Figure 1 shows that the 9000VPN is powered by a Brecis MSP2006 Multi-Service Processor clocked at 170MHz. The MSP2006 is a MIPS-based microcontroller designed for access points and wireless routers which includes two 10/100 Ethernet PHYs and a PCI bus interface. It doesn't however, contain a hardware encryption co-processor, which you'll see later affects its performance as an IPsec endpoint.
Figure 1: MU-9000VPN board
(click on the image for a full-sized view)
Both the WAN and LAN ports appear to be handled by a switch chip whose identity hides under the heatsink that you can see in the board photo. The USB 2.0 ports are courtesy of a VIA Vectro VT6212 USB 2.0 Host Controller and 8MB of flash and 32MB of RAM perform the memory chores.
Note that the same board, loaded with a mini-PCI connector and equipped with a FiWin WM680-110 PRISM-based radio, becomes a WMU-9000VPN. The connector mounts in the spot at the lower left of the photo where you see the empty connector pads.