AES-GCM (Galois/Counter Mode)encryption is recommended for VPNs because it provides strong encryption with high performance and low overhead, making it an ideal choice for environments where both endpoints support it. AES-GCM combines encryption and authentication in a single step, resulting in faster processing compared to traditional encryption modes that handle these tasks separately. This mode is advantageous for maintaining high throughput in VPN tunnels, especially beneficial for branch office or inter- site VPNs where performance is critical.