Vrrp Tracking; Vrrp Application - HPE FlexFabric 5700 Series Configuration Manual

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If the backup does not receive any VRRP advertisement when the timer (3 × advertisement
interval + Skew_Time) expires, it becomes the master.
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If the backup receives a VRRP advertisement with a greater or the same priority within the timer
(3 × advertisement interval + Skew_Time), it remains a backup.
•
If the backup receives a VRRP advertisement with a smaller priority within the timer (3 ×
advertisement interval + Skew_Time), it remains a backup when operating in non-preemptive
mode, or becomes the master when operating in preemptive mode.
The elected master starts a VRRP advertisement interval to periodically send VRRP advertisements
to notify the backups that it is operating correctly. Each of the backups starts a timer to wait for
advertisements from the master.
After a backup receives a VRRP advertisement, it compares only the priority in the packet with its
own priority.
When multiple routers in a VRRP group declare that they are the master because of network
problems, the one with the highest priority becomes the master. If two routers have the same priority,
the one with the highest IP address becomes the master.

VRRP tracking

To enable VRRP tracking, configure the routers in the VRRP group to operate in preemptive mode
first, so that only the router with the highest priority operates as the master for packet forwarding. For
more information about track entries, see High Availability Configuration Guide.
The VRRP tracking function uses network quality analyzer (NQA) or bidirectional forwarding
detection (BFD) to monitor the state of the master, and establishes the collaboration between the
VRRP device state and NQA or BFD through the track function. It implements the following:
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Monitors the upstream link and changes the priority of the router according to the state of the
link. If the upstream link fails, the hosts on the subnet cannot access external networks through
the router and the state of the track entry becomes Negative. The priority of the master
decreases by a specified value. Then, a router with a higher priority in the VRRP group
becomes the master to maintain the proper communication between the hosts on the subnet
and external networks.
•
Monitors the state of the master on the backups. When the master fails, a backup immediately
takes over as the master to ensure uninterrupted communication.
When the track entry changes from Negative to Positive or Notready, the router automatically
restores its priority. For more information about track entries, see

VRRP application

Master/backup
In master/backup mode, only the master forwards packets, as shown in
fails, a new master is elected from among the backups. This mode requires only one VRRP group,
and each router in the group has a different priority. The one with the highest priority becomes the
master.
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"Configuring Track."
Figure 31. When the master