The Cisco VPN 3015 Concentrator is a virtual private network (VPN) platform designed for small to medium-sized businesses that require up to full-duplex T1/E1 (4 Mbps maximum performance). The VPN 3015 offers up to 100 simultaneous IP security (IPSec) sessions or 75 simultaneous clientless sessions. Like the Cisco VPN 3005, encryption processing is performed in software, but the Cisco VPN 3015 is also field-upgradable to the Cisco VPN 3030 and 3060 models.