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
Which implementation can cause packet loss when the network includes asymmetric routing paths?
Which implementation can cause packet loss when the network includes asymmetric routing paths?
Unicast RPF (Reverse Path Forwarding) is used to verify that the ‘Sender’ or ‘Source Address’ of the packet being inspected by uRPF is reachable according to the OUTGOING interface the RIB contains for the host’s source address. For example, if a packet comes in interface Fa0/1 from IP 192.168.1.1, but the route to the SOURCE address of that packet points to 192.168.1.0/24 out Fa0/0, the packet will fail the uRPF check.
uRPF strict mode will drop packets if there is asymmetric routing.
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
http://www.cisco.com/c/en/us/about/security-center/unicast-reverse-path-forwarding.html
strict mode – drop the asymmetric routing