A router routes calls to a network of call centers based on estimated call
in-queue wait times (EWTs). The router periodically polls all call centers
for the EWT and average advance time (AAT) of each queue, and increments
each received EWT by a product of the AAT and the number of calls sent to
that queue during the network delay time. Between polls, each time that an
AAT period expires, its corresponding EWT is decremented by the AAT (but
not below zero). When a call is received for processing by a skill/split,
the router sends it to the skill/split queue that presently has the
shortest EWT, and increments that EWT by the corresponding AAT.
