VRRP - Part 2 Object Tracking Using Metric

R2 and R3 are configured for VRRP on a shared LAN segment. R3 is the master unless its route to 13.0.0.0/24 disappears or its metric increases.

R3
interface FastEthernet0/0
ip address 10.0.0.3 255.255.255.0
duplex half
vrrp 1 ip 10.0.0.254
vrrp 1 priority 101
vrrp 1 authentication text RICH

Here is the route to 13.0.0./24

Router_3#s ip route 13.0.0.1
Routing entry for 13.0.0.0/24
Known via "ospf 1", distance 110, metric 61, type intra area
Last update from 12.0.0.5 on FastEthernet1/0, 00:12:32 ago
Routing Descriptor Blocks:
* 12.0.0.5, from 12.0.0.5, 00:12:32 ago, via FastEthernet1/0
Route metric is 61, traffic share count is 1

Note the OSPF metric is 61. For the purposes of tracking 61 i will mark as an UP metric and anything higher/worse will be considered DOWN.

track 10 ip route 13.0.0.0 255.255.255.0 metric threshold
threshold metric up 61 down 62

I introduce the tracking parameter to VRRP

interface FastEthernet0/0
vrrp 1 track 10

I know check the state of the tracked object

Router_3#s track 10
Track 10
IP route 13.0.0.0 255.255.255.0 metric threshold
Metric threshold is Up (OSPF/61/61)
4 changes, last change 00:16:34
Metric threshold down 62 up 61
First-hop interface is FastEthernet1/0
Tracked by:
VRRP FastEthernet0/0 1


The tracked object is marked UP and R3 remains the master!

Router_3#s vrrp brief
Interface Grp Pri Time Own Pre State Master addr Group addr
Fa0/0 1 101 3605 Y Master 10.0.0.3 10.0.0.254

I now increase the metric of the 13.0.0.0 route by increasing the OSPF cost on neighboring router R5.

R5(config)#int fa1/0
R5(config-if)#ip ospf cost 200

R3 detects the metric has changed and decrements the priority by 10 (default) and the router now becomes the backup.

00:44:58: %VRRP-6-STATECHANGE: Fa0/0 Grp 1 state Master -> Backup
Router_3#s vrrp brief
Interface Grp Pri Time Own Pre State Master addr Group addr
Fa0/0 1 91 3605 Y Backup 10.0.0.2 10.0.0.254

Checking the tracking status again.

Router_3#s track 10
Track 10
IP route 13.0.0.0 255.255.255.0 metric threshold
Metric threshold is Down (OSPF/201/201) 5 changes, last change 00:02:08
Metric threshold down 62 up 61
First-hop interface is FastEthernet1/0
Tracked by:
VRRP FastEthernet0/0 1