Advanced IP Network Design (CCIE Professional Development)

Case Study: Troubleshooting Stuck-in-Active Routes

Stuck-in-active (SIA) routes can be some of the most challenging problems to resolve in an EIGRP network. For more detail on EIGRP's active process, refer to Appendix C. In summary, a route becomes active when it goes down or its metric worsens, and there aren't any feasible successors. When a route goes active on a router, that router sends out queries to all of its neighbors (except through the interface where the route was lost) and awaits the replies. A 3-minute timer starts when the router marks the route as active; if the timer expires without getting all of the replies, the route that was active is considered stuck in active processing (thus the label "stuck-in-active" routes) and requires ...