H3C Technologies H3C SecPath F1000-E - Manual (Page 11)

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• The MAC address learned by Host C is the virtual MAC address of Router C, thus ensuring that the
packets from Host C are forwarded by Router C.
Virtual Forwarder
When working in load balancing mode, VRRP uses VFs to implement load balancing. Each VF associates
with a virtual MAC address in the VRRP group and forwards packets destined to this virtual MAC
address.
The master assigns virtual MAC addresses to all routers (including the master and the backups) in the
VRRP group. After learning its virtual MAC address, a router in the VRRP group creates a VF that
corresponds to this MAC address, and then the becomes the owner of this VF.
VF weight and priority
The weight of a VF indicates the forwarding capability of a router: the higher the weight, the higher the
forwarding capability. When the weight is lower than the lower limit of failure, the router cannot be
capable of forwarding packets for the hosts.
The priority of a VF determines the VF state: a VF with the highest priority is in the active state and is
known as the active virtual forwarder (AVF), which forwards packets; other VFs are in the listening state
and are known as the listening virtual forwarders (LVFs), which listen to the state of the AVF. The priority
value of a VF ranges from 0 to 255, where 255 is reserved for the VF owner.
The priority value of a VF is calculated based on its weight.
VF backup
If the weight of the VF owner is no less than the lower limit of failure, the priority of the VF owner is the
highest value 255. Therefore, the VF owner is the AVF and forwards packets destined to the MAC
address of the AVF. When receiving the advertisements sent by the AVF, other routers in the VRRP group
create their own VFs, which are in the listening state. Figure 8 illustrates the VF information on each router
in the VRRP group.
Figure 8 VF information