Vrrp Standard Mode; Router Priority In A Vrrp Group; Preemption - HP 5900 Series Configuration Manual

Standard mode—Implemented based on RFCs. For more information, see
•
• Load balancing mode—Extends the VRRP standard mode to distribute load across VRRP group
members. For more information, see
VRRP has two versions: VRRPv2 and VRRPv3. VRRPv2 supports IPv4 VRRP. VRRPv3 supports IPv4 VRRP
and IPv6 VRRP.

VRRP standard mode

In VRRP standard mode, only the master in the VRRP group can provide gateway service. When the
master fails, the backup routers elect a new master to take over for nonstop gateway service.
Figure 19 VRRP networking
As shown in
address. Hosts on the subnet use the virtual router as the default gateway.
The router with the highest priority among the three routers is elected as the master, and the other two are
backups.

Router priority in a VRRP group

VRRP determines the role (master or backup) of each router in a VRRP group by priority. A router with
higher priority is more likely to become the master.
VRRP priorities range from 0 to 255, and a greater number represents a higher priority. Priorities 1 to
254 are configurable. Priority 0 is reserved for special uses, and priority 255 is for the IP address owner.
The router acting as the IP address owner in a VRRP group always has a running priority of 255 and acts
as the master as long as it operates correctly.

Preemption

A router in a VRRP group operates in either non-preemptive mode or preemptive mode:
• Non-preemptive mode—When a router in the VRRP group becomes the master, it acts as the master
as long as it operates correctly, even if a backup router is later assigned a higher priority.
Non-preemptive mode helps avoid frequent switchover between the master and backup routers.
Figure 19, Router A, Router B, and Router C form a virtual router, which has its own IP
"VRRP load balancing
70
"VRRP standard
mode."
mode."