H3C Technologies H3C SecPath F1000-E - Manual (Page 10)

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NOTE:
VRRP load balancing mode is based on VRRP standard protocol mode, so mechanisms, such as master
election, preemption, and tracking functions, in the standard protocol mode are also supported in the load
balancing mode. In addition, VRRP load balancing mode has new mechanisms, which are introduced in
the following sections.
Assigning Virtual MAC Addresses
When VRRP works in load balancing mode, the master assigns virtual MAC addresses to routers in the
VRRP group and answers the ARP requests (for the IPv4 network) or ND requests (for the IPv6 network)
from different hosts. The backup routers, however, do not answer the ARP requests (for the IPv4 network)
or ND requests (for the IPv6 network) from the hosts.
Figure 7 Allocating virtual MAC addresses
As shown in
Figure 7 , 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 assigns different virtual MAC addresses to Routers A,
B and C.
Host A, Host B, and Host C send ARP requests to learn the MAC address that corresponds to the gateway
with the virtual IP address 10.1.1.1. The master (Router A) answers ARP requests of the hosts by using
different virtual MAC addresses.
• The MAC address learned by Host A is the virtual MAC address of Router A, which means Host A
uses the virtual MAC address of Router A as the MAC address of the gateway, thus ensuring that the
packets from Host A are forwarded by Router A.
• The MAC address learned by Host B is the virtual MAC address of Router B, thus ensuring that the
packets from Host B are forwarded by Router B.