The modular design of the Cisco VPN 5008 Concentrators provides scalability to managed VPN services by adding encryption service processor (ESP) cards. Each ESP card supports up to 5000 simultaneous VPN connections, features a central RISC processor with dedicated engines for encryption acceleration and key generation , and an I/O interface. Internal dynamic load balancing ensures that all processors are leveraged and optimized, resulting in wire-speed throughput. Mix-and-match ESP cards allow the VPN to be optimized for specific network designs. Current ESP interface options include 10/100-Mbps Fast Ethernet, DS3, and HSSI.