Nothing is middling about the middle mile

The US broadband industry has been invigorated thanks to several US federal government programs to deliver broadband Internet to unserved and underserved households across the country, particularly in rural areas. The largest and most high profile initiative is Broadband Equity Access and Deployment (BEAD), which has allocated $42.5 billion in funds for broadband access and prioritizes fiber optic access to the home.

But a state-of-the-art fiber access network is just an isolated island without the intermediate network that connects it to the core and the wider Internet. Called the "middle mile" because of its location between "last mile" access and the service provider's core, this network is an essential — though sometimes overlooked — component of a fiber broadband strategy.

The US Middle Mile Program is the main government funding program for middle mile network buildouts. Like BEAD, it focuses on reaching unserved and underserved areas and will largely address rural areas. As of September 2023, the National Telecommunications and Information Administration (NTIA) announced that the full $1 billion in funding had been awarded to 36 organizations across US 40 states and territories. Additionally, some portion of BEAD funding will be used to build out middle mile networks when service providers show that new middle mile infrastructure is required to reach customers.

Middle mile requirements

As a segment focused on aggregation and transport, capacity is naturally a big requirement. The middle mile typically demands fiber optic connectivity, with DWDM used as a capacity multiplier when fiber is scarce (and it usually is). Connectivity can be at 1G, 10G or 100G data rates — or possibly higher.

Rural broadband speeds have been severely limited due to the physical limitations of DSL. But BEAD sets the broadband minimum threshold at least 100Mbit/s downstream, and as noted earlier, it favors fiber. Average bandwidth consumption will increase exponentially in BEAD-served areas. Another key factor in capacity will be the number of households served per central office or hub, particularly as homes passed are converted to homes actively served.

Beyond capacity, distance and geography are two other important considerations. The term "middle mile" does a good job of positioning the segment relative to the last mile access networks that it serves, but it is also a bit misleading. Distances can be quite long, particularly in the rural buildouts that are the primary focus of BEAD. In extreme cases, these distances can run several hundred miles as network traffic traverses large states to reach the core. Additionally, routes may be across difficult geographies, including mountains, rivers, remote areas or even subsea routes. Active equipment must be housed outdoors, far away from the controlled environments of central offices, hubs or data centers, and may be difficult for technicians to reach.

Last but certainly not least is cost. BEAD-related broadband builds will be in areas that have historically lacked a business case. Federal government funding aims to make broadband investment economical, but the service providers must plan their builds accurately. They must also consider upfront the required middle investments for fiber broadband. Otherwise, the middle mile may ultimately sink the entire plan.

Time for innovation

New optical innovations are emerging that can help with all the requirements. Heavy Reading believes a new generation of coherent pluggable optics at 100G data rates (dubbed 100ZR) will be a big one, as the technology addresses capacity, distance and economics all at once. But more suppliers are needed. Outdoor hardening is another product requirement for pluggable optics and systems, including different types of housing, such as strand-mountable. On the software side, network automation can speed turn-up and cut operations costs, particularly for equipment in difficult-to-reach locations.

Beyond hardware and software, business models may also need to evolve to make broadband economics work. Consortia formed to share middle mile networks across multiple service providers represent examples that are just beginning to emerge.

Network X Americas

Service providers have many decisions to make and much planning to do for the next-generation middle mile network. Fortunately, Network X Americas, an event taking place from May 21 to 23 in Dallas, will provide a forum where the industry can learn, educate, discuss and debate what's needed. I am excited to moderate a panel on this topic titled "Developing the Middle Mile Network" on May 22. And I expect middle mile considerations to surface in several other sessions, including "What are the ins and outs of BEAD?" (May 23) and "Feasting on Fiber & PON" (May 22).

For more information or to register to attend Network X Americas, click here.

Editor's note: Informa owns Light Reading, Heavy Reading, Omdia and the Network X conference series, which this commentary promotes.