Explanation
Smart Tunnel is an advanced feature of Clientless SSL VPN that provides seamless and highly secure remote
access for native client-server applications.
Clientless SSL VPN with Smart Tunnel is the preferred solution for allowing access from non-corporate assets
as it does not require the administrative rights.
Port forwarding is the legacy technology for supporting TCP based applications over a Clientless SSL VPN
connection. Unlike port forwarding, Smart Tunnel simplifies the user experience by not requiring the user
connection of the local application to the local port.
Source:
http://www.cisco.com/c/dam/en/us/solutions/collateral/enterprise/design-zone-security/tunnel.pdf