The nd user-bind detect enable command enables the function for automatically detecting status of users mapping ND snooping dynamic binding entries.
The undo nd user-bind detect enable command disables the function for automatically detecting status of users mapping ND snooping dynamic binding entries.
By default, the function for automatically detecting status of users mapping ND snooping dynamic binding entries is disabled.
Usage Scenario
After ND snooping is enabled, the device snoops NS packets in the DAD process to establish ND dynamic binding entries. The aging time of an ND snooping dynamic binding table depends on the IPv6 address lease. If the address lease does not expire but the user is offline, the ND snooping dynamic entry mapping the user cannot be deleted, which occupies binding entry resources on the device.
To prevent this problem, you can enable the automatic user status detection for users mapping ND snooping dynamic binding entries on the device. After this function is enabled, the device sends NS packets to the user according to the detection times (n) specified in nd user-bind detect and detection interval. If the device receives no NA packet from the user after sending the NS packets n times, the device considers the user to be offline and deletes the dynamic ND snooping binding entry matching the user.
Precautions
After you run the nd user-bind detect enable command, the device sends an NS packet after a period of time. The maximum value of this period is 20 seconds.