14
V. Liberatore
Pervasive Computing
QoS Assurances
So,
what do we want from QoS?
Worst-case
nReasoning
Reason about system timing
Priorities make it easy
nIs
it cross-traffic?
nIs it failures (e.g., network partition)?
nFailures as first class citizens
Average-case
nNon-sense
nExacerbated
by TCP
Tail
nE.g.,
99-percentile
nMust be paired with middleware, fault-tolerance