170 Part 3 · Data Communications and Networking Our "show must go on" industry needs robust, secure networks that are "deterministic" (able to deliver data in a predictable amount of time), because the audience demands performance and reliability from our systems that far exceeds their own experience with similar technolo- gies (i.e., cell phones). At the same time, the physical environment backstage is not kind: show equipment gets abuse that can exceed what might be found in many factory or military envi- ronments (think about dragging networking cabling through the mud after a circus). Network performance is also critical for our applications--if that light cue goes in 100 ms today and 2 seconds tomorrow, a show could be ruined. So, in the early 1990s, when network use grew prevalent in our industry, we pushed to develop industrial-grade systems from top to bottom. However, we simply cannot compete with the value offered by the economies of cost and scale found in the massive consumer and business networking equipment markets, even though technologies for those applications were gener- ally designed with (low) cost and connectivity as primary concerns, and (historically, any- way 1 ) reliability and performance somewhere further down the criteria list. Fortunately, the larger information technology (IT) industry has found an ever-increasing number of "mission critical" applications similar to our own, and we are now adopting these new technologies nearly as fast as they become available (and we have even been involved in the creation of new technologies 2 ). W HAT I S A N ETWORK ? Point-to-point interfaces (discussed in "Point-to-Point Interfaces," on page 159) are designed primarily to connect two or maybe a few devices together. Point-to-point connections require direct connection from each device to every other device, so if you needed to connect a large number of devices, you would end up with an unruly mess, such as the one pictured. While this structure allows any device to commu- nicate with any other, it would be a cabling and interfacing nightmare and nearly impossible to manage. 1. Modern technologies such as Voice over IP (VoIP) have dramatically reshaped the performance requirements of modern business networks. 2. In fact, people from our industry are now involved from the outset with some of these new technologies. For example, Steve Carlson, a member of the development team for the first computerized lighting console used on Broadway and one of the originators of DMX, chaired the IEEE 802.3af standards group, which developed the Power over Ethernet (PoE) standard (covered on page 199). The fact that someone from the entertainment tech- nology business contributed in such a significant way to the development of a major computing industry stan- dard shows that our little industry has matured enough to get some notice from the "big boys." Carlson said that he got involved through ESTA at the request of the larger Ethernet standards effort, because "ESTA is consid- ered the expert in the use of Ethernet in nontraditional and hostile environments." AB