IPRateMonitor is a C++ class that defines two private structs:
Record and Table. Figure 5.1 contains the C++ code
that defined these structs.
from_rate and to_rate in Record are used to store packet
rates. EWMA implements an exponentially weighted moving average and is
used to keep track of rates. child contains a pointer to a child or
NULL if no child exists. Besides 256 pointers to Record,
Table contains a pointer to the parent record (parent) and two
pointers (prev and next) that are used to maintain a
doubly-linked list of nodes--their use is explained in
Section 5.3. root points to the
root node.
