H3C Technologies H3C S12500 Series Switches - Manual (Page 148)

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the routers. Each VF associates with a virtual MAC address in the VRRP group and forwards packets
destined to this virtual MAC address.
The following describes how VFs are created on the routers in a VRRP group:
1. The master assigns virtual MAC addresses to all routers 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
becomes the owner of this VF.
2. The router advertises the VF information to the other routers in the VRRP group.
3. After receiving the VF advertisement, each of the other routers creates the advertised VF.
As described in the preceding steps, each router in the VRRP group creates not only a VF corresponding
to its virtual MAC address, but also VFs advertised by the other routes in the VRRP group.
VF weight and priority
The weight of a VF indicates the forwarding capability of a router. A higher weight indicates a higher
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. Among the VFs that correspond to the same virtual MAC
address on different routers in the VRRP group, the 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 monitor the state of the AVF. The priority
value of a VF ranges from 0 to 255, where 255 is reserved for the VF owner. If the weight of a VF owner
is higher than or equal to the lower limit of failure, the priority value of the VF owner is 255.
The priority value of a VF is calculated based on its weight:
• If the weight of a VF is higher than or equal to the lower limit of failure, and the router where the VF
resides is the owner of the VF, the priority value of the VF is 255.
• If the weight of a VF is higher than or equal to the lower limit of failure, but the router where the VF
resides is not the owner of the VF, the priority value of the VF is weight/(number of local AVFs +1)
• If the weight of a VF is lower than the lower limit of failure, the priority value of the VF is 0.
VF backup
The VFs corresponding to a virtual MAC address on different routers in the VRRP group back up one
another.