(Optional) Adjusting Global DHCPv6 Parameters

Configure transparent transmission of DHCPv6 packets, unicast communication, and two-message exchange between a DHCPv6 client and a DHCPv6 server based on actual network conditions.

Context

Transparent transmission of DHCPv6 packets and the speed threshold at which solicit packets are sent

When receiving a DHCPv6 Solicit packet from an online user terminal, the NetEngine 8000 F forces the user to go offline and waits until the user sends a DHCPv6 Solicit packet to obtain the address through DHCPv6.

If a user terminal that does not support retransmission of DHCP Solicit packets is restarted immediately after a user logout, the NetEngine 8000 F is unable to detect the logout event. In this case, run the dhcpv6 through-packet command to enable transparent transmission of DHCPv6 packets so that the user can normally log in to the NetEngine 8000 F.

The dhcpv6 solicit-speed-threshold command is used when the speed at which users go online needs to be limited.
Unicast communication and two-message exchange between a DHCPv6 client and a DHCPv6 server

The dhcpv6 unicast-option command must be run if the DHCPv6 server needs to communicate with DHCPv6 clients in unicast mode.

In certain situations, for example, when a DHCPv6 client retains the last IP address it was allocated, the client can obtain an IP address through a rapid two-message exchange if the Solicit packet sent from the client contains the Rapid Commit option and the server also supports this option.
Enable a CPE to detect a user logout immediately after the user goes offline from the BRAS.

In some abnormal scenarios, users are offline from the BRAS but are still online on the CPE. For example, the BRAS logs out a user or a user goes offline from the BRAS due to a network fault. In this case, the CPE cannot detect that the user has gone offline from the BRAS and still sends a Rebind message to the BRAS after the timer expires. To allow the CPE to detect a user logout immediately after the user goes offline from the BRAS, run the dhcpv6 rebind no-user action reply command. Then, after receiving a Rebind message, the BRAS responds with a Reply message indicating a status of NoBinding, prompting the CPE to re-dial up for IP address application.

Procedure

Configure transparent transmission of DHCPv6 packets.
1. Run system-view
  The system view is displayed.
2. Run dhcpv6 through-packet
  The function to transparently transmit DHCPv6 packets is configured.
3. Run dhcpv6 solicit-speed-threshold threshold-value value
  The speed threshold at which Solicit packets are received is configured.
  
  The more Solicit packets are sent within a specified time period, the faster users go online.
4. Run commit
  The configuration is committed.
Configure unicast communication and two-message exchange between a DHCPv6 client and a DHCPv6 server.
1. Run system-view
  The system view is displayed.
2. Run ipv6 pool pool-name { bas { local | delegation | relay } }
  An IPv6 address pool is created, and the IPv6 address pool view is displayed.
3. (Optional) Run dhcpv6 unicast-option
  The unicast option is configured on the DHCPv6 server. Then, the DHCPv6 server can receive unicast DHCPv6 messages and instruct the DHCPv6 clients to communicate with the DHCPv6 server in unicast mode.
4. (Optional) Run dhcpv6 rapid-commit
  The DHCPv6 server is configured to support rapid two-message exchange (solicit, reply).
5. Run commit
  The configuration is committed.
Enable a CPE to detect a user logout immediately after the user goes offline from the BRAS.
1. Run system-view
  The system view is displayed.
2. Run dhcpv6 rebind no-user action reply
  The device is enabled to send a DHCPv6 Reply message indicating a status of NoBinding in response to a client's DHCPv6 Rebind message if no corresponding user entry exists on the device.
3. Run commit
  The configuration is committed.