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V. Liberatore
Pervasive Computing
Quality-of-Service (QoS)
*Best-effort model
nPrevalent in the Internet
nNo end-to-end circuit
nPackets can be delayed
nDelay is often unpredictable
nNo bandwidth reservation
*QoS
nAmeliorate best-effort model
nE.g., packet priorities
*Impact on control
nDelays
*E.g., forces small feedback gains
nPacket drop-outs
*Infinite delays
nJitter
*Delay variability
*Often more critical than average delays
nBandwidth
*Relevance?
*