Which of the following statements would be the most appropriate when one considers Policy-Based Routing (PBR) for QoS?
A.
PBR can only choose a route other than what is in the routing table.
B.
PBR can change the route provided it first classifies and marks the packet.
C.
PBR can change the route and/or mark the packet using precedence.
D.
PBR can only set the precedence if configured to choose a route other than what is in the routing table.
Explanation:
The primary function of Policy-based Routing (PBR) is to bypass the destination-based forwarding functionality of routers by using a route map to make a forwarding decision based on other information.
One additional feature of Policy Based Routing is the ability to modify IP packets by marking them with IP precedence or QoS group.
Reference: Introduction to IP QoS p.2-5