Vrrp Application (Taking Ipv4-Based Vrrp For Example) - HP A5830 series Configuration Manual

If the uplink interface of a router in a VRRP group fails, usually the VRRP group cannot be aware of the
uplink interface failure. If the router is the master of the VRRP group, hosts on the LAN are not able to
access external networks because of the uplink failure. This problem can be solved by tracking a
specified uplink interface. If the tracked uplink interface is down or removed, the priority of the master is
decreased automatically by a specified value and a higher priority router in the VRRP group becomes
the master.
Tracking a track entry
By monitoring a track entry, you can do the following:
Monitor an uplink and change the priority of the router according to the state of the uplink. If the
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uplink fails, hosts in the LAN cannot access external networks through the router. In this case, the
state of the monitored track entry is negative and the priority of the router decreases by a specified
value. Then, a higher priority router in the VRRP group becomes the master to maintain the proper
communication between the hosts in the LAN and external networks.
Monitor the master on a backup. When the master fails, the backup immediately preempts as the
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master to maintain normal communication.
For more information about track entries, see the chapter "Track configuration."

VRRP application (taking IPv4-based VRRP for example)

Master/backup
In master/backup mode, only the master forwards packets. When the master fails, a new master is
elected from the backups. This mode requires only one VRRP group, in which each router holds a
different priority and the one with the highest priority becomes the master, as shown in
Figure 33 VRRP in master/backup mode
Assume that Router A is the master and, therefore, can forward packets to external networks, whereas
Router B and Router C are backups and are thus in the state of listening. If Router A fails, Router B and
Router C elect for a new master to forward packets to hosts on the LAN.
Load sharing
More than one VRRP group can be created on an interface of a router to allow the router to be the
master of one VRRP group, but a backup of another at the same time.
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Figure 33.