H3C Technologies H3C MSR 5600 - Manual (Page 16)

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Figure 7 Sending packets to different routers for forwarding
Virtual forwarder
Virtual forwarder creation
Virtual MAC addresses enable traffic distribution across routers in a VRRP group. To enable routers in the
VRRP group to forward packets, VFs must be created on them. Each VF is associated with a virtual MAC
address in the VRRP group and forwards packets that are sent to this virtual MAC address.
VFs are created on routers in a VRRP group, as follows:
1. The master assigns virtual MAC addresses to all routers in the VRRP group. Each member router
creates a VF for this MAC address and becomes the owner of this VF.
2. Each VF owner advertises its VF information to the other member routers.
3. After receiving the VF advertisement, each of the other routers creates the advertised VF.
Eventually, every member router maintains one VF for each virtual MAC address in the VRRP group.
VF weight and priority
The weight of a VF indicates the forwarding capability of a VF. A higher weight means higher
forwarding capability. When the weight is lower than the lower limit of failure, the VF cannot forward
packets.
The priority of a VF determines the VF state. Among the VFs created on different member routers for the
same virtual MAC address, the VF with the highest priority, known as the active virtual forwarder (AVF),
is in active state to forward packets, and all other VFs listen to the state of the AVF and are known as the
listening virtual forwarders (LVFs). VF priority is in the range of 0 to 255, where 255 is reserved for the
VF owner. When the weight of a VF owner is higher than or equal to the lower limit of failure, the priority
of the VF owner is 255.
The priority of a VF is calculated based on its weight:
• On the router that owns the VF, if the weight of the VF is higher than or equal to the lower limit of
failure, the priority of the VF is 255.