IKEv2 IPsec virtual private networks : understanding and deploying IKEv2, IPsec VPNs, and FlexVPN in Cisco IOS
Bartlett, Graham

The IKEv2 protocol significantly improves VPN security, and Cisco’s FlexVPN offers a unified paradigm and command line interface for taking full advantage of it. Simple and modular, FlexVPN relies extensively on tunnel interfaces while maximizing compatibility with legacy VPNs. Now, two Cisco network security experts offer a complete, easy-tounderstand, and practical introduction to IKEv2, modern IPsec VPNs, and FlexVPN.