Hi, Studying EIGRP, I got to a question: When is the Feasible Distance (FD) for a destination updated. In Jeff Doyles Routing TCP/IP, chapter 8, it says that as a result of a local computation the following may occur:
-If the feasible successor with the lowest distance is different from the existing successor, the feasible successor will become the successor. -If the new distance is lower than the FD, the FD will be updated. -If the new distance is different from the existing distance, updates will be sent to all neighbors. So I asume that as a result of a local computation the FD may be updated (reduced). Later in this chapter, before figure 8.15 it says: Because the distance to 10.1.7.0 has increased and the route did not become active, the FD is unchanged at Lilienthal. In EIGRP's White Paper on cisco's web site, after figure 3 it says: When the link between Routers One and Three goes down, Router One examines each path it knows to Network A and finds that it has a feasible successor through Router Four. Router One uses this route, using the metric through Router Four as the new feasible distance. In the book , Network Design and Case Studies by Cisco , Chapter 3 Designing Large Scale Ip netwoks, Subtitle : Enhanced EIGRP Convergence , It is mentioned that the FD can only change during an active-to-passive transition . I am totally confused about the FD and what triggers an update for it. I don't get it. Is a ROUTE ACTIVATION required for a FD update necessarily? If the router receives a better advertisement , and if the FD is lower , I feel FD can change during a local computation itself . Could any one explain? Thanks in advance, Hamid __________________________________________________ Do You Yahoo!? Yahoo! Greetings - send holiday greetings for Easter, Passover http://greetings.yahoo.com/ Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=39953&t=39953 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
