Overview of DHCPv6

Definition

Dynamic Host Configuration Protocol for IPv6 (DHCPv6) is designed to assign IPv6 addresses, prefixes, and other network configuration parameters to hosts.

Purpose

The IPv6 protocol provides huge address space formed by 128-bit IPv6 addresses that require proper and efficient assignment and management policies. IPv6 stateless address autoconfiguration is widely used. Hosts configured with the stateless address autoconfiguration function automatically configure IPv6 addresses based on prefixes carried in Route Advertisement (RA) packets sent from a neighboring device.

When stateless address autoconfiguration is used, devices do not record IPv6 addresses of hosts. Therefore, stateless address autoconfiguration has poor manageability. In addition, hosts configured with stateless address autoconfiguration cannot obtain other configuration parameters such as the DNS server address. Internet service providers (ISPs) do not provide instructions for automatic allocation of IPv6 prefixes for devices. Therefore, users need to manually configure IPv6 addresses for devices during IPv6 network deployment.

DHCPv6 solves this problem. DHCPv6 is a stateful protocol for configuring IPv6 addresses automatically.

Compared with manual address configuration and IPv6 stateless address autoconfiguration that uses network prefixes in RA packets, DHCPv6 has the following advantages:

• Controls IPv6 address assignment better. A DHCPv6 device can record addresses assigned to hosts and assign requested addresses. This function facilitates network management.
• Assigns IPv6 address prefixes to network devices. This function facilitates automatic configuration and hierarchical network management.
• Provides other network configuration parameters such as the DNS server address.