Explanation/Reference:
Explanation:
In a fully redundant topology with tuned IGP timers, adding redundant supervisors with Cisco nonstop forwarding (NSF) and stateful switchover (SSO) may cause longer convergence times than single supervisors with tuned IGP timers. NSF attempts to maintain the flow of traffic through a router that has experienced a failure. NSF with SSO is designed to maintain a link-up Layer 3 up state during a routing convergence event. However, because an interaction occurs between the IGP timers and the NSF timers, the tuned IGP timers can cause NSF-aware neighbors to reset the neighbor relationships.