The Cisco VPN 3005 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) and offering support for up to 200 simultaneous IP security (IPSec) sessions or 50 simultaneous clientless sessions. Encryption processing is performed in software. The Cisco VPN 3005 does not have built-in upgrade capability.