1.1.f Explain UDP operations

  • 1.1.f [i] Starvation
  • 1.1.f [ii] Latency

from:

http://www.chainringcircus.org/congestion-link-efficiency-traffic-policing-and-shaping/

when TCP traffic slows (slow start) to deal with dropped traffic, UDP traffic does not slow, resulting in queues being filled by UDP packets, starving TCP of bandwidth.

from:

Enterprise QoS Solution Reference
Network Design Guide

When TCP flows are combined with UDP flows within a single service-provider class and the class
experiences congestion, TCP flows continually lower their transmission rates, potentially giving up their bandwidth to UDP flows that are oblivious to drops. This effect is called TCP starvation/UDP
dominance.
TCP starvation/UDP dominance likely occurs if (TCP-based) Mission-Critical Data is assigned to the same service-provider class as (UDP-based) Streaming-Video and the class experiences sustained congestion. Even if WRED is enabled on the service-provider class, the same behavior would be observed because WRED (for the most part) manages congestion only on TCP-based flows.