How are VRRP packets of an S series switch sent in a super-VLAN

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For S series switches (except the S1700), you are not advised to create a VRRP group on the corresponding VLANIF interface for a super-VLAN. If such a VRRP group has been created, the total number of VLANs (including common VLANs, super-VLANs, and sub-VLANs) in the VRRP group cannot exceed 256 to minimize impact on host performance.
By default, if a VRRP group is configured for a super-VLAN, the master switch sends VRRP Advertisement packets to the super-VLAN's sub-VLAN that is in Up state and has the smallest VLAN ID among all the sub-VLANs. You can run a related command to configure VRRP Advertisement packets to be sent in a specified sub-VLAN. This prevents VRRP Advertisement packets from being broadcast in all sub-VLANs, reducing network bandwidth consumption. The configuration procedure is as follows:
1. Run the system-view command to enter the system view.
2. Run the interface vlanif vlan-id command to enter the VLANIF interface view.
3. Run the vrrp advertise send-mode { sub-vlan-id | all } command to configure a mode in which the master switch sends VRRP Advertisement packets in a super-VLAN.
- sub-vlan-id: specifies the ID of a sub-VLAN where the master switch sends VRRP Advertisement packets.
- all: indicates that the master switch sends VRRP Advertisement packets to all sub-VLANs in a super-VLAN.
Note: The parameter all is not recommended. If all is configured, a super-VLAN broadcasts a VRRP Advertisement packet to all its sub-VLANs, which increases bandwidth usage.

Other related questions:
Why VRRP heartbeat packets cannot be transmitted normally between VRRP master and backup devices when VRRP packets are sent in a Super-VLAN
For S series switches, by default, VRRP Advertisement packets of a super-VLAN are sent only to the sub-VLAN that has the smallest VLAN ID among all the sub-VLANs in Up state. VRRP heartbeat packets cannot be transmitted normally between VRRP master and backup devices when the link between them does not allow the first Sub-VLAN of the Super-VLAN. The vrrp advertise send-mode command can be used to cancel or configure the mode in which VRRP Advertisement packets of a super-VLAN are sent.

Can DHCP relay and DHCP server be configured in a super-VLAN on an S series switch
On S series switches excluding the S1700, DHCP relay and DHCP server be configured on the VLANIF interface of a super-VLAN since V100R003.

MTU value of OSPF DD packets sent by S series switches
According to RFC 2328, the value of the Interface MTU field in a DD packet is the MTU value of the link (if the link is a virtual link, the value is 0). When a device receives a DD packet with an Interface MTU value larger than the MTU value in DD packets sent by the device, the device drops the DD packet and the neighbor status stays Exchange Start. On an S series switch supporting OSPF, you can run the ospf mtu-enable command in an interface view to check the MTU value in received DD packets. By default, OSPF does not check the MTU value in a DD packet. If the MTU match check is not performed, LSDBs of the two ends can be synchronized and the OSPF neighbor relationship can enter the Full state with the MTU values configured on the two ends varying slightly.

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