What are two functions of the PFE?

The Packet Forwarding Engine (PFE) in Juniper’s routers is primarily responsible for managing the flow of data packets through the device. One of its key functions is to apply the class of service (CoS) functionality. This involves classifying and prioritizing packets based on different policies set by the network administrator, allowing for differentiated traffic handling and ensuring that critical data packets receive appropriate bandwidth and latency treatment. CoS ensures optimal performance for various applications by controlling how packets are treated as they traverse through the network.

While the PFE can play a role in forwarding transit traffic, which is another primary responsibility, the specific choice focuses on the application of CoS, making it a clear function that aligns with the PFE's duties in traffic management and quality of service assurance.