What are the three representation formats for IPV6 addresses? And give examples?
There are three conventional formats that can be used to represent IPv6 addresses as text strings: the first is x:x:x:x:x:x:x:x:x, where “x” is a hexadecimal value that corresponds to each of the eight 16-bit segments of a 128-bit address. For example: 2001:fecd:ba23:cd1f:dcb1:1010:9234:4088 Some IPv6 addresses may contain a long string of zero bits. To facilitate textual description of such addresses, a special syntax has been developed. The use of “:::” indicates that there are multiple sets of 16 bits of zeros. “:::” can only occur once in an address and can be used to compress leading, trailing, or adjacent 16-bit zeros in an address. For example: fec0:1:0:0:0:0:0:0:1234 can be represented as fec0:1::1234 When dealing with mixed environments with IPv4 and IPv6 nodes, another form of IPv6 address can be used. That is, x:x:x:x:x:x:d.d.d.d, where “x” is the hexadecimal value of the 96-bit high-order byte of the IPv6 address, and “d” is the decimal value of the 32-bit low-order byte. In general, “IPv6 address mapped to IPv4” and “IPv4-compatible IPv6 address” can be expressed in this representation. These two types of addresses are discussed in later sections. For example: 0:0:0:0:0:0:0:10.1.2.3 and ::10.11.3.123.
How many bytes are used to represent the new IPV6 addresses?
IPv6 addresses are 128 bytes long.
IPv6, which stands for “Internet Protocol Version 6,” is the next-generation IP protocol designed by the Internet Engineering Task Force (IETF) to replace IPv4, with a claimed number of addresses that can be programmed into every grain of sand in the world. sand is programmed with an address.
Because the biggest problem with IPv4 is its limited network address resources, which severely restricts the application and development of the Internet. the use of IPv6 not only solves the problem of the number of network address resources, but also resolves the obstacles to connecting multiple access devices to the Internet.
IPv6 has 3 representations:
1. Columnar Hexadecimal Representation
Format X:X:X:X:X:X:X:X:X:X, where each X denotes 16b in the address in hexadecimal
For example: ABCD:EF01:2345. 6789:ABCD:EF01:2345:6789
2. 0-bit compressed representation
In some cases, the middle of an IPv6 address may contain a very long section of zeros, and a consecutive section of zeros can be compressed into “::”. However, to ensure uniqueness in address resolution, “::” can only appear once in an address.
For example: FF01:0:0:0:0:0:0:0:1101→FF01::1101
3. Embedded IPv4 address representation
In order to realize the IPv4-IPv6 interoperability, the IPv4 address is embedded in the IPv6 address, and at this time, the address is often expressed as follows: X:X:X:X:X:X:X:X:X:X:X:X:X:X:X:X:D.D.D.D. The first 96b uses the colon sixteen. The first 96b are expressed in colon-dotted hexadecimal, while the last 32b addresses are expressed in IPv4 dotted decimal.
A brief description of the IPv6 address representation and its compression
What is IPv6?The existing Internet operates on the basis of the IPv4 protocol.IPv6 is the next version of the Internet protocol, which was initially proposed because, with the rapid growth of the Internet, the limited address space defined by IPv4 will be exhausted, and the lack of address space will surely affect the further development of the Internet. . In order to expand the address space, it is proposed to redefine the address space through IPv6. IPv4 adopts 32-bit address length and has only about 4.3 billion addresses, which are estimated to be allocated between 2005 and 2010, whereas IPv6 adopts 128-bit address length, which can provide almost unlimited addresses. A conservative approach to estimating the actual addresses that can be allocated by IPv6 would be more than 1,000 addresses per square meter of area on the entire planet. In addition to solving the address shortage problem once and for all, other problems that were not well solved in IPv4 were also taken into account in the design process of IPv6. The main advantages of IPv6 are reflected in the following aspects: expanding the address space, increasing the overall throughput of the network, improving the Quality of Service (QoS), better guarantee of security, support for Plug and Play and mobility, and better implementation of multicast functionality. It is clear that the advantages of IPv6 can contribute directly or indirectly to the above challenges. The most prominent of these is that IPv6 greatly expands the address space and restores the end-to-end connectivity lost due to address constraints, providing the basic conditions for the popularization and deepening development of the Internet. Of course, IPv6 is not perfect, once and for all, and cannot solve all the problems. ipv6 can only be continuously improved in the development, and cannot happen overnight, the transition needs time and cost, but in the long run, ipv6 is conducive to the sustainable and long-lasting development of the Internet. ipv6 address format ipv6 address size of 128 bits. The preferred IPv6 address representation is: xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx, where each x represents a 4-bit hexadecimal number.IPv6 addresses range from 0000:0000:0000:0000:0000:0000:0000 to ffff. ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff. IPv4 addresses are composed of 32-bit binary codes. The format is xxx.xxx.xxx.xxx, where the x represents a three-bit binary number. In addition to this preferred format, IPv6 addresses can be specified in two other short formats: by omitting leading zeros
IPv6 addresses are specified by omitting leading zeros. For example, IPv6 address 1050:0000:0000:0000:0005:0600:300c:326b can be written as 1050:0:0:0:5:600:300c:326b. double colon
Specify an IPv6 address by using a double colon (:::) instead of a series of zeros. For example, the IPv6 address ff06:0:0:0:0:0:0:0:c3 can be written as ff06::c3. a double colon can be used only once in an IP address. another optional format for IPv6 addresses combines a colon with a dotted representation so that an IPv4 address can be embedded in an IPv6 address. Specify a hexadecimal value for the leftmost 96 bits and a decimal value for the rightmost 32 bits to indicate the embedded IPv4 address. This format ensures compatibility between IPv6 nodes and IPv4 nodes when working in a mixed network environment. These two types of IPv6 addresses use this optional format: IPv6 address mapped through IPv4
This type of address is used to represent an IPv4 node as an IPv6 address. It allows IPv6 applications to communicate directly with IPv4 applications. For example, 0:0:0:0:0:0:ffff:18.104.22.168 and ::ffff:22.214.171.124/96 (short format). IPv4-compatible IPv6 address
This type of address is used for tunneling. It allows IPv6 nodes to communicate over an IPv4 infrastructure. For example, 0:0:0:0:0:0:0:126.96.36.199 and ::188.8.131.52/96 (short format).