Unicast Reverse Path Forwarding
Question 1
What is the goal of Unicast Reverse Path Forwarding?
A. to verify the reachability of the destination address in forwarded packets
B. to help control network congestion
C. to verify the reachability of the destination address in multicast packets
D. to verify the reachability of the source address in forwarded packets
Answer: D
Question 2
Which implementation can cause packet loss when the network includes asymmetric routing paths?
A. the use of ECMP routing
B. the use of penultimate hop popping
C. the use of Unicast RPF
D. disabling Cisco Express Forwarding
Answer: C
When administrators use Unicast RPF in strict mode, the packet must be received on the interface that the router would use to forward the return packet. Unicast RPF configured in strict mode may drop legitimate traffic that is received on an interface that was not the router’s choice for sending return traffic. Dropping this legitimate traffic could occur when asymmetric routing paths are present in the network.
Here the source:
http://www.cisco.com/web/about/security/intelligence/unicast-rpf.html