Middle Mile

What It Means

The middle mile is the network segment connecting local ISP facilities (central offices, cable headends, wireless towers) to the broader internet backbone at regional aggregation points and Internet Exchange Points. Middle mile infrastructure is typically long-haul fiber, carrying aggregated traffic from many homes and businesses back to major urban peering points and transit providers. In urban and suburban areas, middle-mile capacity is abundant, multiple competing fiber carriers (Lumen, Zayo, Crown Castle, Uniti, Windstream Wholesale) provide wholesale transport at low unit prices. In rural areas, middle-mile fiber can be scarce or monopoly-controlled, and the cost of backhaul becomes a significant fraction of a rural ISP's per-subscriber economics. A rural WISP or CLEC may pay $500 to $2,000 per month for a 1 Gbps middle-mile link that an urban ISP could obtain for $200 to $500. Middle-mile gaps can bottleneck speed even when last-mile infrastructure exists, a rural fiber ISP with gigabit last-mile capability connected to a 1 Gbps middle-mile uplink serving 1,000 customers cannot deliver gigabit to any individual customer during peak hours. NTIA's Middle Mile Broadband Infrastructure Grant Program, authorized under the Infrastructure Investment and Jobs Act at $1 billion, awarded $980 million in grants in June 2023 to 35 projects across 35 states and territories to address these gaps, building or upgrading roughly 12,000 miles of middle-mile fiber. Successful middle-mile expansion materially improves rural Broadband Grade scores over time by enabling last-mile providers to deliver advertised speeds during peak.

Frequently Asked Questions