(Optional) Configuring VRRP6 Time Parameters

Context

You can set VRRP6 time parameters as needed. Table 1 lists application scenarios of VRRP6 time parameters.

**Table 1** Application scenarios of VRRP6 time parameters
Function	Application Scenario
Interval at which VRRP6 Advertisement packets are sent	The master in a VRRP6 group sends VRRP6 Advertisement packets to backups at intervals to notify that it is working properly. After the Master_Down_Interval timer expires, a new master is selected from the backups if the backups do not receive VRRP6 Advertisement packets. Heavy network traffic or time differences on different devices may result in the backup status change due to timeout of VRRP6 Advertisement packets. When packets from the original master reach the new master, the status of the new master changes. You can increase the interval to solve this problem.
Interval at which ND packets are sent by the master	To ensure that MAC address entries on the downstream switch are correct, the master in a VRRP6 group periodically sends ND packets to update MAC address entries on the downstream switch.
Delay before a VRRP6 group recovers	On an unstable network, frequent flapping of the BFD session status or interface status monitored by a VRRP6 group may result in frequent switching of the VRRP6 group status. After the delay is set, the VRRP6 group does not immediately respond to an interface or BFD session Up event. Instead, the VRRP6 group processes this event after the delay. This prevents frequent switching of the VRRP6 group status.

Procedure

Set the interval at which VRRP6 Advertisement packets are sent.
1. Run system-view
  The system view is displayed.
2. Run interface interface-type interface-number
  The interface view is displayed.
3. (Optional) On an Ethernet interface, run undo portswitch
  The interface is switched to Layer 3 mode.
  
  By default, an Ethernet interface works in Layer 2 mode.
  
  Only the S5720-EI, S5720-HI, S5730-HI, S5731-H, S5731-S, S5731S-H, S5731S-S, S5732-H, S6720-EI, S6720-HI, S6720S-EI, S6730-H, S6730S-H, S6730-S, and S6730S-S support switching between Layer 2 and Layer 3 modes.
4. Run vrrp6 vrid virtual-router-id timer advertise advertise-interval
  The interval at which VRRP6 Advertisement packets are sent is set.
  
  By default, the interval is 1 second.
  
  If devices in a VRRP6 group use different intervals, VRRP6 may not work.
Set the interval at which ND packets are sent by the master.
1. Run system-view
  The system view is displayed.
2. Run vrrp gratuitous-arp timeout time
  The interval at which ND packets are sent by the master is set.
  
  By default, the master sends ND packets every 120s.
  
  The interval at which the master sends ND packets must be shorter than the aging time of ND entries on each user device.
  - To restore the default interval at which an ND packet is sent, run the undo vrrp gratuitous-arp timeout command in the system view.
  - To disable the master from sending ND packets, run the vrrp gratuitous-arp timeout disable command in the system view.
Set the delay before a VRRP6 group recovers.
1. Run system-view
  The system view is displayed.
2. Run vrrp recover-delay delay-value
  The delay before a VRRP6 group recovers is set.
  
  By default, the delay before a VRRP6 group recovers is 0.
  - After this command is used, all VRRP6 groups on the device are configured with the same delay.
  - When the device in a VRRP6 group restarts, VRRP6 status flapping may occur. It is recommended that the delay be set based on actual networking.