The encryption suite underneath almost every Cisco VPN. Articles tagged IPsec cover IKEv2 negotiation, transform sets, SA lifetimes, and reading a phase 1 or phase 2 failure.
What an SA is, why IKE runs in two phases, and which bytes of your packet actually get encrypted. Grounded in real packet captures on the transit link between two Cisco IOS XE edge routers in a CML lab.
Complete site-to-site IPsec VPN build with crypto maps on IOS XE: ISAKMP policy, keys, transform set, interesting traffic, and the crypto map itself, with every line of CLI output captured from live cat8000v routers in CML.