Routing Centralization Across Domains via SDN: A Model and Emulation   Framework for BGP Evolution
  In this work, we propose a radical, incrementally-deployable Internet routing paradigm in which the control plane of multiple networks is centralized. This follows the Software Defined Networking (SDN) paradigm, although at the inter-domain level involving multiple Autonomous Systems (AS). Multi-domain SDN centralization can be realized by outsourcing routing functions to an external contractor, which provides inter-domain routing services facilitated through a multi-AS network controller. The proposed model promises to become a vehicle for evolving BGP and uses the bird's eye view over several networks to benefit aspects of inter-domain routing, such as convergence properties, policy conflict resolution, inter-domain troubleshooting, and collaborative security. In addition to the proposed paradigm, we introduce a publicly available emulation platform built on top of Mininet and the Quagga routing software, for experimenting in hybrid BGP-SDN AS-level networks. As a proof of concept we focus specifically on exploiting multi-domain centralization to improve BGP's slow convergence. We build and make publicly available a first multi-AS controller tailored to this use case and demonstrate experimentally that SDN centralization helps to linearly reduce BGP convergence times and churn rates with expanding SDN deployments. 
Vasileios Kotronis, Adrian Gamperli and Xenofontas Dimitropoulos
cs.NI