I have reviewed this document as part of the security directorate's ongoing effort to review all IETF documents being processed by the IESG. These comments were written primarily for the benefit of the security area directors. Document editors and WG chairs should treat these comments just like any other last call comments. This document is an incremental change to a layer 2 virtualization layer (Software Defined Networking). As such it properly references RFC5085 for security considerations. That said, I am a bit surprised at the security considerations in RFC5085 which points out that denial of service is an issue but not the introduction of a new set of opportunities for interception. This is surprising given that BGP interception had already been used in international hostilities when the RFC was published. Further the proposed solution is to sprinkle on some magic IPSEC dust or equivalent. While that might be an appropriate approach in an experimental protocol, it is hardly adequate for a production protocol with implications for Internet security as a whole. Given the critical function of this layer and the date of its inception, I would expect to see a comprehensive security architecture developed as part of the overall scheme.