The key words here are Feasible Distance and Advertised Distance, or in this case, reported distance. The FD is the metric for the current path. If we have two neighbors who are reporting that they can reach that network, both will be advertising what *their* FD is, which from our perspective is the Advertised Distance.
[RA]-------(10)--------[RB]-----(50)-----Network Z \ / \ / \------(20)--------[RC]-----(50)------/ Imagine that somewhere beyond Routers B and C is a Network, Z. They each have a metric of 50 to that network, which is their FD. Router A will see two available routes to Z but the one through B has a lower metric and it will be installed into the routing table. However, because RC's Advertised Distance to Z (50) is less than Router A's current FD (60), it will be installed as a feasible successor. If the metric from Router C to Network Z was 60 or over, it would not be a feasible successor. In that case, if the link from A to B were to go away, A would not immediately begin using RC as the next hop to Z. Instead it would send queries to all of its EIGRP neighbors and it would start forwarding to C after C answers that it can reach Z. I hope that makes sense. I have a cold and am fairly medicated right now. ;-) John >>> "Sean Wolfe" 4/19/02 9:34:03 AM >>> EIGRP question: According to Cisco's website: "Feasible distance is the best metric along a path to a destination network, including the metric to the neighbor advertising that path. A feasible successor is a path whose reported distance is less than the feasible distance." But wouldn't a route with a distance less than the feasible distance be in the routing table already, since it had a better metric? It makes more sense to me that the feasible successor is a route with a slightly larger metric than the current route. That way if the current route dies, the next-best path is promoted. But that's not what I'm reading at http://www.cisco.com/warp/public/103/eigrp1.html#6 So . . . whaddya say? Thanks, -Sean. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=41970&t=41957 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]