Westermo RedFox Series - Manual (Page 667)

Westermo OS Management Guide
Version 4.17.0-0
To avoid that multiple master routers appear on an IP subnet, a WeOS VRRP router
will refrain from becoming master if it hears another router with mismatching
VRRP authentication information.
30.1.5 VRRP Synchronisation Groups
VRRP synchronisation is a function to keep the VRRP role (master vs backup) the
same for different VRRP instances on the same unit, see
fig. 30.2 .
R1
(Master)
192.168.55.3
Priority 150
Virtual IP:
VRID: 33
Virtual IP:
Priority 100
(Backup)
VRID: 33
(Master)
192.168.1.3
Priority 150
Virtual IP:
VRID: 1
192.168.1.3
Virtual IP:
Priority 100
(Backup)
VRID: 1
.1 .2
H
192.168.1.0/24 .78
Default GW:
192.168.1.3
(i.e., "VIP")
R2
.1 .2
192.168.55.0/24
192.168.55.3
Figure 30.2: Illustrating a topology using synchronised groups. Both instances
on R1 will always remain in master state as long no fault is detected (e.g. link
down). On fault R1 will become backup on both instances and R2 will become
master for both instances.
A synchronisation group consists of two VRRP instances. These two instances
should be active on different VLAN network interfaces, e.g. VRID 1 on interface
vlan1 can be synchronized with VRID 33 on interface vlan2. The VRRP instances
on a unit will only take the master role if it considers itself to have the highest
VRRP priority for both instances. If one of the VRRP instances in the synchronisa-
tion group would transistion to backup state (e.g. link down), the other instance
will also change state to backup, i.e. the instances in the synchronisation group
will always have the same state.
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