rch that was mostly carried out at the IBM Research Lab in Rueschlikon, which is located outside of Zurich. The early introduction however of an open standard, coupled with the availability of off-the-shelf semi- conductor chips that implemented the basic Media Access Control (MAC) and physical layer (PHY) interface functions, helped Ethernet keep its market lead. Several other manufacturers tried to come up with their own LAN approaches until the Institute of Electrical and Electronics Engineers (IEEE) stepped in and started standardizing the landscape. IEEE 802.3 covers the original Ethernet approach (carrier sense multiple access with collision detection [CSMA/CD])2 and IEEE 802.5 covers the token ring. Vendors could now design adapters, also known as printed circuit boards (PCBs), that could be plugged into systems (for example, a departmental VAX computer) to connect devices on a LAN. As IT managers realized that the proliferation of connected users was depleting the available network segment addresses, a wider structure was created. Gateways between LAN segments and bridges started appearing between token rings and/or Ethernets. By using a straightforward lookup table mechanism, they would remain two or more address spaces apart and steer traffic to and from the appropriate destinations and sources. If users were connected inside a building, it was only a mat- ter of time before they would also require the appropriate levels of connectivity with the external world. In the late 1970s and early 1980s, visionaries of the engineering community realized that the increasing complexity of design work in the mechanical as well as the electronic and civil engineer- ing fields would require more sophisticated computer-based tools. Thus, the era of computer-aided design/computer-aided manufacturing (CAD/CAM) was born. Very complex pieces of software were developed in the electronics arena to enable users to design sophisticated integrated circuits and multilayer PCBs. Similarly, in the mechanical area, advanced tools 