Jonothan Eaves

Eugene Korneychuk, CCIE No. 43253, is a technical leader on the Security TAC Technical Leadership team at Cisco, where he specializes in Cisco Identity Services Engine (ISE) and broader network access security technologies. With more than 20 years of experience in networking and security, Eugene has worked extensively with enterprise customers to design, deploy, and troubleshoot ISE at scale, resolving some of the most complex escalations across on-premises, hybrid, and cloud environments.

A Cisco Live Hall of Fame speaker, Eugene has delivered numerous well-received sessions on ISE, covering topics such as troubleshooting, cloud deployments, automation, and integration with platforms like Microsoft Entra ID and Intune. Beyond his CCIE, he holds multiple certifications spanning AWS, Microsoft Azure, Terraform, and Cisco DevNet, reflecting his broad expertise across cloud platforms, infrastructure as code, and network automation.

Eugene brings a practitioner's perspective to this book, grounded in real-world TAC experience helping customers navigate the everyday challenges of deploying and maintaining identity-based access control at enterprise scale.

Serhii Kucherenko, CCIE No. 35182, is an Escalations technical leader within the Meraki Customer Support team at Cisco CX, where he specializes in resolving highly complex technical challenges involving Meraki MX SD-WAN solutions. With a background deeply rooted in network security and access control, Serhii spent six years in the Cisco TAC AAA team, where he provided expert support for Cisco Identity Services Engine, TrustSec, and broad network access security architectures.

A subject matter expert in endpoint security, Serhii focuses extensively on the intricacies of endpoint posture assessment. As a long-time Cisco Live speaker, he has delivered numerous sessions on Cisco ISE and Meraki SD-WAN, consistently sharing his deep technical knowledge with the broader community.

Serhii brings a practitioner's perspective to his work, grounded in years of hands-on TAC experience helping customers navigate the everyday complexities of deploying and maintaining secure, scalable network environments.

Jonothan Joff Eaves, CCIE No. 4242, is a technical marketing engineer in the Cisco Campus Networking Group. His specialization is switching security with a focus toward group-based policies, automating network security functions and enabling software-defined segmentation.

Jonothan has presented network segmentation topics many times at Cisco Live, Webinars and Partner conferences, and works with Cisco Engineering teams to develop new features and functions as needed.

Prior to joining that group, Jonothan worked on solution validation covering network access security technologies (including security group mechanisms), voice, WAN, and routing projects and gained CCIE in 1998 (#4242). He has worked in the industry for 37 years, 29 of which have been with Cisco.