DHCPv6 Stateful Client

The Dynamic Host Configuration Protocol for IPv6 (DHCPv6) stateful client allows an ICX device to obtain an IPv6 address and other configuration parameters, such as domain name server (DNS) and domain search list, from a DHCPv6 server.

Overview

The DHCPv6 stateful client method is used when the network administrator requires more control over the IPv6 address assignment and other network configurations are needed. The DHCPv6 stateful client is essential for environments where precise IPv6 management and configuration are required.

Therefore, when the DHCPv6 stateful client is configured, the client relies on the DHCPv6 server for its IP address and configuration. The process involves a series of messages, such as Solicit, Advertise, Request, and Reply. The DHCPv6 message exchange process involves a series of messages between the DHCPv6 client and server to configure network settings. The key messages in this process are:

  • Solicit: The DHCPv6 client sends a Solicit message to locate available DHCPv6 servers.
  • Advertise: Upon receiving the Solicit message, DHCPv6 servers respond with an Advertise message informing the DHCPv6 client that the DHCPv6 server is available and willing to provide configuration parameters.
  • Request: The DHCPv6 client then sends a Request message to the server, asking for specific configuration parameters, including an IPv6 address, DNS information, and other configuration details.
  • Reply: The server responds with a Reply message, providing the requested configuration parameters, such as the IPv6 address, DNS server addresses, and other network settings.
  • Renew: When the address’s preferred lifetime is halfway through, the client sends a Renew message to the server to request an extension of the address lifetime.
  • Rebind: If the client does not receive a response to the Renew message after 80% of the valid lifetime has passed, it sends a Rebind message to any available DHCPv6 server to extend the lifetimes of the assigned IPv6 addresses and update other configuration parameters.
  • Release: When the client no longer needs one or more of the assigned IPv6 addresses, it sends a Release message to the server to inform it that the addresses will no longer be used.
Note: The peer router must send Router Advertisement (RA) messages with the Managed (M) flag set to 1, indicating that stateful DHCPv6 is required.

Requirements

This feature has the following hardware or software requirements for feature enablement or usage:

  • DHCPv6 Client is not supported for RUCKUS ICX 7150 devices.
  • A DHCPv6 server must be available on the network to provide IPv6 addresses and configuration parameters.
  • A peer router, which is another router on the same network segment, must be available on the network.

Considerations

This feature has the following considerations pertaining to feature enablement or usage:

  • The DHCPv6 stateful client obtains a global unicast IPv6 address from the DHCPv6 server.
  • The peer router must be configured to support stateful DHCPv6. For more information, refer to Configuring a Peer Device for DHCPv6 Address Auto-configuration.
  • In addition to the IPv6 address, the DHCPv6 client can receive other configuration parameters such as DNS server addresses, domain search lists, and boot file URLs.
  • The DHCPv6 client must manage the lease times for the assigned IPv6 address, including renewing and rebinding as necessary.
  • The default gateway and prefix length are always obtained via RA messages.
  • Stacking ports, tunnel ports, and loopback ports are not supported.
  • After a stack switchover, the dynamic IP is relearned. Upon reboot or switchover, the DHCPv6 client's lease time is determined by the DHCPv6 server's response. If the server provides the remaining lease time, the client adopts this as its valid lifetime.

Best Practices

Verify that the DHCPv6 client and server are compatible and correctly configured to communicate.

Prerequisites

This feature has the following prerequisites to feature enablement or usage:

  • The peer router must be configured to send Router Advertisement (RA) messages with the Managed Configuration Flag (M-flag) set to 1, using the ipv6 nd managed-config-flag command. Refer to the RUCKUS FastIron Command Reference for more information.
  • The peer router must be configured to advertise the specified prefix as being assigned to the local link using the ipv6 nd prefix-advertisement command. This ensures that nodes sending traffic to addresses within this prefix will consider the destination to be reachable on the local link.
  • IPv6 must be enabled on the ICX device interface. Refer to the ipv6 enable command in the RUCKUS FastIron Command Reference for more information.
Parent topic: DHCPv6 Client