Hi: Given SDN has been a buzzword within NZNOG, I would recommend RFC 7149 as reading for those interested: http://www.rfc-editor.org/rfc/rfc7149.txt SDN: A perspective from within a Service Provider Environment Cheers -- Sebastian Castro Technical Research Manager .nz Registry Services (New Zealand Domain Name Registry Limited) desk: +64 4 495 2337 mobile: +64 21 400535