In Cisco IOS routers that use low latency queuing, which algorithm is used to presort traffic going into the default queue? 

Answer options:

A. first-in, first-out
B. last-in, first-out
C. weighted round robin
D. fair queuing
E. random processing

D

WFQ is a flow-based queuing algorithm used in Quality of Service (QoS) that does two things simultaneously: It schedules interactive traffic to the front of the queue to reduce response time, and it fairly shares the remaining bandwidth between high bandwidth flows. A stream of packets within a single session of a single application is known as flow or conversation. WFQ is a flow-based method that sends packets over the network and ensures packet transmission efficiency which is critical to the interactive traffic. This method automatically stabilizes network congestion between individual packet transmission flows.