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Command Attributes (VRRP Group Configuration Detail)
• Associated IP Table – IP interfaces associated with this virtual router group.
• Associated IP – IP address of the virtual router, or secondary IP addresses
assigned to the current VLAN interface that are supported by this VRRP group. If
this address matches a real interface on this switch, then this interface will become
the virtual master router for this VRRP group.
• Advertisement Interval – Interval at which the master virtual router sends
advertisements communicating its state as the master. (Range: 1-255 seconds;
Default: 1 second)
- VRRP advertisements from the current master virtual router include information
about its priority and current state as the master.
- VRRP advertisements are sent to the multicast address 224.0.0.8. Using a
multicast address reduces the amount of traffic that has to be processed by
network devices that are not part of the designated VRRP group.
- If the master router stops sending advertisements, backup routers will bid to
become the master router based on priority. The dead interval before attempting
to take over as the master is three times the hello interval plus half a second.
• Preempt Mode – Allows a backup router to take over as the master virtual router
if it has a higher priority than the acting master virtual router (i.e., another backup
router that has taken over from the VRRP group address owner.) (Default: Enabled)
• Preempt Delay – Time to wait before issuing a claim to become the master.
(Range: 0-120 seconds; 0 seconds)
• Priority – The priority of this router in a VRRP group. (Range: 1-254; Default: 100)
- The priority for the VRRP group address owner is automatically set to 255.
- The priority for backup routers is used to determine which router will take over
as the acting master router if the current master fails.
• Authentication Type – Authentication mode used to verify VRRP packets
received from other routers. (Options: None, Simple Text)
- If simple text authentication is selected, then you must also enter an
authentication string.
- All routers in the same VRRP group must be set to the same authentication
mode, and be configured with the same authentication string.
- Plain text authentication does not provide any real security. It is supported only
to prevent a misconfigured router from participating in VRRP.
• Authentication String – Key used to authenticate VRRP packets received from
other routers. (Range: 1-8 alphanumeric characters)
- When a VRRP packet is received from another router in the group, its
authentication string is compared to the string configured on this router. If the
strings match, the message is accepted. Otherwise, the packet is discarded.
Configuring Router Redundancy
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