A major consideration when designing an enterprise network is whether traffic at the access layer will be switched or routed toward the distribution layer. Placing multilayer switches in the access layer yields significant advantages; chief among them is the ability to fully utilize all uplinks to the distribution layer (as loops are no longer broken by STP)
Project being run out of Stanford University: NetFPGA, a Field-Programmable Gate Array (FPGA) geared toward network device development. As in, building your own hardware IP router and/or Ethernet switch. It's essentially a mini-computer with four GigE interfaces that can be installed as a PCI card.