Brief Introduction to IPv6 Network Protocol address features

The emergence and use of the new standard IPv6 network protocol has passed for many years. So the factors that make IPv6 network protocol more commercialized are its special address structure. Now let's take a look at this content. First, let's take a look at the conversion of the two Protocols.

1. IPv4 to IPv6 network protocol conversion

The increasing demand for IP addresses is a catalyst for IPv6 development. It is estimated that more than 1 billion mobile phones, PDAs, and other wireless devices need to access the Internet only in the wireless field, in addition, each device requires a unique IP address. In addition, billions of new homes need to get services over the Internet, such as TVs, refrigerators, and electric meters, connect through various technologies. Therefore, IPv4 to IPv6 needs to change the following aspects in a centralized manner:

(1) Expand the address capacity. Increase the IP address from 32 bits of IPv4 to 128 bits to support more address levels, A larger number of nodes are automatically configured in a simpler form of addresses ｡

(2) Change the Header Format. delete or become optional fields of IPv4 to reduce the overhead of packet processing and the bandwidth occupied by IPv6 headers ｡

(3) support expansion and option improvement. Modify the encoding method of the IP header option to improve the transmission efficiency and have fewer restrictions on the option length, this makes it more adaptable when new options are introduced ｡

(4) added the data stream label capability. After this new feature is added, the sender can request special processing, which is a packet with special transmission "stream, for example, a package of non-default quality service or "real-time" service can be labeled "｡

(5) Enhance the authentication and confidentiality functions, and support certification, data integrity, and? Optional? Extensions of snow data confidentiality can be described in IPv6 ｡

2. structure and content of IPv6 network protocol

Extended address

IPv6 uses a 128-bit IP address, which completely solves the problem of IPv4 address insufficiency? Eye 3? A 128-bit address space is enough for a large enterprise to connect all devices, such as computers, printers, and even pagers, to the Internet, the IPv6 address format is different from that of IPv4. an IPv6 IP address consists of eight address segments, each of which contains 16 address bits, it is written in 4 hexadecimal numbers and separated by colons. Besides the address space of 128 bits, IPv6 also designs an address with a hierarchical structure for point-to-point communication, called the Aggregately glob-al unicast address )｡

The first three addresses are the prefix of the address type, which is used to distinguish other address types, followed by the 13-bit tla id and 32-bit nla id, the 16-bit sla id and 64-bit host interface ID are used to identify the Top-Level Aggregator in the hierarchical structure and the lower-Level aggregation (NLA: next Level Aggregator), location Level aggregation (SLA: Site Level Aggregator), and host interface. TLA is a public network access point that is connected to long-distance service providers and telephone companies, obtain the address from an international Internet Registrar, such as IANA. NLA is usually a large ISP and applies for the address from TLA, and assign an address to the SLA. The SLA can also be called a Subscriber. It can be an organization or a small ISP. The SLA is responsible for allocating an address to its subscribers, generally, address blocks composed of consecutive addresses are allocated so that these organizations can establish their own address classification structure and identify different subnets. The bottom level of the hierarchical structure is the network host ｡

Stream

A stream is a group sequence sent from a specific node to a specific target node. The flag field of a data stream is used to mark any transmitted data stream, so that all words in the network can be energy-saving to identify the data and make special processing. The long data stream mark in IPv6 makes the length of the data packet exceeds the IPv4 data packet, its length is 64 kbyte. The maximum transmission unit (MTU) can be used to enable applications to obtain higher and more reliable data transmission ｡