Should IPv6 be stateful or stateless?
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What is IPv6 Autoconfiguration? IPv6 addresses are significantly uglier than IPv4 addresses, so one of the goals of the IPv6 standards is to reduce the number of times network managers and end users enter these addresses. In addition, the highly successful results which have come from deployments in enterprise networks using DHCP and PPP have proven the value of dynamic assignment of IP addresses. Two Types of Automatic Configuration Stateful Autoconfiguration The two types of autoconfiguration are "stateless" and "stateful." Stateful autoconfiguration is the IPv6 equivalent of DHCP. A new protocol, called DHCPv6 (and based closely on DHCP), is used to pass out addressing and service information in the same way that DHCP is used in IPv4. This is called "stateful" because the DHCP server and the client must both maintain state information to keep addresses from conflicting, to handle leases, and to renew addresses over time. Our network does not use DHCPv6. The DHCPv6 protocol is not yet standardized, although there are several drafts available, including "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)" (by J. Bound and C. Perkins) "Extensions for DHCPv6" (by C. Perkins) which are expected to move to proposed standard status shortly. Stateless Autoconfiguration The other type of autoconfiguration in IPv6 is Stateless Autoconfiguration. With Stateless Autoconfiguration, a host gains an address via an interface automatically "leasing" an address and does not require the establishment of an server to delve out address space. Stateless autoconfiguration allows a host to propose an address which will probably be unique (based on the network prefix and its Ethernet MAC address) and propose its use on the network. Because no server has to approve the use of the address, or pass it out, stateless autoconfiguration is simpler. This is the default mode of operation for most IPv6 systems, including servers. You can see how our Windows 2000 system has handled its IPv6 configuration by opening up a Command window. The command IPV6 IF will show you the interfaces for IPv6. Of these, interface 4 is the local area network connection. Notice that it has "autoconfigured" its address, and the low order 48 bits of the address look surprisingly like a MAC address. If you give the IPV6 RT command, you can see that our Windows 2000 system has also automatically discovered its router address.To see how simple it is to configure IPv6, go to the "Start->Settings->Network&Dial-Up Connections->Local Area Connection" menu and click "Properties." Notice when you select IPv6 that there are no properties---there is nothing to set up! Stateless autoconfiguration is described in RFC2462 ("IPv6 Stateless Address Autoconfiguration") with some proposed extensions in the Internet draft "Privacy Extensions for Stateless Address Autoconfiguration in IPv6." One of the advantages of DHCP is that it does more than handle IP address allocation. For example, DHCP can be used to let end systems discover their DNS servers. Thus, large networks will likely use a combination of stateless autoconfiguration to discover their address, and DHCPv6 servers to pass out other information, such as DNS servers, with a third mechanism for the system to register its name in the DNS. Similar to this post
Why is it beneficial to use stateless DHCPv6?Stateless DHCPv6 is used by nodes to obtain other information, such as a DNS server list and a domain name, that does not require the maintenance of any dynamic state for individual nodes.
What is IPv6 stateful?A stateful DHCPv6 server provides IPv6 addresses and "other information" to hosts. It also keeps track of the state of each assignment. It tracks the address pool availability and resolves duplicated address conflicts. It also logs every assignment and keeps track of the expiration times.
What is IPv6 stateless address?Stateless address autoconfiguration is the process that IPv6 nodes (hosts or routers) use to automatically configure IPv6 addresses for interfaces.
Is the IPv6 node has only stateful auto configuration?IPv6 supports the following types of auto-configuration: Stateful auto-configuration: This type of configuration requires a certain level of human intervention because it needs a Dynamic Host Configuration Protocol for IPv6 (DHCPv6) server for the installation and administration of the nodes.
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