Protocol forest 04 address depletion crisis (IPv4 and IPv6 addresses)

Author: vamei Source: http://www.cnblogs.com/vamei welcome reprint, please also keep this statement. Thank you!

Thanks, xwpcom for error correction.

 

IP address is an important part of the IP protocol. It can identify any device connected to the Internet. In the IP address relay, we can see that the IP address of the IP packet is written in the header of the outbound IP address and the destination IP address. The IP address carried on the IP package works with the router to allow the IP packet to be transmitted from one computer on the Internet to another.

In IP address relay, we use IPv4 as an example to describe the IP packet format. IPv4 and IPv6 are two successive IP protocol versions. The IPv4 address is32-bit0/1 sequence, such as 11000000 00000000 0000000 00000011. To facilitate human recording and reading, we usually divide 32-bit 0/1 into 4-Segment 8-bit sequences and use themDecimalTo represent each segment (in this way, the range of a segment is 0 to 255 )..Separated. For example, the above address can be expressed as 192.0.0.3. The IPv6 address is a 128-bit 0/1 sequence. It is also divided by 8 bits, and each segment is recorded in hexadecimal notation (hexadecimal instead of hexadecimal notation, this can shorten the written IPv6 address ).:Separated.

 

IP Address Allocation

IP Address allocation is a policy issue.ICANN(The Internet Corporation for Assigned Names and Numbers) is the central management organization of the Internet. The IANA (Internet Assigned Numbers authourity) Department of ICANN is responsible for allocating IP addresses to five regional Internet registrars (RIR, Reginal Internet registries), such as APNIC, which is responsible for IP Address Allocation in the Asia Pacific region. Then RIR further allocates the address to the localISP(Internet Service Provider), such as China Telecom and China Netcom. The ISP then assigns the IP addressInstitutionYou can also allocate a Class A address to a super-large organization and a class C address to an Internet cafe. The Organization can further allocate IP addresses to various hosts within the LAN. (For A/B/C Class addresses, refer to IP relays)

Five Regions in charge of RIR

 

Not all addresses are allocated. Some addresses are reserved for broadcast, test, and private network usage. These addresses are calledPrivate address(Special-use address ). You can query rf120035 to find out which addresses are private addresses.

(RFC, Request for comments. RFC is a series of technical documents used to record Internet-related technical and Protocol requirements. Each RFC file has a fixed number. They are an important property of the Internet. You can find the RFC file by http://www.rfc-editor.org)

 

IPv4 address depletion

Because the IPv4 address is32-bitSo it can provide 232, that is, about4 billionAddresses. If each person on earth has an IP address, the IPv4 address is far from enough. What's more, the number of inbound devices held by each user may be much more than one, which shows the IP address requirements of a household. This demand is already quite common:

We need more IP address!

The IPv4 address depletion Date of RIR on each continent is displayed (IANA has allocated all IP addresses to each RIR ):

Estimated depletion date for five RIR regions

 

Although some technical measures (suchNAT technology, I willArticleIn-depth Nat)This slows down the urgency of the situation, but the IPv4 addressDepletionThe day will soon come. Obviously, we need more IP addresses to meet the needs of the explosive growth of internet devices.

Too much stuff for IPv4

 

Longer = better

The most important improvement of IPv6 addresses is:Lengthen. The IPv6 address is128 bits. To be precise, IPv4 has 4,294,967,296 addresses, while IPv6 has

340,282,366,920,938,463,374,607,431,768,211,456

Addresses. What is this concept? We can roughly calculate

The earth surface area is approximately510,067,866,000,000 m². Within an area of 1 cm² square meters (approximately the size of the top), we can have6.67x1016IP addresses! So in the short term, we should not see the embarrassment of IPv6 exhaustion. (It is not ruled out that in the future, the computer will appear in the molecular size, so we will have the IPv6 depletion crisis)

Therefore, in order to solve the IPv4 address depletion crisis, this is the conclusion:

 

Summary

IPv4 addresses are exhausted, while IPv6 provides more IP addresses through a longer sequence. Migration from IPv4 to IPv6 is ongoing.

The main obstacle to migration is the incompatibility between IPv4 and IPv6 formats. The old routers support IP packets in IPv4 format, but they cannot understand the IP packets in IPv6 format. Therefore, this migration process must be followed by device updates. However, many of our Internet assets are built on an IPv4 network. It is impossible to stop IPv4 network services overnight and migrate them to an IPv6 network as a whole. This migration process is doomed to be bumpy.

 

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