Digisol DG-GS4826S, Management Manual

Page: 509 / 1344

C
HAPTER
19 | Configuring Router Redundancy
Configuring VRRP Groups
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priority. In cases where the configured priority is the same on several
group members, then the master router with the highest IP address is
selected from this group.
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If you have multiple secondary addresses configured on the current
VLAN interface, you can add any of these addresses to the virtual
router group.
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The interfaces of all routers participating in a virtual router group must
be within the same IP subnet.
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VRRP creates a virtual MAC address for the master router based on a
standard prefix, with the last octet equal to the group ID. When a
backup router takes over as the master, it continues to forward traffic
addressed to this virtual MAC address. However, the backup router
cannot reply to ICMP pings sent to addresses associated with the virtual
group because the IP address owner is off line.
Virtual Router Priority –
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The Owner of the virtual IP address is automatically assigned the
highest possible virtual router priority of 255. The backup router with
the highest priority will become the master router if the current master
fails. However, because the priority of the virtual IP address Owner is
the highest, the original master router will always become the active
master router when it recovers.
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If two or more routers are configured with the same VRRP priority, the
router with the higher IP address is elected as the new master router if
the current master fails.
Preempting the Acting Master –
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The virtual IP Owner has the highest priority, so no other router can
preempt it, and it will always resume control as the master virtual
router when it comes back on line. The preempt function only allows a
backup router to take over from a master router if no router in the
group is the virtual IP owner, or from another backup router that is
temporarily acting as the group master. If preemption is enabled and
this router has a higher priority than the current acting master when it
comes on line, it will take over as the acting group master.
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You can add a delay to the preempt function to give additional time to
receive an advertisement message from the current master before
taking control. If the router attempting to become the master has just
come on line, this delay also gives it time to gather information for its
routing table before actually preempting the currently active master
router.
P
ARAMETERS
These parameters are displayed in the web interface:
Adding a VRRP Group
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VRID – VRRP group identifier. (Range: 1-255)