Samsung Ubigate iBG2016, Configuration Manual

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Ubigate iBG2016 Configuration Guide
© SAMSUNG Electronics Co., Ltd.
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CHAPTER 8. VRRP
In statically routed networks, when a router fails, all the network devices
connected to this router are unable to have traffic routed. Typically this means
these devices cannot reach the Internet or other networks.
IPv4’s Virtual Router Redundancy Protocol(VRRP) eliminates this single
point of failure by dynamically assigning virtual routers that can provide
network connectivity in the event the primary router fails. One virtual router is
designated as the Master which is assigned the IP addresses of connected
devices. The Master router can manage multiple primary and secondary IP
addresses.
Alternate virtual routers(up to 254) are designated as backup virtual routers in
the event the Master fails. Each backup is configured with a priority setting
that determines the order in which backup routers take over in the event the
Master fails. When the Master router fails, the backup router with the smallest
priority number will preempt all other backup routers in assuming the duties
of the Master router. If you disable the preempt feature(using the no vrrp
preempt command), the backup virtual router that is configured as the Master
virtual router will remain such until the original Master virtual router recovers.
The mechanism by which virtual routers in the same network communicate
status and priority is through VRRP advertisements from the Master virtual
router. VRRP uses the assigned multicast address 224.0.0.18. By default, these
advertisements are sent every second, but you can configure the interval.
In addition to maintaining network connectivity when a router fails, VRRP
allows network administrators to share routing duties with multiple routers
thereby reducing the impact of heavy traffic loads.