Section 2.2: EIGRP
Q: Can I just use passive interfaces to reduce the CPU processing?
A: Passive interfaces with no requirements for adjacencies will reduce CPU processes, but a superior way to enable this within EIGRP exists.
Q: If I use the neighbor command, won't that be sufficient as I will no longer be multicasting my EIGRP "hellos"?
A: This will not be sufficient.
Q: I have modified my hello timer on R8 and now my routes are flapping. Is this acceptable?
A: No, you need to remember that R8 will have formed a neighbor relationship on VLAN2; you should ensure that all routers are configured in the same manner.
Q: I have configured R6 and R8 with identical hello intervals but I find that my routes are still flapping. Is this acceptable?
A: No, you should maintain a reliable neighbor relationship with R4; consider adjusting other EIGRP parameters.