IPsec

FlexVPN and DMVPN are the two VPN frameworks that define Cisco’s site-to-site and remote access tunnel architectures — and the CCIE Security v6.1 lab tests both extensively. FlexVPN, built on IKEv2 (RFC 7296), unifies site-to-site, hub-and-spoke, and remote access VPN under a single CLI framework with smart defaults that cut configuration by 60-70%. DMVPN, the mGRE + NHRP + IPsec overlay that has dominated enterprise branch networking since IOS 12.4, still powers over 70% of production branch VPN deployments according to Cisco’s enterprise networking data. ...

A Cisco Catalyst 8000V running on a $1/day AWS t3.medium instance gives you a production-grade hybrid cloud lab that connects to your on-prem CML or EVE-NG environment via IPsec VPN with BGP. This is the fastest way for a network engineer to get hands-on with cloud networking using real infrastructure instead of slides and diagrams. Key Takeaway: Building a hybrid cloud lab with AWS VPC and Cisco Catalyst 8000V costs under $2/day, teaches cloud networking fundamentals through a network engineer’s lens, and maps directly to CCIE EI v1.1 blueprint topics — making it the single best investment for bridging traditional and cloud networking skills. ...