Netgear XCM8810 - 8800 SERIES 10-SLOT CHASSIS SWITCH ユーザーズマニュアル
Chapter 19. VRRP
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NETGEAR 8800 User Manual
VRRP Master Preemption
VRRP master preemption is a feature that allows a VRRP router with a higher VRRP priority
to take control from a lower priority master. VRRP election occurs at network startup or when
the master becomes unavailable. VRRP preemption occurs when a new VRRP router is
added to the network or recovers, and that router has a higher priority than the current VRRP
master.
to take control from a lower priority master. VRRP election occurs at network startup or when
the master becomes unavailable. VRRP preemption occurs when a new VRRP router is
added to the network or recovers, and that router has a higher priority than the current VRRP
master.
Note:
The router that owns the virtual IP address always preempts,
independent of the VRRP preemption setting.
When a VRRP enabled router preempts the master, it does so in one of the following ways:
•
If the preempt delay timer is configured for between 1 and 3600 seconds and the
lower-priority master is still operating, the router preempts the master when the timer
expires.
expires.
•
If the preempt delay timer is configured for 0, the router preempts the master after 3 times
the hello interval.
•
If the higher priority router stops receiving advertisements from the current master for 3
times the hello interval, it takes over mastership immediately.
The preempt delay timer provides time for a recovering router to complete start up before
preempting a lower-priority router. If the preempt delay timer is configured too low, traffic is
lost between the time the preempting router takes control and the time when it has completed
startup.
preempting a lower-priority router. If the preempt delay timer is configured too low, traffic is
lost between the time the preempting router takes control and the time when it has completed
startup.
To enable VRRP master preemption and configure the preempt delay timer, use the following
command:
command:
configure vrrp vlan <vlan_name> vrid <vridval> preempt {delay <seconds>}
To disable VRRP master preemption, use the following command:
configure vrrp vlan <vlan_name> vrid <vridval> dont-preempt
VRRP Guidelines
The following guidelines apply to using VRRP:
•
VRRP packets are encapsulated IP packets.
•
The VRRP multicast address is 224.0.0.18.
•
The virtual router MAC address is
00 00 5E 00 01 <vrid>
•
Duplicate VRIDs are allowed on the router but not on the same IP interface or VLAN.
•
The maximum number of supported VRIDs per interface is seven.
•
An interconnect link between VRRP routers should not be used, except when VRRP
routers have hosts directly attached.