I've two 3640 routers (c3640-jk8o3s-mz.122-4.T), connected by 2 serial cables with different bandwidth configured (512K & 64K)
Routing protocol: IGRP. There are LAN's, connected to it's own fa-interfaces on routers:
LAN1---R1===R2---LAN2
For example, variance=100, there are FastSwitching mode on all interfaces
R1# debug ip icmp
R1# ping LAN2-host
& I see, there are per packet destination with ip traffic (FastSwitching )!!!
What's are: IOS bug?
Max