Automatic IPv6 Stateless Address Configuration

IPv6 Stateless Address automatic configuration IPv6 stateless automatic configuration on the host side does not require configuration, on the vro side requires a small amount of configuration, and does not require other servers. The stateless mechanism allows the host to use its own known information and router announcement information to generate its own address. A vro advertises a network prefix to define a subnet. The host generates an interface identifier to indicate an interface in the subnet. An IPv6 address consists of these two parts. Without the involvement of a vro, the host can generate only one local link address, which can be used for local network communication. In the automatic configuration mode, the host obtains the interface address, configuration information, and parameters through the server. The server maintains a host and a database with the configured address. The stateful automatic configuration allows the host to obtain the address and other configuration information from the server. Stateful automatic configuration and stateless automatic configuration can be complementary, for example, the host can obtain the address through stateless automatic configuration and other information (such as the gateway and DNS server address) through stateful automatic configuration ). The use of stateless and stateful address configuration depends on the network design. The administrator can use stateful Address Configuration when strictly managing the addresses. Otherwise, stateless addresses are sufficient. The two configuration mechanisms can be used at the same time. The administrator can modify the relevant domain in RA (router announcement) to determine which automatic configuration mechanism to use. Stateless Address automatic configuration can only be used for the host, not for the router. The automatic configuration of the host depends on the information sent from the server. The router must use other configuration mechanisms. To ensure that duplicate addresses are not displayed on a specific link, the node performs "duplicate address detection" before applying an address to an interface, whether it is stateful or stateless, and automatically configured, detection is required. Stateless automatic configuration, with the following goals: 1. when a new device is connected to the network, no manual configuration is required. in a small network, no dedicated server or router is required for address allocation. A large site with multiple networks should not require a stateful address to configure the server 4. recompile the hosts of a site. 5. the system administrator can determine the configuration method used (stateful, stateless, or both). Before the local link address is configured to the interface, the node must confirm the "probe" address, no other nodes are used. Therefore, it sends an NS heat preservation and carries the detection address. If you receive the NA message from the needle to the NS, it indicates that the detection address is occupied and the automatic configuration will terminate. To avoid this problem, the administrator can provide an alternative interface identifier to replace the original interface identifier so that automatic configuration can continue. Otherwise, you need to manually configure the local link address and other addresses of the interface. When a successful probe address is unique, the IP address is successfully configured to the interface, and the interface has the IP communication capability. After configuring the local link address, you need to confirm whether you can receive the RA notice or detect that no vro exists. If a vro exists in the local network, the vro notification message is sent to instruct the host to use the configuration method. If no vro exists in the local network, use stateful automatic configuration. Although the router periodically issues RA, to speed up automatic configuration, after the local link address takes effect, the host sends one or more router request packets to the multicast address of all routers. After receiving these packets, the router responds to the RA packet. The RA message may contain information used to automatically generate the local site address and global unicast address for stateless configuration, such as the address prefix and other router cycle issues RA, the host continuously receives new notification messages. The host processes each notification message to change and refresh the configuration status. All addresses must be checked for uniqueness before being assigned to an interface. In the case of Stateless Address configuration, the uniqueness of an address is mainly guaranteed by an interface identifier, if the local link address of the interface is unique, duplicate address detection is not required for other addresses generated using the same identifier.