A coin-operated software-defined exchange

Internet Exchange Points (IXPs) play a major role in the current Internet architecture, serving as the connection point between Internet Service Providers (ISPs). Software-Defined Exchange Points (SDXs)-programmable versions of Internet Exchange Points (IXPs)-have been proposed as a way to give ISPs finer-grained control over the way packets are routed between ISPs. Leveraging software-defined networking (SDN) technology, an SDX enables control software to insert forwarding rules that route traffic on the granularity of individual flows. In this paper, we describe work-in-progress developing controllers for Software-Defined Internet Exchange Points that facilitate dynamic establishment of forwarding relationships between transit ISPs. The core hypothesis of our work is that the SDX can serve as a trusted intermediary, both facilitating establishment of dynamic peering agreements between ISPs, and enforcing their routing policies. Moreover, this building block, which we dub the Coin-Operated SDX, can be used to construct much more dynamic and fine-grained end-to-end routing services than are possible in today's infrastructure. In our model, each ISP independently but cooperatively defines the policies that the SDX enforces on its behalf. The SDX may also serve as a clearinghouse for the inter-ISP economic transactions that drive these policies, i.e., as Economic SDX (ESDX). We describe the overall architecture of a Coin-Op SDX, as well as the specific operations it must support to offer dynamic services. We believe that Coin-Op SDX can play a critical role in future software-defined inter-domain Internet infrastructure.