation of the access node IPv6 IPv4 node is more complex, network protocol conversion device, the address conversion processing overhead is generally used in a large exchange of other ways unusable.
to sum up
Whatever the technology, we must consider the following aspects, periodic, cost, technical difficulty, ease of deployment. According to analysis of the current transition technology, dual-stack technology and tunneling technology is higher compared to the ease of use, and easier to implement. As the leading data cloud service vendors, they shoot the cloud began to invest in construction of IPv6 in 2016, providing customers with intelligent IPv6 services without the need for configuration changes, you can achieve the conversion from IPv4 to IPv6 gateway, customers and end users IPv6 can step back to enjoy more stable and fast network quality.
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