The network processing engine or network services engine maintains and executes the system management functions for Cisco 7200 series VXR routers. Also, the network processing engine or network services engine shares the system memory and environmental monitoring functions with the I/O controller.Cisco 7200 VXR routers also support the NSE-1, which consists of two modular boards: the processor engine board and the network controller board. The NSE-1 Parallel eXpress Forwarding (PXF) processor works with the routing processor to provide accelerated packet switching, as well as accelerated IP Layer 3 feature processing.The NPE-100 and NPE-150 have an R4700 microprocessor that operates at an internal clock speed of 150 MHz.