HP 6125XLG R2306-HP 6125XLG Blade Switch High Availability Configuration Guide - Page 46

VRRP standard mode, Router priority in a VRRP group, Preemption

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• Load balancing mode-Extends the VRRP standard mode to distribute load across VRRP group members. For more information, see "VRRP load balancing mode." 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 13 VRRP networking As shown in Figure 13, Router A, Router B, and Router C form a virtual router, which has its own IP 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. The value range for VRRP priorities is 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 properly. 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 properly, even if a backup router is later assigned a higher priority. Non-preemptive mode helps avoid frequent switchover between the master and backup routers. 41

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41
•
Load balancing mode
—Extends the VRRP standard mode to distribute load across VRRP group
members. For more information, see "
VRRP load balancing mode
."
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 13
VRRP networking
As shown in
Figure 13
, Router A, Router B, and Router C form a virtual router, which has its own IP
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.
The value range for VRRP priorities is 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 properly.
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 properly, even if a backup router is later assigned a higher priority.
Non-preemptive mode helps avoid frequent switchover between the master and backup routers.