I can't remember the exact terminology but an IGRP router is aware of a neighbors metric to a destination as well as its own metric to the same destination. The router will only consider routes to be valid if the upstream router's metric to the destination is lower than its own metric to the same destination. This prevents the problems you mentioned below. You may want to get a second opinion on this!
Tim ""nwo"" wrote in message news:[EMAIL PROTECTED] > It occurs to me that I do not understand how IGRP unequal load balancing > works. > > Yes, I understand what the commands are, and I am well aware of the > intricacies involved in fast-switching and CEF. So please don't respond by > telling me to configure 'variance' or stuff like that. I already know all > that. > > What I don't understand is this. A fundamental part of EIGRP unequal load > balancing is the concept of the feasible successor, where routes of unequal > metric to a particular destination will be considered only if the > corresponding neighbor is a feasible successor for the destination in > question. This is in order to prevent the problem of packets being sent to > to a router that is actually further away from the destination than the > sending router is to that destination. > > Yet, I am aware of no such safeguards in IGRP. IGRP has no such concept of > a topology table with neighbor's advertised distances and whatnot. > Therefore it seems that packets could easily be forwarded away from the > destination. Furthermore, it would seem to me that packets could actually > bounce back and forth between 2 routers for awhile. > > Please say it ain't so. Yet I am unaware of any construct within IGRP that > would prevent it from being so. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=66667&t=66667 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
