Connectivity Guide
The example shows a typical network conguration using VRRP. Instead of conguring 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 congured 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 congured 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 congure interface tracking. When you congure 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 congured. Before using VRRP, you must congure the interface with the primary IP
address and enable it.
• Create a virtual router for the interface with the VRRP identier in INTERFACE mode, from 1 to 255.
vrrp-group vrrp-id
• Delete a VRRP group in INTERFACE mode.
no vrrp-group vrrp-id
Congure 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
Congure a VRRP version for the system. Dene either VRRPv2 — vrrp version 2 or VRRPv3 — vrrp version 3.
• Congure the VRRP version for IPv4 in INTERFACE mode.
vrrp version
Congure VRRP version 3
OS10(config)# vrrp version 3
1 Set the switch with the lowest priority to vrrp version 2.
604
Layer 3