VRRP protocol
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VRRP
PROTOCOL
C
ONFIGURATION
Imola supports the VRRP (Virtual Router Redundancy Protocol, RFC 2338) protocol, a standard
protocol which allows that different routers in a LAN can dynamically have the function to reply to
specific IP addresses.
In a redundant configuration there is a
Master
node and one or more
Backup
nodes.
When the VRRP protocol is activated (Initial status) all the nodes send packets to a group address,
specifying a priority value necessary to decide which node will have the role of Master: the node
which has the highest priority value becomes the Master. This activates a virtual IP address on the
configured interface and through this interface, it continues to send packets (advertisement
packets) towards the group address (multicast), while the backup nodes continue to listen.
If a backup node no longer receives advertisement packets or it receives them with a lower priority
value than its own, it assumes the role of Master. In the same way, if the master node receives some
advertisements with a higher priority value than the one it owns, it becomes a backup.
In order to configure the interface on which activate the protocol, the command is:
set vrrp interface <ifname>
where
ifname
can be eth0 or eth1 or the name of a VLAN interface of type eth1.N.
In order to set the interval between two advertisement packets, the command is:
set vrrp delay N
The backup will detect the unavailability of the master after
3 delays
. The default is
1sec.
In order to set the priority the command is:
set vrrp priority N
The value
N
can be from
1
to
254
. The higher is the value the higher is the priority.
The command
set vrrp vrid N
identify the VRRP group. It is a value between
1
and
254
.
The command:
set vrrp vipaddr 10.10.2.90
configures the virtual IP address which will be activated on the configured interface in case if the
role of master is assumed.
The command:
set vrrp vmac
associates to the Virtual address the virtual MAC Address like
00:00:5E:01:01:VV
, where
VV
it is
the value of the
vrid
parameters.
To enable the pre-shared-key authentication: