Example for Configuring the Headquarters (Cisco Router) to Manage Branches Using Efficient VPN and Establishing IPSec Tunnels - AR100, AR120, AR150, AR160, AR200, AR1200, AR2200, AR3200, and AR3600 CLI-based Typical Configuration Examples -
Juniper SRX to Cisco ASA Site to Site with source NAT – Marc Zacho
How to Configure Site to Site IPSec VPN Tunnel in Cisco IOS Router - Tech Support
Why Cisco Routers with SoftEther VPN Server is the Best Solution? - SoftEther VPN Project