Traditional approaches to remote network state visibility rely
heavily on polling. ?With polling, data is periodically explicitly
retrieved by a client from a server to stay up-to-date.
There are various issues associated with polling-based management:
o ?It introduces additional load on network, devices, and
applications. ?Each polling cycle requires a separate yet arguably
redundant request that results in an interrupt, requires parsing,
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o ?It lacks robustness. ?Polling cycles may be missed, requests may
be delayed or get lost, often particularly in cases when the
network is under stress and hence exactly when the need for the
data is the greatest.
o ?Data may be difficult to calibrate and compare. ?Polling requests
may undergo slight fluctuations, resulting in intervals of
different lengths which makes data hard to compare. ?Likewise,
pollers may have difficulty issuing requests that reach all
devices at the same time, resulting in offset polling intervals
which again make data hard to compare.