Even medicated, your answers are clearer than many. Prof. Tom Lisa, CCAI Community College of Southern Nevada Cisco ATC/Regional Networking Academy
John Neiberger wrote: > 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=41990&t=41957 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
