T o the traveler, the border crossing is invisible: no armed guards, snarling guard dogs, passport checks, or luggage searches. To the signals crossing this border, it might as well not even exist; but to your network man- agers and technicians, it’s a critical crossing. The border is the demarcation point, or “demarc,” between your fiber network and that of your ser- vice provider. On the outside, the service provider handles maintenance; on the inside, the responsibility is all yours. | installation Maintaining fiber-optic cable at the demarc Joel K. Matthews ADC Telecommunications Who does what at the junction of the public and private networks Network Architectures IC - Intermediate crossconnect MC - Main crossconnect PBX - Private branch exchange TC - Telecommunications closet The network architecture influences whether you should splice or connectorize fiber at the demarc. In networks with a main crossconnect near the demarc splicing is recommended a . If the fiber goes directly from the demarc to telecommunications closets it is best to use connectors at the entrance facility b . To the traveler the border crossing is invisible no armed guards snarling guard dogs passport checks or luggage searches. To the signals crossing this border it might as well not even exist but to your network managers and technicians it s a critical crossing. The border is the demarcation point or demarc between your fiber network and that of your service provider. On the outside the service provider handles maintenance on the inside the responsibility is all yours. Every installation involves tough choices. Users need service nobody wants to wait and cost is a constant issue. Faced with the competing demands for service speed and savings you may be tempted to do the job well enough for now with the rationalization that it can be fixed later. If as a network builder you find yourself asking Why not The answer is simple Y2K. The impending Y2K nightmare is a classic result of shortterm thinking. Programmers came up with what they considered a safe simple fix to a relatively small problem. They assumed that the fix would be replaced long before it in turn became an issue in its own right. In fact the fix stayed in place and became a ticking time bomb that will likely cost billions of dollars before it is resolved. In much the same way we are now in the early days of fiber networking. It may seem that we are installing enormous amounts of capacity but experience tells .
