Analysis of IPV6 and loopback address

IPV6 and loopback address are short for Internet Protocol Version 6. Internet Protocol is translated into Internet Protocol ". IPv6 is the next-generation IP protocol designed by IETF (Internet Engineering Task Force) to replace the current version of IP protocol (IPv4. Currently, the version of the IP protocol is 4 (IPv4 for short), and its next version is IPv6. IPV5 has been reserved for the Internet information flow protocol developed before IPv6. It has never been widely deployed and will not be publicly used. The IPV6 address is 128 characters in length, and the address space is increased by 96 to the power of 2, reaching 128 times of 2 (the maximum number of IPV4 addresses is 32 times of 2 ); www.2cto.com flexible IP packet header format. The optional fields with Variable Length in IPV4 are replaced by a series of Fixed-format extension headers. The option section in IPV6 also appears in a different way, so that the router can simply pass through the option without any processing, which speeds up message processing. IPV6 simplifies the packet header format and has only eight fields, it accelerates packet forwarding, increases throughput, and improves security. Identity Authentication and privacy are key features of IPV6. It supports more types of services, allows protocol evolution, and adds new features to adapt to future technology development. IPv6 editing address: the most significant change from IPv4 to IPv6 is the length of the network address. The IPv6 addresses defined in RFC 2373 and RFC 2374 are 128-bit long, as described in the following chapter. The expression of IPv6 addresses generally uses 32 hexadecimal numbers. In many cases, IPv6 addresses are composed of two logical parts: a 64-bit network prefix and a 64-bit host address. Generally, the host address is automatically generated based on the physical address, it is called a EUI-64 (or a 64-bit extended unique identifier ). IPv6 Address indicates that the colon hexadecimal IPv6 address is 128-bit long, but usually eight groups are written, each group is in the form of four hexadecimal numbers n: n: n ,. For example, FE80: 0000: 0000: 0000: AAAA: 0000: 00C2: 0002 is a valid IPv6 address. If the above address looks too long to be compressed, there is another way to reduce its length, called the zero compression method. If the values of several consecutive segments are all 0, these 0 values can be expressed simply as:. The above address can be written as FE80: AAAA: 0000: 00C2: 0002. It should be noted that only the 0 of consecutive segments can be simplified, and the 0 before and after them must be retained. For example, the last 0 of FE80 cannot be simplified. This can only be used once. In the above example, the 0000 next to AAAA cannot be simplified again. Of course, it can also be used after AAAA: In this case, the first 12 0 cannot be compressed. The purpose of this restriction is to accurately restore the compressed 0. otherwise, you cannot determine the number of zeros for each. at the same time, the leading zero can be omitted, so: 2001: 0DB8: 02de: 0e13 is equivalent to 2001: DB8: 2de: e13. 0: 0: 0: 0: 0: 0: 0: 0: 0: 0: 0: 0: 1. The unspecified address 0: 0: 0: 0: 0: 0: 0: 0: 0 is compressed in the form ::. This form combines IPv4 and IPv6 addresses. In this case, the address format is n: d. d. d. d. Each n represents the hexadecimal value of one of six IPv6 High-Order 16-bit address elements, and each d represents the IPv4 address in decimal format. An IPv6 address can be embedded into an IPv4 address and written as a mixture of IPv6 and IPv4. IPv6 can be embedded with IPv4 addresses. The IPv4 image address is in the following format: ffff: 192.168.89.9. The address is still an IPv6 address, only 0000: 0000: 0000: 0000: 0000: ffff: c0a8: another way of writing 5909. IPv4 compatible addresses are written as follows: 192.168.89.9 is an IPv4 image address, which is still an IPv6 address, but only 0000: 0000: 0000: 0000: 0000: 0000: c0a8: another way of writing 5909. IPv4 compatible addresses have been discarded, so the address format may not be supported by devices and programs in the future. The leading position in an IPV6 address defines the specific IPv6 address type. A variable-length field containing the leading bits is called a format prefix (FP ). The IPv6 unicast address is divided into two parts. The first part contains the address prefix, and the second part contains the interface identifier. The following describes the simple combination of IPv6 addresses and prefixes: ipv6 address/prefix length. The following is an example of an address with a 64-bit prefix. 3FFE: FFFF: 0: CD30: 0: 0: 0: 0/64. The prefix in this example is 3FFE: FFFF: 0: CD30. This address can also be written in compressed form, such as 3FFE: FFFF: 0: CD30:/64. Www.2cto.com Unicast address (Unicast) is used as the identifier of a single interface. The packet sent to this address is passed to the identified interface. The Unicast address and multi-channel broadcast address are distinguished by the high-order eight-byte value. The high-sequence eight-byte of a multi-channel broadcast address has a hexadecimal value FF. Any other value of this eight-byte identifies the unicast address.
Anycast is also called Pan-play. The identifier of a group of interfaces (usually different nodes ). The packets sent to this address are passed to all interfaces identified by this address (the nearest route is used based on the route ). The anycast address type replaces the IPv4 broadcast address. The Multicast function in Multicast address (Multicast) IPv6 is similar to that in IPv4: as a group of interfaces, Multicast is very interested in the traffic. Unicast: An identifier for a single interface. A packet sent to a unicast address is delivered to the interface identified by that address. anycast: An identifier for a set of interfaces (typically belonging to different nodes ). A packet sent to an anycast address is delivered to one of the interfaces identified by that address (the "nearest" one, according to the routing protocols 'measure of dis Tance ). multicast: An identifier for a set of interfaces (typically belonging to different nodes ). A packet sent to a multicast address is delivered to all interfaces identified by that address. the loopback address (www.2cto.com) is a special address used by the host to send communications to itself. The loopback address provides a shortcut for communication between TCP/IP applications and services running on the same device. If the two services on the same host use the loopback address instead of the assigned host address, the lower layer of the TCP/IP protocol stack can be bypassed. Ping the loopback address to test the TCP/IP configuration on the local host. The IPv4 loopback address is one of the reserved addresses 127.0.0.1. Although only 127.0.0.1 is used, 127.0.0.0 to 127.255.255.255 are retained. Any address in this address block will ring back to the local host. Any address in this block will never appear in any network. Like IPv4, IPv6 also provides a special loopback address for testing. The datagram sent to this address is loopback to the sending device. However, IPv6 uses only one address for this function, rather than one address block. The return address is 0: 0: 0: 0: 0: 0: 0: 1. It is generally expressed as ": 1" in the form of zero compression ". Author: desert3