Dell BigIron RX Series, Руководство по настройке

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456 BigIron RX Series Configuration Guide
53-1002253-01
Overview of VRRPE
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VRRPE uses UDP to send Hello messages in IP multicast messages. The Hello packets use
the interface’s actual MAC address and IP address as the source addresses. The
destination MAC address is 01-00-5E-00-00-02, and the destination IP address is
224.0.0.2 (the well-known IP multicast address for “all routers”). Both the source and
destination UDP port number is 8888. VRRP messages are encapsulated in the data
portion of the packet.
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Track ports and track priority:
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VRRP changes the priority of the VRID to the track priority, which typically is lower than the
VRID priority and lower than the VRID’s priorities configured on the Backups. For example,
if the VRRP interface’s priority is 100 and a tracked interface with track priority 20 goes
down, the software changes the VRRP interface’s priority to 20.
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VRRPE reduces the priority of a VRRPE interface by the amount of a tracked interface’s
priority if the tracked interface’s link goes down. For example, if the VRRPE interface’s
priority is 200 and a tracked interface with track priority 20 goes down, the software
changes the VRRPE interface’s priority to 180. If another tracked interface goes down, the
software reduces the VRID’s priority again, by the amount of the tracked interface’s track
priority.
The most important difference is that all VRRPE routers are Backups. There is no Owner router.
VRRPE overcomes the limitations in standard VRRP by removing the Owner.
Figure 86 shows an example of a VRRPE configuration.