H3C Technologies H3C SecPath F1000-E - Manual (Page 12)

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LVFs listen to the AVF. When the AVF fails, the LVFs elect the LVF with the highest priority value as the new
AVF.
A VF always works in the preemption mode. When an LVF finds its priority higher than that in the
advertisement sent by the AVF, the LVF declares itself as the AVF.
VF tracking
The AVF forwards packets destined to the MAC address of the AVF. If the uplink of the AVF fails and no
LVF is notified to take over the AVF's work, hosts (on the LAN) that use the MAC address of the AVF as
their gateway MAC address cannot access the external network.
This problem can be solved by the VF tracking function. You can monitor the uplink state by using
network quality analyzer (NQA) and bidirectional forwarding detection (BFD), and establish the
collaboration between the VF and the NQA or between the VF and the BFD through the tracking function.
When the uplink fails, the state of the monitored track entry changes to negative and the weight of the
VF decreases by a specified value. Then, the VF with a higher priority becomes the AVF and forwards
packets.
Packet Types
VRRP standard protocol mode defines only one type of packet: VRRP advertisement. Only the master in
a VRRP group periodically sends VRRP advertisements, and the backups do not send VRRP
advertisements.
VRRP load balancing mode defines four types of packets:
• Advertisement: VRRP advertises VRRP group state and information about the VF that is in the active
state. Both the master and the backups periodically send VRRP advertisements.
• Request: If a backup is not the VF owner, it sends a request to ask the master to assign a virtual MAC
address.
• Reply: When receiving a request, the master sends a reply to the backup router to assign a virtual
MAC address. Upon receiving the reply, the backup router creates a VF that corresponds to the
virtual MAC address, and then becomes the owner of this VF.
• Release: When a VF owner fails, the router that takes over its responsibility sends a release after a
specified period of time to notify the other routers in the VRRP group to delete the VF of the failed
VF owner.
NOTE:
The format of the above four types of packets is similar to that of the advertisement in VRRP standard
protocol mode except that a packet used in load balancing mode is appended with option field, which
contains information for load balancing.
Configuring VRRP for IPv4
VRRP for IPv4 Configuration Task List
To form a VRRP group, perform the following configurations on each device in the VRRP group.
Complete these tasks to configure VRRP for IPv4: