How many bits is the length of an ipv6 address?

The ipv6 address length is 128 bits, which is 4 times the length of the IPv4 address; ipv6 has 3 representation methods, namely: 1. Hexadecimal representation, format such as "ABCD:EF01:2345 :6789:ABCD:EF01:2345:6789"; 2. 0-bit compressed representation, format such as "0:0:0:0:0:0:0:0 → ::"; 3. Embedded IPv4 address representation Law.

The operating environment of this tutorial: Windows 7 system, Dell G3 computer.

How many bits is the length of an ipv6 address?

The IPv6 address length is 128 bits, which is four times the IPv4 address length. Therefore, the IPv4 dotted decimal format is no longer applicable, and hexadecimal representation is used. IPv6 has three representation methods.

1. Fractional hexadecimal notation

The format is X:X:X:X:X:X:X:X, where each X represents 16b in the address, Expressed in hexadecimal, for example:

ABCD:EF01:2345:6789:ABCD:EF01:2345:6789

In this representation, the leading 0 of each X can be omitted, for example:

2001:0DB8:0000:0023:0008:0800:200C:417A→ 2001:DB8:0:23:8:800:200C:417A

2. 0-bit compressed representation

In some cases, an IPv6 address may contain a long period of 0s, and the continuous period of 0s can be compressed into "::". However, in order to ensure the uniqueness of address resolution, "::" can only appear once in the address, for example:

FF01:0:0:0:0:0:0:1101 → FF01::1101
0:0:0:0:0:0:0:1 → ::1
0:0:0:0:0:0:0:0 → ::

3. Embedded IPv4 address representation

In order to achieve IPv4-IPv6 interoperability, The IPv4 address will be embedded in the IPv6 address. At this time, the address is often expressed as: Decimal representation, such as ::192.168.0.1 and ::FFFF:192.168.0.1 are two typical examples. Note that in the first 96b, the method of compressing 0 bits still applies.

IPv6 is the abbreviation of "Internet Protocol Version 6" in English. It is a protocol designed by the Internet Engineering Task Force (IETF) to replace IPv4. A first-generation IP protocol whose number of addresses claims to be able to assign an address to every grain of sand in the world.

The biggest problem of IPv4 is the insufficient network address resources, which seriously restricts the application and development of the Internet. The use of IPv6 can not only solve the problem of the number of network address resources, but also solve the obstacles for multiple access devices to connect to the Internet.

The Internet Assigned Numbers Authority (IANA) made recommendations to the International Internet Engineering Task Force (IETF) in 2016, requiring that the newly developed international Internet standards only support IPv6 and are no longer compatible with IPv4.

Advantages and features

Comparison of IPv4 and IPv6 addresses

Compared with IPV4, IPV6 has the following advantages:

一, IPv6 has a larger address space. IPv4 stipulates that the length of an IP address is 32, and the maximum number of addresses is 2^32; while the length of an IP address in IPv6 is 128, that is, the maximum number of addresses is 2^128. Compared with the 32-bit address space, its address space increases by 2^128-2^32.

2. IPv6 uses a smaller routing table. IPv6 address allocation follows the principle of aggregation from the beginning, which allows the router to use one record (Entry) in the routing table to represent a subnet, which greatly reduces the length of the routing table in the router and improves the forwarding efficiency of the router. Packet speed.

3. IPv6 adds enhanced multicast (Multicast) support and flow control (Flow Control), which gives multimedia applications on the network significant development opportunities and improves quality of service (QoS, Quality of Service). Service) control provides a good network platform.

4. IPv6 has added support for automatic configuration (Auto Configuration). This is an improvement and extension to the DHCP protocol, making the management of the network (especially the LAN) more convenient and faster.

5. IPv6 has higher security. In IPv6 networks, users can encrypt network layer data and verify IP messages. The encryption and authentication options in IPv6 provide packet confidentiality and integrity. Greatly enhances network security.

6. Allow expansion. IPv6 allows the protocol to be expanded if new technologies or applications require it.

7. Better header format. IPv6 uses a new header format with options separate from the base header, with options inserted between the base header and the upper layer data if needed. This simplifies and speeds up the routing process because most options do not need to be selected by the router.

8. New options. IPv6 has some new options to implement additional functionality.

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