VRRP, HSRP, and the Master Router

Brian Scheibe VRRP selects a Master (Active), router in the same manner as HSRP.
It all depends. Does preempt enable and are priority settings made on routers in VRRP group? Which router has the most IP addresses? Which router has the VRRP group’s IP address? All of these factors are important when determining which device will be the Master VRRP router.
One of the differences between VRRP & HSRP is that preempt can be enabled by default in VRRP. This logic would suggest that Router1 would be the master router if Router1 was configured with the highest configurable priority value of 254. This is not always true. Here are some rules:
* The maximum VRRP priority is 255.
According to the rules above, configure Router2’s VLAN 1 IP address (the interface on the VRRP groups is configured) to the VRRP Group. Router2, and not Router1, will always act as the master router when Router2 becomes functional and preempt is enabled.
We also know that Router2 is always the master router, so we need to consider what happens if Router2 goes down, and it is brought back up. It becomes the master router once again. This is not always the case with HSRP. The default preempt setting for HSRP cannot be disabled. Preempt must be enabled in order for the former HSRP master to resume the master role.
There are many reasons why you might want to know the details of how the master VRRP router was chosen. Consider how long it takes for your network to converge. You should also consider the time it will take for the router’s to learn routes. The router will drop packets from destinations not listed in its routing table while it is learning. This will allow you to set the VRRP delay to allow the router to learn routes before it assumes the master role. Another reason could be that you want the fastest or most reliable router to be the master.
While VRRP and HSRP offer redundancy, it’s not safe to assume they will choose the same master.

References:IETF RFC 5798http://tools.ietf.org/html/rfc5798
Cisco: Virtual Router Redundancy Protocol: Feature Overview: VRRP Router Priorityhttp://www.cisco.com/en/US/docs/ios/12_0st/12_0st18/feature/guide/st_vrrpx.html#wp1035078

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