BCMSN - Redundancy: VRRP - Explanation & Configuration [CCNP]

VRRP is very similar to HSRP escept it's an open standard and a bit newer.

VRRP & HSRP: Differences

-Active/Standby becomes Master/Backup.
-Standby group becomes VRRP group
-Master router can share Virtual IP . The feature only changes the ip-addr of the Master router (assigns VIP to PR only) whereas the ip for the backup routers (sandby routers) stay the same, the feature is optional and can be used only if you want it that way)
-1 second hello timer (3xhello timer + skew = Down timer.)
-Following is the formula to calculate skew - 256 - 100 (priority) = Ans/256 = 0.x msec is the skew that gets added.

VRRP Configuration:

Step 1 - Configure VRRP Group on the specific physical interface

Step 2 - Optimize settings

Step 3 - Verify

L3Switch#conf t
L3Switch(config)#int fa0/0
L3Switch(config-if)#vrrp 1 ip 172.30.4.90 (1 is the group-no followed by the VIP)
L3Switch(config-if)#vrrp 1 preempt
L3Switch(config-if)#vrrp 1 timers ? (? reveals with 2 options: advertise and learn.)
L3Switch(config-if)#vrrp 1 timers advertise msec 100
L3Switch(config-if)#^z

-In vrrp we don't have to set the dead timer, only just set the hello timer as mentioned earlier. The hold timer is calculated automatically (3xhell time + skew).

-Secondly, the good thing here is that we only have to set the hello timer on the master router (MR), all the other routers are set by default to 'learn' so they'll basically learn their timer based on what the master is using. This is a bonus here compared to HSRP where we have to go on all routers and make sre the timers are set the same on all routers)

Show command for VRRP:

L3Switch#show vrrp