IPv6 makes network address segmentation more humane

In the traditional IPv4 Address Allocation, we mainly use three types of attacks. Then, we will explain it later. The Address Allocation for IPv6 is more user-friendly. It mainly divides network users into three types and allocates addresses for different user types. Let's take a look at the specific content. The first is the address allocation rules of the current version V4.

IP Address Allocation

IPv4 address allocation is based on categories in the initial stage. There are three main methods: A, B, and C, and two special network addresses D and E ｡

◆ Type A address: the first 7 bits are used for network identification, and the last 24 bits are used for host identification. Class A addresses can accommodate 128 networks, and any class A network can include 16777216 hosts ｡

◆ Type B address: the first 14bit is used for network identification, and the last 16bit is used for host identification. The class B address can accommodate 16384 networks, and any class B network can include 16384 hosts ｡

◆ Type C address: the first 21bit is used for network identification, and the last 8bit is used for host identification. The class C address can accommodate 2097152 networks, and any class C network can include 256 hosts ｡

Class A, B, and C addresses are interfaces used to identify A network node. They are called unicast addresses. Class D addresses are not used to identify A single interface, instead, it is used to identify a set of network node interfaces. Class E addresses are reserved addresses ｡

Class A network address is used to identify the largest network in the world, except for A small number of reserved and allocable addresses, class A addresses have been allocated. Class B addresses will also be used up ｡

IPv4 limits the actual addresses that can be used based on the management method described above. For example, a network with 300 users is expected to use a Class B address, however, if a Class B address is actually allocated, the user has 65536 address domains, which far exceeds the address space required by the user, resulting in a large waste of addresses ｡

To address the weakness of this address allocation method, IETF uses the ClassInter-DomainRoutin (CIDR, ClassInter-DomainRoutin) solution, you can set the boundary between the network number and the address number, that is, you can redefine the address mask according to the network size, in this way, multiple Class C addresses can be aggregated for users. However, the disadvantage of the CIDR solution is that the network number and host number in the address must be determined after the network mask is known ｡

The IPv6 protocol can allocate layer-based addresses based on users' needs, which is different from IPv4's block address allocation, in the latter mode, some addresses cannot be used. In the hierarchical Address allocation mode of IPv6, the advanced network management department can divide the Address Allocation area for the lower-level network management department, the lower-level network management department can further divide the lower-level management department into Address Allocation areas ｡

IPv6 divides users into three types ｡

(1) Use the internal network and Internet of the enterprise;

(2) the enterprise's internal network is currently used and the Internet may be used in the future:

(3) connect to the Internet through telephone lines at home, airport, hotel and other places ｡

IPv6 provides different address allocation methods for these users ｡

(1) four types of point-to-point communication/unicast addresses are used to identify the interface of a single network device. The Multicast Communication Group can be transferred to the interface of the address ID ｡

(2) Improved multicast address format: used to identify the set of device interfaces belonging to different nodes. multicast communication transmission groups can be sent to all interfaces of address IDs, this address method is very useful. For example, new messages sent from the network can be sent to all registered users. Special multicast addresses can be restricted to communication in a specific network link or in a specific system group. No broadcast is defined for IPv6 protocol. address, however, you can use multicast addresses instead ｡

(3) The new Anycast address format. The IPv6 Protocol introduces an arbitrary stream address to identify the device interface set of different nodes, any multicast group can be sent to an interface of the address ID. The interface for receiving information is usually the nearest network node. This method can improve the routing efficiency, A network node can use an address to indicate the number of intermediate hops that can pass through the transmission route in the communication process. That is, the information transmission route does not need to be determined by the router ｡