Although many studies have been done on power man-
agement techniques for the networking infrastructure, there
has not been much prior work focusing on saving data trans-
fer energy at the end systems (sender and receiver nodes).
There has been studies on Energy Ecient Ethernet [3] for
making ethernet cards more energy ecient, but these were
very limited in the scope since they were only considering the
energy saving of the ethernet card and not the entire end-
system (including the CPU, memory, disk etc). Prior stud-
ies [4,28,34] show that at least one quarter of the data trans-
fer power consumption happens at the end-systems (sender
and receiver nodes) and the rest at the networking infras-
tructure. Signicant amount of data transfer energy savings
can be obtained at the end-systems with no or minimal per-
formance penalty. Although network-only approaches are
important part of the solution, the end-system power man-
agement is another key in optimizing energy eciency of the
data transfers, which should not be ignored.