Cisco ASA 5520 Licenses
License Function
Base Software License Support for 4 10/100/1000 MB interfaces, 1 10/100 MB interface,
25 VLANs, 2 security contexts, and 300 IPSec VPN peers
VPN + Software License Support for 4 10/100/1000 MB interfaces, 1 10/100 MB interface,
25 VLANs, 2 security contexts, and 750 IPSec VPN peers