R3204P16-HP Load Balancing Module High Availability Configuration Guide-6PW101

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Figure 6 Allocating virtual MAC addresses
As shown in Figure 6, the virtual IP address of the VRRP group is 10.1.1.1/24; Router A is the master;
Router B and Router C are the backups. Router A allocates different virtual MAC addresses to Routers A,
B and C.
Host A, Host B, and Host C send ARP requests to obtain the MAC address corresponding to the gateway
with the virtual IP address 10.1.1.1. The master (Router A) replies ARP requests of the hosts with different
virtual MAC addresses.
• The MAC address obtained by Host A is the virtual MAC address of Router A, that is, Host A takes
the virtual MAC address of Router A as the MAC address of the gateway, and thus to ensure that
the packets from Host A are forwarded by Router A.
• The MAC address obtained by Host B is the virtual MAC address of Router B, and thus to ensure
that the packets from Host B are forwarded by Router B.
• The MAC address obtained by Host C is the virtual MAC address of Router C, and thus to ensure
that the packets from Host C are forwarded by Router C.
Virtual forwarder
When working in the load balancing mode, VRRP uses VFs to realize load balancing. Each VF associates
with a virtual MAC address of the VRRP group and forwards packets destined to this virtual MAC
address.
The master allocates virtual MAC addresses to all routers (including the master and the backups) in the
VRRP group. After obtaining its virtual MAC address, a router in the VRRP group will create a VF
corresponding to this MAC address, and then the router becomes the owner of this VF.
1. 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 a specified value which is the lower limit of failure,
the router will not be capable of forwarding packets for the hosts.