@tmarques wrote:
When configuring VRRP parameters between an active and stand-by controller, should Enable Router Pre-emption be checked on on both controllers or just the one that that will have the higher priority value (i.e. the controller that we would want to be the active one at all time)? Should the Delay field be left blank or is there a best practice parameter for that as well?
Regards,
Tony Marques
tmarques,
Please see the Wikipedia entry for VRRP here for answers to all of your questions about VRRP: http://en.wikipedia.org/wiki/Virtual_Router_Redundancy_Protocol
To directly answer your question, you would Enable Router pre-emption on one side of a VRRP if you want a controller that has a higher VRRP priority when it comes up to always take control of a VRRP from a controller with lesser priority. If it is NOT enabled, when a controller is coming up, it will NOT take control of a VRRP when it sees another controller advertising that it is master for that VRRP, even if it has priority.
There is no best design practice for the delay parameter: Accept the default. "This feature prevents unnecessary transitions of VRRP State to MASTER. By adding a delay to the master transition, we prevent a router from becoming the master during network flapping. For a short interval, there may be congestion in the network, or links may be flapping. This should not cause VRRP MASTER to be altered. " It works just fine with the default. A number of administrators have their reasons for editing this parameter, but for most, the default works just fine