``There is More to IXPs than Meets the Eye"
Nikolaos Chatzis, Georgios Smaragdakis, Anja Feldmann, and Walter Willinger.
ACM SIGCOMM Computer Communication Review, 45(5), October 2013.
Internet eXchange Points (IXPs) are generally considered to be the successors
of the four Network Access Points (NAPs) that were mandated as part of the
decommissioning of the National Science Foundation Network (NSFNET) in 1994/95
to facilitate the transition from the NSFNET to the ``public Internet" as we
know it today. While this popular view does not tell the whole story behind the
early beginnings of IXPs, what is true is that since around 1994, the number of
operational IXPs worldwide has grown to more than 300 (as of May 2013), with
the largest IXPs handling daily traffic volumes comparable to those carried by
the largest Tier-1 ISPs. However, IXPs have never really attracted much
attention from the networking research community. At first glance, this lack of
interest seems understandable as IXPs have apparently little to do with current
``hot" topic areas such as data centers and cloud services or Software Defined
Networking (SDN) and mobile communication. However, we argue in this article
that, in fact, IXPs are all about data centers and cloud services and even SDN
and mobile communication and should be of great interest to networking
researchers interested in understanding the current and future Internet
ecosystem. To this end, we survey the existing but largely fragmented sources
of publicly available information about IXPs to describe their basic technical
and operational aspects and highlight the critical differences among the
various IXPs in the different regions of the world, especially in Europe and
North America. More importantly, we illustrate the important role that IXPs
play in today's Internet ecosystem and discuss how IXP-driven innovation in
Europe is shaping and redefining the Internet marketplace, not only in Europe
but increasingly so around the world.