我国经过多年的建设,骨干网带宽已经比较丰富,宽带接入手段多样化,网络瓶颈已从骨干网逐渐转移到城域网上。骨干网上丰富的带宽资源要落地,效益和利润的增长点必须通过城域网这个关口。目前在骨干网上有很多“darkfiber”(暗光纤),只有通过城域网的建设,才能尽可能多地“点亮”埋在地下的暗光纤。随着社会信息化需求的进一步提升、运营商拓展 After many years of construction in our country, the backbone network bandwidth is already abundant, and broadband access means are diversified. The network bottleneck has gradually shifted from the backbone network to the metropolitan area network. The backbone of the rich bandwidth resources to the ground, the growth point of efficiency and profit must pass through the metro this gateway. Currently there are many “darkfiber ” (dark fiber) in the backbone network, only the dark fiber buried in the ground can be “lit up” as much as possible through the construction of metropolitan area network. With the further promotion of social information needs, operators expand