在网络领域,总有一些公司准备推出新的东西来增加带宽。就象如今热门的同步光纤网络(Synchronous OpticalNetwork,SONET)、混合光缆、xDSL、密集波分多路、无线宽带一样,这么多的名词使人头晕目眩,在进行带宽投资时无从选择。 当然,带宽的增加也会导致成本的迅速增加。在宽带领域,成本的增加通常是由于传输器件导致的。例如在Internet中,从一个城市传送到另外一个城市的 In the networking arena, there are always companies that are going to roll out new things to increase bandwidth. Just as the popular Synchronous Optical Network (SONET), hybrid cable, xDSL, Dense Wavelength Division Multiplexing, and wireless broadband today are so daunting that there is no alternative for making bandwidth investments. Of course, the increase in bandwidth can also lead to a rapid increase in costs. In the field of broadband, the cost increase is usually caused by the transmission device. For example in the Internet, from one city to another city