The Cisco 7200VXR systems include a 1 Gbps midplane and up to six high-speed adapters configurable in a 7200 router when used with the new Network Processor Engine NPE-300. Using two independent 32-bit, 50 MHz, 1.6 Gbps PCI buses, the VXR systems deliver a throughput of up to 1 Gbps when used with the NPE-300. The VXR chassis support the new NPE-300 in addition to the NPE-225, NPE-200, and the supported in Cisco 7206VXR and Cisco 7204VXR. In addition, the VXR midplane includes a Multiservice Interchange (MIX), which supports switching of DS0 time slots via MIX interconnects across the midplane to each port adapter slot. The midplane and the MIX also support distribution of clocking between channelized interfaces on the Cisco 7200VXR to support voice and other constant-bit-rate applications.The MIX in the Cisco 7200 VXR provides the ability to switch DS0 time slots between multichannel T1 and E1 interfaces, much like time division multiplexing (TDM) capabilities. In the future, this will enable the Cisco 7200 VXR to switch DS0 voice channels on a T1/E1 interface on one port adapter to and from a separate voice processing port adapter. It will also enable DS0s to be switched through the Cisco 7200 VXR without any processing, a requirement in certain voice configurations. The VXR midplane provides two full-duplex 8.192 Mbps TDM streams between each port adapter slot and the MIX, which is capable of switching DS0s on all 12 8.192 Mbps streams. Each stream can support up to 128 DS0 channels. Port adapters that can take advantage of this new capability of the VXR chassis will be announced in the future. In addition to the enhanced features of higher performance, the support for NPE-300, and the addition of MIX, the VXR chassis support the same desired features of reliability of Cisco 7206VXR and Cisco 7204VXR with dual power supplies and hot insertion and removal of port adapters.