DHCPv6 vs. Autoconfiguration - Two Winners …
There is some discussion, and perhaps confusion, about the role DHCPv6 and autoconfiguration play for IPv6 networks. I’d like to take a second to provide a quick level-set.
In IPv4 networks, there are two ways to assign addresses – static and DHCPv4. In IPv6, there are three ways – static, DHCPv6, and autoconfiguration. Just like for IPv4, some deployments lend themselves to one host provisioning mechanism and some another. IPv6 simply offers network designers more choices, where autoconfiguration is a valuable addition to the set. Autoconfiguration is not better or worse than DHCPv6 – just used in different use cases. (Note - DHCPv6 server and client support has been lacking in most platforms until recently – Windows 2008 Server and Vista have/will have good support)
For example, the classic deployment model for large enterprises, with sophisticated end-user workstations (read “Windows”) has pretty much always been DHCP for users and static addressing for servers. For IPv6, I would expect this model to hold – at least for the near future. DHCPv4 is well-understood by enterprise IT staff, and DHCPv6 is very similar operationally. Even if we skip a feature-by-feature comparison of the protocols, just given human nature and the fact that a lot of IT policies reflect the use of DHCP to manage address assignments, DHCPv6 is likely to be popular in the enterprise. That makes sense to me.
By contrast, the address provisioning model for lightweight, client-only devices like sensors or tracking devices (low power, low memory, low CPU capability, cheap) is likely to be stateless autoconfiguration. DHCP is a pretty sophisticated protocol to ask of a low-end device – like a temperature sensor dropped by the hundreds from a plane onto a volcanic hillside threatening a remote village. Using autoconfiguration the sensor would join the just-deployed RF network, autoconfigure an address and set a default route, and start reporting.
And these are just a couple of today’s big deployment models. IPv6 will be the IP protocol of choice for 30 years or so (starting now), and there will be lots of new devices and new deployment models invented ahead. DHCPv6 is a fine provisioning protocol, likely to be popular in the enterprise. Autoconfiguration will be the right tool for a lot of other types of deployments. Both will be valuable to this and the next generation of network builders.
