Load balancing means multiple routers undertake workloads simultaneously. Therefore,
two or more backup groups are needed to realize load balancing. Each backup group
consists of one master router and several backup routers. Master router can vary from one
backup group to the others.
Figure 10-59 VRRP Load Balancing
A router owns different priority in different backup groups when it participates in multiple
VRRP backup groups simultaneously.
In Figure 10-58, there exist three backup groups:
•
Backup Group 1, corresponding to Virtual Router 1. Device A is the master router;
Device B and C are backup routers.
•
Backup Group 2, corresponding to Virtual Router 2. Device B is the master router;
Device A and C are backup routers.
•
Backup Group 3, corresponding to Virtual Router 3. Device C is the master router;
Device A and B are backup routers.
To realize the workload balancing among Device A, B and C, the default gateway of the
hosts associated with the LAN should be set as Virtual Router 1, 2 and 3 respectively. When
it comes to priority configuration, it would be better that the VRRP priority values of the
three virtual routers are different in order to prevent one router from being more than one
master simultaneously.
VRRP Configuration
Before configuring VRRP, users should plan well to specify the role and function of the devices
in backup groups. Every switch in backup group should be configured, which is the
precondition to construct a backup group.
10.10.1
Basic Config
VRRP (Virtual Routing Redundancy Protocol) is a function on the switch that dynamically
assigns responsibility for a virtual router to one of the VRRP routers on a LAN. The VRRP router
that controls the IP address associated with a virtual router is called the Master, and will
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