Connectivity Guide

The example shows a typical network conguration using VRRP. Instead of conguring the hosts on network 10.10.10.0 with the IP address
of either Router A or Router B as the default router, the default router of all hosts is set to the IP address of the virtual router. When any
host on the LAN segment requests Internet access, it sends packets to the IP address of the virtual router.
Router A is congured as the master router with the virtual router IP address and sends any packets addressed to the virtual router to the
Internet. Router B is the backup router and is also congured with the virtual router IP address.
If Router A, the master router, becomes unavailable (the connection between the LAN segment and Router A on ethernet 1/1/6 goes
down), Router B, the backup router, automatically becomes the master router and responds to packets sent to the virtual IP address. All
workstations continue to use the IP address of the virtual router to transmit packets destined to the Internet. Router B receives and
forwards packets on interface ethernet 1/1/5. Until Router A resumes operation, VRRP allows Router B to provide uninterrupted
service to the users on the LAN segment accessing the Internet.
When the interface that Router A uses to provide gateway services (ethernet 1/1/7) goes down, Router B does not take over automatically.
For Router B to become the master router, you must congure interface tracking. When you congure tracking on the interface and the
interface goes down, the VRRP group's priority decreases. The lowered priority of the VRRP group triggers an election and Router B
becomes the master router. See Interface/object tracking for more information.
Create virtual router
VRRP uses the VRID to identify each virtual router congured. Before using VRRP, you must congure the interface with the primary IP
address and enable it.
• Create a virtual router for the interface with the VRRP identier in INTERFACE mode, from 1 to 255.
vrrp-group vrrp-id
• Delete a VRRP group in INTERFACE mode.
no vrrp-group vrrp-id
Congure VRRP
OS10(config)# interface ethernet 1/1/5
OS10(conf-if-eth1/1/5)# vrrp-group 254
Verify VRRP
OS10(conf-eth1/1/5-vrid-254)# do show running-configuration
...
!
interface ethernet 1/1/5
ip address 10.10.10.1/24
!
vrrp-group 254
no shutdown
...
Group version
Congure a VRRP version for the system. Dene either VRRPv2 — vrrp version 2 or VRRPv3 — vrrp version 3.
• Congure the VRRP version for IPv4 in INTERFACE mode.
vrrp version
Congure VRRP version 3
OS10(config)# vrrp version 3
1 Set the switch with the lowest priority to vrrp version 2.
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Layer 3