(Optional) Setting the Time for Listing to an NA Packet in Response to Duplicate Addresses

The time for listing to an NA packet in response to duplicate addresses can be set only in SLAAC-Only scenarios or DHCPv6+SLAAC scenarios.

• In SLAAC-Only scenarios:

  When obtaining an IP address in SLAAC mode, an ND client generates the IPv6 address based on the prefix in the RA packet. After the IPv6 address is generated, the ND client sends an NS packet to check whether duplicate addresses exist on the network. When detecting the NS packet in the DAD process from the ND client, the device generates an ND snooping entry, sets the entry to the detect state, and listens to the mapping NA packet.

  • If a mapping NA packet is detected in the configured listening period, IPv6 address conflict occurs and the device deletes this ND snooping entry.
  • If no mapping NA packet is detected in the configured listening period, the IPv6 address is available and the device sets the ND snooping entry to the bound state. The device deletes the ND snooping entry only when the entry ages out. If automatic user status detection for users mapping ND snooping dynamic binding entries is enabled using the nd user-bind detect enable command on the device, and no NA packet is returned from the user after NS packets are sent for times configured using the nd user-bind detect retransmit retransmit-times interval retransmit-interval command, the device considers that the user is not online and deletes the mapping ND snooping entry.

• In DHCPv6+SLAAC scenarios:

  • The procedure for processing packets by SAVI in SLAAC mode is the same as that in SLAAC-Only scenarios.

  • When obtaining an IP address in DHCPv6 mode, a DHCPv6 client may send an NS packet to check whether duplicate addresses exist on the network. When detecting the NS packet in the DAD process from the DHCPv6 client, the device sets the mapping DHCPv6 snooping entry to the detect state, and listens to the mapping NA packet.

    • If a mapping NA packet is detected in the configured listening period, IPv6 address conflict occurs and the device deletes this DHCPv6 snooping entry.
    • If no mapping NA packet is detected in the configured listening period, the IPv6 address is available and the device sets the DHCPv6 snooping entry to the bound state. The device deletes the DHCPv6 snooping entry only when detecting the DHCPv6 Decline packet or DHCPv6 Release packet from the DHCPv6 client.