Moreover the questions such as the laying speed of copper hawser is slow and period is long make that " final one kilometer " of between the exchanger and user terminal has become restricting his follow - on bottle of neck question 另外，铜缆的敷设速度慢、周期长等问题，使得交换机到用户终端之间的“最后一公里”已成为制约其发展的瓶颈问题。
