In the United States, the backbone is composed entirely of fiber-optic cable (described more fully below), with bandwidths ranging from 155 Mbps to 2.5 Gbps.

• 在美国，主干完全由光缆(在文下更完整地描述)组成，其带宽从155兆比特/秒到2.；5吉比特/秒。