While testing out a VRRP solution, I noticed that it was not performing as expected. The VRRP address was unresponsive so I started to investigate. Turning on console logging, I saw a large amount of flapping between Backup and Master states.
... *Mar 1 02:37:23.739: VRRP: Grp 1 Event - Master down timer expired *Mar 1 02:37:23.739: %VRRP-6-STATECHANGE: Vl20 Grp 1 state Backup -> Master *Mar 1 02:37:25.095: %VRRP-6-STATECHANGE: Vl20 Grp 1 state Master -> Backup ...
It turns out that running 8 routers in GNS3 on my laptop was slightly under-powered platform and resulting in over a 2 second maximum response time from a VRRP peer.
Sending 8000, 100-byte ICMP Echos to 10.10.20.1, timeout is 2 seconds: !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!..!!!.......................... ......................................................!!!!!!!!!!!!!!!! !!.................................................................... .....................!!!......................!!!!!!!!!!!.!!!!!!!!!!!! ..!!!!!!!!!!!!!!!!!!!.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!.!!!!!!!!!!!!.!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!.!!!!.!!!!!!!!!!.!!!!!!!!!!.!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!.!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!. Success rate is 74 percent (611/818), round-trip min/avg/max = 4/705/1996 ms Server-A#
After adjusting the advertise timers, everything started to perform as expected.
R1# interface Vlan20 ip address 10.10.20.2 255.255.255.0 vrrp 1 ip 10.10.20.1 vrrp 1 timers advertise 10 vrrp 1 priority 110 R2# interface Vlan20 ip address 10.10.20.3 255.255.255.0 vrrp 1 ip 10.10.20.1 vrrp 1 timers advertise 10