Two Backup Routers
In this configuration, Host B could be a gateway router. As such, interface eth1 on Routers R1, R2, and R3, and the gateway router, would run the IGP protocol.
Topology
Figure 1-177: Configuring VRRP with Two Backup Routers
R1
#configure terminal | Enter the Configure mode. |
(config)#interface eth2 | Enter interface mode for eth2. |
(config-if)#ip address 2.2.2.1/24 | Configure the IP address for interface eth2 to be in network 0. |
(config-if)#commit | Commit the candidate configuration to the running configuration. |
(config-if)#exit | Exit interface mode. |
(config)#interface eth1 | Enter interface mode for eth1. |
(config-if)#ip address 1.1.1.1/24 | Configure the IP address for interface eth1 to be in network 1. |
(config-if)#commit | Commit the candidate configuration to the running configuration. |
(config-if)#exit | Exit interface mode. |
(config)#router vrrp 1 eth2 | Create a VRRP instance for interface eth2. |
(config-router)#virtual-ip 2.2.2.1 owner | Configure R1 as the owner. |
(config-router)#advertisement-interval 100 | Configure the default value for the advertisement interval. The configurable range is 5 to 4095 centi seconds (value must be a multiple of 5). |
(config-router)#preempt-mode true | Set true as the default value for the field. |
(config-router)# v2-compatible | Enable the v2-compatible |
(config-router)#authentication text abcd | Configure the authentication text to specify that as simple text for vrrpv2 packets, accept only 8 characters |
(config-router)#enable | Enable the VRRP session on the router. |
(config-router)#commit | Commit the candidate configuration to the running configuration. |
(config-router)#exit | Exit Router mode. |
R2
#configure terminal | Enter the Configure mode. |
(config)#interface eth2 | Enter interface mode for eth2. |
(config-if)#ip address 2.2.2.2/24 | Configure the IP address for interface eth2 to be in network 0. |
(config-if)#commit | Commit the candidate configuration to the running configuration. |
(config-if)#exit | Exit interface mode. |
(config)#interface eth1 | Enter interface mode for eth1. |
(config-if)#ip address 1.1.1.2/24 | Configure the IP address for interface eth1 to be in network 1. |
(config-if)#commit | Commit the candidate configuration to the running configuration. |
(config-if)#exit | Exit interface mode. |
(config)#router vrrp 1 eth2 | Create a VRRP instance for interface eth2. |
(config-router)#virtual-ip 2.2.2.1 | Configure R2 as the backup. |
(config-router)#advertisement-interval 100 | Configure the default value for the advertisement interval. The configurable range is 5 to 4095 centi seconds (value must be a multiple of 5). |
(config-router)#priority 100 | Set the default value for the backup router. |
(config-router)#preempt-mode true | Set true as the default value for the field. |
(config-router)# v2-compatible | Enable the v2-compatible |
(config-router)#authentication text abcd | Configure the authentication text to specify that as simple text for vrrpv2 packets, accept only 8 characters |
(config-router)#enable | Enable the VRRP session on the router. |
(config-router)#commit | Commit the candidate configuration to the running configuration. |
(config-router)#exit | Exit Router mode. |
R3
#configure terminal | Enter the Configure mode. |
(config)#interface eth2 | Enter interface mode for eth2. |
(config-if)#ip address 2.2.2.3/24 | Configure the IP address for interface eth2 to be in network 0. |
(config-if)#commit | Commit the candidate configuration to the running configuration. |
(config-if)#exit | Exit interface mode. |
(config)#interface eth1 | Enter interface mode for eth1. |
(config-if)#ip address 1.1.1.3/24 | Configure the IP address for interface eth1 to be in network 1. |
(config-if)#commit | Commit the candidate configuration to the running configuration. |
(config-if)#exit | Exit interface mode. |
(config)#router vrrp 1 eth2 | Create a VRRP instance for interface eth2. |
(config-router)#virtual-ip 2.2.2.1 | Configure R3 as the backup. |
(config-router)#advertisement-interval 100 | Configure the default value for the advertisement interval. The configurable range is 5 to 4095 centi seconds (value must be a multiple of 5). |
(config-router)#priority 254 | Configure the priority for R3. The configurable range is 1-255. |
(config-router)#preempt-mode true | Set true as the default value for the field. |
(config-router)# v2-compatible | Enable the v2-compatible |
(config-router)#authentication text abcd | Configure the authentication text to specify that as simple text for vrrpv2 packets, accept only 8 characters |
(config-router)#enable | Enable the VRRP session on the router. |
(config-router)#commit | Commit the candidate configuration to the running configuration. |
(config-router)#exit | Exit Router mode. |
Validation
Router 1
R1#show vrrp
VRRP Version: 3
VMAC enabled
Backward Compatibility disabled
Address family IPv4
VRRP Id: 1 on interface: eth2
State: AdminUp - Master
Virtual IP address: 2.2.2.1 (Owner)
Virtual MAC address is 0000.5e00.0101
Operational primary IP address: 2.2.2.1
Operational master IP address: 2.2.2.1
Priority is 255
Advertisement interval: 100 centi sec
Master Advertisement interval: 100 centi sec
Virtual router uptime: 0 hours 9 minutes 6 seconds (54600 centi sec)
Master uptime: 0 hours 1 minutes 18 seconds (7800 centi sec)
Accept mode: TRUE
Preempt mode: TRUE
Auth-type: simple text, String: abcd
Multicast membership on IPv4 interface eth2: JOINED
V2-Compatible: TRUE
Router 2
R2#sh vrrp
VRRP Version: 3
VMAC enabled
Backward Compatibility disabled
Address family IPv4
VRRP Id: 1 on interface: eth2
State: AdminUp - Backup
Virtual IP address: 2.2.2.1 (Not-owner)
Virtual MAC address is 0000.5e00.0101
Operational primary IP address: 2.2.2.2
Operational master IP address: 2.2.2.1
Priority is 100
Advertisement interval: 100 centi sec
Master Advertisement interval: 100 centi sec
Virtual router uptime: 0 hours 11 minutes 28 seconds (68800 centi sec)
Skew time: 80 centi sec
Master Down Interval: 380 centi sec
Accept mode: TRUE
Preempt mode: TRUE
Auth-type: simple text, String: abcd
Multicast membership on IPv4 interface eth2: JOINED
V2-Compatible: TRUE
Router 3
R3#sh vrrp
VRRP Version: 3
VMAC enabled
Backward Compatibility disabled
Address family IPv4
VRRP Id: 1 on interface: eth2
State: AdminUp - Backup
Virtual IP address: 2.2.2.1 (Not-owner)
Virtual MAC address is 0000.5e00.0101
Operational primary IP address: 2.2.2.3
Operational master IP address: 2.2.2.1
Priority is 254
Advertisement interval: 100 centi sec
Master Advertisement interval: 100 centi sec
Virtual router uptime: 0 hours 14 minutes 23 seconds (86300 centi sec)
Skew time: 80 centi sec
Master Down Interval: 380 centi sec
Accept mode: TRUE
Preempt mode: TRUE
Auth-type: simple text, String: abcd
Multicast membership on IPv4 interface eth2: JOINED
V2-Compatible: TRUE
Ping Output at Host A
HOSTA#ping 1.1.1.5
Press CTRL+C to exit
PING 1.1.1.5 (1.1.1.5) 56(84) bytes of data.
64 bytes from 1.1.1.5: icmp_seq=1 ttl=63 time=1.40 ms
64 bytes from 1.1.1.5: icmp_seq=2 ttl=63 time=1.09 ms
Disabling the Master/Owner
#configure terminal | Enter the Configure mode. |
(config)#router vrrp 1 eth2 | Create a VRRP instance for interface eth2. |
(config-router)#disable | Disable the VRRP session. |
(config-router)#commit | Commit the candidate configuration to the running configuration. |
(config-router)#exit | Exit Router mode. |
Output After Disabling the Master
Router 1
R1#sh vrrp
VRRP Version: 3
VMAC enabled
Backward Compatibility disabled
Address family IPv4
VRRP Id: 1 on interface: eth2
State: AdminDown - Init (admin state down)
Virtual IP address: 2.2.2.1 (Owner)
Virtual MAC address is 0000.5e00.0101
Operational primary IP address: 2.2.2.1
Operational master IP address: 2.2.2.1
Priority is 255
Advertisement interval: 100 centi sec
Master Advertisement interval: 100 centi sec
Virtual router uptime: 0 hours 0 minutes 0 seconds (0 centi sec)
Skew time: 80 centi sec
Master Down Interval: 380 centi sec)
Accept mode: TRUE
Preempt mode: TRUE
Auth-type: simple text, String: abcd
Multicast membership on IPv4 interface eth2: LEFT
V2-Compatible: TRUE
Router 3
R3#sh vrrp
VRRP Version: 3
VMAC enabled
Backward Compatibility disabled
Address family IPv4
VRRP Id: 1 on interface: eth2
State: AdminUp - Master
Virtual IP address: 2.2.2.1 (Not-owner)
Virtual MAC address is 0000.5e00.0101
Operational primary IP address: 2.2.2.3
Operational master IP address: 2.2.2.3
Priority is 254
Advertisement interval: 100 centi sec
Master Advertisement interval: 100 centi sec
Virtual router uptime: 0 hours 40 minutes 55 seconds (245500 centi sec)
Master uptime: 0 hours 1 minutes 18 seconds (7800 centi sec)
Accept mode: TRUE
Preempt mode: TRUE
Auth-type: simple text, String: abcd
Multicast membership on IPv4 interface eth2: JOINED
V2-Compatible: TRUE
HOSTA#ping 1.1.1.5
Press CTRL+C to exit
PING 1.1.1.5 (1.1.1.5) 56(84) bytes of data.
64 bytes from 1.1.1.5: icmp_seq=1 ttl=63 time=1.40 ms
64 bytes from 1.1.1.5: icmp_seq=2 ttl=63 time=1.09 m
Last modified date: 08/28/2023