15.2.9 Configuring Fault Monitoring Interfaces and VRRP Polling

The Switch uses numbered tracks to manage the configured failure monitoring interfaces and VRRP polling. To create a track, use the track configuration command to specify a track number. When a track is configured for a virtual router, the virtual router monitors the failure monitoring interface specified for the numbered track based on the configuration settings. To configure a track for a virtual router, use the vrrp track configuration command.

You can configure either a priority switching track or a priority decrement track for one virtual router.

If you want to configure multiple tracks for one virtual router, only priority decrement can be used as the priority change method.

The priority switching method changes the priority of a virtual router to the specified priority if a failure is detected. If you do not specify a priority or if you specify a priority higher than the priority of a virtual router, the default value (0) is used. When you select the priority switching method, you can configure only one track for one virtual router.

If you specify a priority of 100 for a virtual router and a switch priority of 10 for a failure monitoring interface, as shown in Figure 15-14: Priority switching method, and a failure is detected on the failure monitoring interface, the priority of the virtual router is set to the switch priority of 10.

Figure 15-14: Priority switching method

The priority decrement method reduces the priority of a failed virtual router by the value specified as the priority decrement. If you do not specify a priority, the default value (255) is used. When you select the priority decrement method, you can configure a maximum of 16 tracks for a virtual router.

If the priority of a virtual router is 100 and the priority of a failure monitoring interface is 60, as shown in Figure 15-15: Priority decrement method, and a failure is detected on the failure monitoring interface, the priority of the virtual router is set to 40, which is the original priority 100 minus the priority decrement value 60.

Figure 15-15: Priority decrement method

<Structure of this section>

(1) Configuring track to perform failure monitoring interfaces

Points to note

Specify line-protocol in the track interface configuration command to monitor the status of the specified VLAN interface, port channel interface, and Ethernet interface.

Set the tracks for the VLAN interface, port channel interface, and Ethernet interface to be monitored.

Use the vrrp track configuration command to configure tracks for a virtual router. The tracks contain the object for which failures will be monitored.

An IP address must be assigned to the VLAN interface that will be monitored for failures.

Command examples

(config)# track 20 interface vlan 30 line-protocol

(config)# track 30 interface gigabitethernet 1/0/8 line-protocol

(config)# track 40 interface port-channel 10 line-protocol
- Sets track 20 as the failure monitoring interface for monitoring the status of VLAN 30.
- Sets track 30 as the failure monitoring interface for monitoring the status of Gigabit Ethernet interface 1/0/8.
- Sets track 40 as the failure monitoring interface for monitoring the status of channel group 10.
(config-if)# vrrp 1 track 20 decrement 60

(config-if)# vrrp 1 track 30 decrement 10

(config-if)# vrrp 1 track 40 decrement 40

Enter VLAN configuration mode for the VLAN on which the virtual router has been configured beforehand. In this case, tracks 20, 30, and 40 are configured for virtual router VRID 1.
- If a failure occurs on the failure monitoring interface set for track 20, the priority of the virtual router is decreased by 60.
- If a failure occurs on a failure monitoring interface that is set to a track with track number 30, the virtual router 1 is prioritized 10 lower.
- If a failure occurs on a failure monitoring interface that is set to a track with track number 40, the virtual router 1 is prioritized 40 lower.

(2) Configuring track for VRRP polling

Points to note

Specify ip routing in the track interface configuration command to monitor the specified VLANs and to check reachability of the destinations specified in the track ip route configuration command by pinging them.

Set tracks for the VLAN interfaces for which VRRP is to be used.

Use the vrrp track configuration command to configure tracks for a virtual router. The tracks contain the configuration settings for VRRP polling.

When you use VRRP polling to monitor failures, you need to assign an IP address to the VLAN interface used for VRRP polling and specify the route to the destination specified in the track ip route command.

When you configure the same track for multiple virtual routers, each virtual router sends VRRP polling packets.

Command examples

(config)# track 50 interface vlan 34 ip routing

(config)# track 51 interface vlan 35 ip routing

(config)# track 52 interface vlan 36 ip routing
- Sets track 50 as the sending interface for VRRP polling for monitoring the status of VLAN 34.
- Sets track 51 as the sending interface for VRRP polling for monitoring the status of VLAN 35.
- Sets track 52 as the sending interface for VRRP polling for monitoring the status of VLAN 36.
(config)# track 50 ip route 192.168.20.1 reachability

(config)# track 51 ip route 192.168.21.1 reachability

(config)# track 52 ip route 192.168.22.1 reachability
- For track 50, 192.168.20.1 is set as the VRRP polling destination.
- For track 51, 192.168.21.1 is set as the VRRP polling destination.
- For track 52, 192.168.22.1 is set as the VRRP polling destination.
(config-if)# vrrp 3 track 50 priority 10

(config-if)# vrrp 4 track 51 decrement 20

(config-if)# vrrp 4 track 52 decrement 50
- Enter VLAN configuration mode for the VLAN on which the virtual router has been configured beforehand.
- The first command configures track 50 for virtual router VRID 3, sets priority switching as the priority change method, and sets 10 as the alternate priority. If a failure is detected by the VRRP polling defined for track 50, the priority of the virtual router is changed to 10.
- The second and third commands configure tracks 51 and 52 for virtual router VRID 4 and set the priority change method to priority decrement. Sets 20 as the priority subtraction of track number 51. The third command sets 50 as the priority decrement value for track 52. If VRRP polling configured for track with track number 51 fails, virtual router 4 is prioritized 20 lower. If a failure is detected by the VRRP polling defined for track 52, the priority of the virtual router is decreased by 50. If failures occur on both failure monitoring interfaces defined for tracks 51 and 52, the priority of the virtual router is decreased by 70.