Understanding Data Center Traffic Characteristics

As data centers become more and more central in Internet
communications, both research and operations communities
have begun to explore how to better design and manage
them. In this paper, we present a preliminary empirical
study of end-to-end traffic patterns in data center networks
that can inform and help evaluate research and operational
approaches. We analyze SNMP logs collected at 19 data cen-
ters to examine temporal and spatial variations in link loads
and losses. We find that while links in the core are heavily
utilized the ones closer to the edge observe a greater degree
of loss. We then study packet traces collected at a small
number of switches in one data center and find evidence of
ON-OFF traffic behavior. Finally, we develop a framework
that derives ON-OFF traffic parameters for data center traf-
fic sources that best explain the SNMP data collected for the
data center. We show that the framework can be used to
evaluate data center traffic engineering approaches. We are
also applying the framework to design network-level traffic
generators for data centers.