- Hot Standby Routing Protocol
- Virtual Router Redundancy Protocol
- Gateway Load Balancing Protocol
- Configuration Example: HSRP
- Configuration Example: GLBP
Virtual Router Redundancy Protocol
VRRP is an election protocol that dynamically assigns responsibility for one or more virtual routers to the VRRP routers on a LAN, allowing several routers on a multiaccess link to use the same virtual IP address. A VRRP router is configured to run VRRP in conjunction with one or more other routers attached.
Configuring VRRP
Router(config)# interface fastethernet 0/0 |
Moves to interface config mode |
Router(config-if)# ip address 172.16.100.5 255.255.255.0 |
Assigns IP address and netmask |
Router(config-if)# vrrp 10 ip 172.16.100.1 |
Enables VRRP for group 10 on this interface with a virtual address of 172.16.100.1. The group number can be from 1 to 255. |
Router(config-if)# vrrp 10 description Engineering Group |
Assigns a text description to the group |
Router(config-if)# vrrp 10 priority 110 |
Sets the priority level for this router. The range is from 1 to 254. The default is 100. |
Router(config-if)# vrrp 10 preempt |
This router will preempt, or take over, as the virtual router master for group 10 if it has a higher priority than the current virtual router master |
Router(config-if)# vrrp 10 preempt delay minimum 60 |
This router will preempt, but only after a delay of 60 seconds |
Router(config-if)# vrrp 10 timers advertise 15 |
Configures the interval between successful advertisements by the virtual router master |
Router(config-if)# vrrp 10 timers learn |
Configures the router, when acting as a virtual router backup, to learn the advertisement interval used by the virtual router master |
Router(config-if)# vrrp 10 shutdown |
Disables VRRP on the interface, but configuration is still retained |
Router(config-if)# no vrrp 10 shutdown |
Reenables the VRRP group using the previous configuration |
Verifying VRRP
Router# show running-config |
Displays contents of dynamic RAM |
Router# show vrrp |
Displays VRRP information |
Router# show vrrp brief |
Displays a brief status of all VRRP groups |
Router# show vrrp 10 |
Displays detailed information about VRRP group 10 |
Router# show vrrp interface fastethernet 0/0 |
Displays information about VRRP as enabled on interface fastethernet 0/0 |
Router# show vrrp interface fastethernet 0/0 brief |
Displays a brief summary about VRRP on interface fastethernet 0/0 |
Debugging VRRP
Router# debug vrrp all |
Displays all VRRP messages |
Router# debug vrrp error |
Displays all VRRP error messages |
Router# debug vrrp events |
Displays all VRRP event messages |
Router# debug vrrp packets |
Displays messages about packets sent and received |
Router# debug vrrp state |
Displays messages about state transitions |