HPE FlexNetwork HSR6800 series Configuration Manual page 143

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Type—Type of the VRRP packet. It must be VRRP advertisement, represented by 1.
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Virtual Rtr ID (VRID)—ID of the virtual router. It ranges from 1 to 255.
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Priority—Priority of the router in the VRRP group, in the range 0 to 255. A greater value
represents a higher priority.
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Count IP Addrs/Count IPv6 Addrs—Number of virtual IPv4 or IPv6 addresses for the VRRP
group. A VRRP group can have multiple virtual IPv4 or IPv6 addresses.
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Auth Type—Authentication type. For IPv4 VRRPv2, 0 means no authentication, 1 means
simple text authentication, and 2 means MD5 authentication. For IPv6 VRRPv2, 0 means no
authentication and 1 means simple text authentication. IPv4/IPv6 VRRPv3 does not support
authentication, and this field is reserved.
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Adver Int—Interval for sending advertisement packets. For IPv4 VRRPv2, the interval is in
seconds and defaults to 1. For other VRRP versions, the interval is in centiseconds and defaults
to 100.
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Checksum—16-bit checksum for validating the data in VRRP packets.
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IP Address/IPv6 Address—Virtual IPv4 or IPv6 address entry of the VRRP group. The Count
IP Addrs or Count IPv6 Addrs field defines the number of virtual IPv4 or IPv6 addresses.
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Authentication Data—Authentication key. This field is used only for simple authentication and
is 0 for any other authentication mode. IPv4/IPv6 VRRPv3 packets do not provide this field.
VRRP principles
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Routers in a VRRP group determine their roles by priority. The router with the highest priority is
the master, and the others are the backups. The master periodically sends VRRP
advertisements to notify the backups that it is working correctly, and each of the backups starts
a timer to wait for advertisements from the master.
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In preemptive mode, when a backup receives a VRRP advertisement, it compares the priority in
the packet with its own priority. If the priority of the backup is higher, the backup becomes the
master. Otherwise, it remains as a backup. In preemptive mode, a VRRP group always has the
router with the highest priority as the master for forwarding packets.
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In non-preemptive mode, a backup with higher priority than the master does not preempt the
master if the master correctly working. The non-preemptive mode avoids frequent switchover
between the master and backups.
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If the timer of a backup expires but the backup still does not receive any VRRP advertisement,
it considers that the master failed. In this case, the backup considers itself as the master and
sends VRRP advertisements to start a new master election.
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When multiple routers in a VRRP group declare that they are the master because of
inconsistent configuration or 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.
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When a backup router receives an advertisement, it compares its priority with the advertised
priority. If its priority is higher, it takes over the master.
VRRP tracking
To enable VRRP tracking, first configure the routers in the VRRP group to operate in preemptive
mode, so that the router with the highest priority always operates as the master for forwarding
packets.
1. Tracking a specified interface
The interface tracking function expands the backup functionality of VRRP. It provides backup
not only when the interface to which a VRRP group is assigned fails, but also when other
interfaces (such as uplink interfaces) on the router become unavailable.
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
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