1.1.f Explain UDP operations

1.1.f [i] Starvation

When TCP flows are combined with UDP flows within a single class and the class experiences congestion, TCP flows continually lower their transmission rates due to congestion control, potentially giving up their bandwidth to UDP flows that are oblivious to drops. This effect is called TCP starvation or UDP dominance.

Even if WRED is enabled on the class, the same behavior would be observed because WRED (for the most part) manages congestion only on TCP-based flows.

Adam, Paul (2014-07-12). All-in-One CCIE V5 Written Exam Guide (Kindle Locations 1169-1172).  . Kindle Edition.

http://www.cisco.com/c/en/us/td/docs/solutions/Enterprise/WAN_and_MAN/QoS_SRND/QoS-SRND-Book/VPNQoS.html