Author and instructor Blog Posts: 4 David Bombal is an author and instructor at GNS3 and O'Reilly Media. He creates worldwide instructor-led and self-paced video training on new and emerging technologies such as SDN. He's involved in multiple SDN and OpenFlow projects which include both open source as well as commercial SDN controllers. His YouTube channel has more than 1 million views. Bombal holds numerous certifications, including CCIE #11023 (Emeritus). He's designed, implemented and managed networks ranging from single sites to those that span 50 countries.