Question

In RPF, a router forwards only the copy that has traveled the _______ path from the source to the router.

a) Shortest
b) Longest
c) Most efficient
d) Reverse

Answer 1

In RPF, a router forwards the copy of a packet that has traveled the shortest path from the source to the router, as part of an anti-looping and efficiency mechanism in multicast routing.

Step-by-step explanation:

In RPF (Reverse Path Forwarding), a router forwards only the copy that has traveled the shortest path from the source to the router. RPF is a technique used to prevent loop formation and ensure that multicast traffic is forwarded efficiently. When a router receives a multicast packet, it checks the packet against the router's current routing table to verify that it arrived on the interface that provides the shortest path back to the source of the packet. If the packet arrived on the shortest path interface, the RPF check passes and the packet is considered for further forwarding. Otherwise, it is dropped to prevent loops and duplicate packets within the network.