The Cisco 3600 Series Router Virtual Private Network Modules (VPN Modules) optimize the platforms for virtual private networks (VPNs). The Cisco 3600 Series VPN Modules provide up to 10 times the performance over software-only encryption by offloading the encryption processing from the router central processing unit (CPU). Ideal for use in enterprise branch offices for connecting remote offices, mobile users, and partner extranets or service provider managed-services customer premises equipment (CPE), the Cisco 3600 Series VPN Modules delivers a rich integrated package of routing, firewall, intrusion-detection, and VPN functions. As an integral component of Cisco VPN solutions, the Cisco 3600 Series VPN Modules provide industry-standard encryption (IPSec), application-aware quality of service (QoS) and bandwidth management, together with robust perimeter security options.DES and 3DES encryption is required for all packets destined for an IPSec tunnel. The Cisco 3600 Series VPN Module encrypts data with DES or 3DES while freeing the main processor for other tasks.