Broadband network planning requires stakeholders to design optimal ways for accessing the Internet cloud and for engineering accessibility throughout a nation. Planners start by securing access to major regional and international telecommunications links and by installing a domestic Internet Exchange. Subsequently they extend the geographical scope of Internet access by constructing a domestic backbone network that provides a broadband connection between urban centers and eventually extends broadband access into the hinterland. As planners increase the penetration of broadband access into less densely populated areas, they also should pay attention to a less obvious requirement: ensuring connectivity between and among users within a metropolitan area. As urban regions spread out the tasks of ensuring metropolitan connectivity becomes increasingly challenging.

Metropolitan connectivity constitutes a possibly underappreciated goal, because users require both access to the Internet cloud and the rest of the world, but also access between and among various points within a sprawling metropolitan region. The “anchor tenants” of broadband networks typically have very large demand for bandwidth and access requirements in many different locations. For example, a multi-national corporation involved in the extraction, processing and export of natural resources typically would have broadband access requirements in remote areas, where the resources are situated, as well as other locations that process and refine the material plus regional headquarters and locations handling administrative functions. Additionally such an important user might have several facilities within a metropolitan area housing management staff who typically have broadband requirements both for interacting with other corporate personnel as well as the various organizations that support the business, e.g., bankers, attorneys, consultants, and engineering firms.

Metropolitan connectivity provides both the first and last kilometer access to the Internet cloud as well as the so-called middle mile access that links various outposts of both affiliated and unaffiliated ventures located at many dispersed locations within a country. Because not all of these users are physically near existing domestic backbone networks, carriers will need to devise ways to provide similar broadband functionality even though possibly far fewer users will require access. In light of the fact that demand may not be as robust as that for direct access to the domestic backbone, network operators cannot achieve the same scale economies and accordingly will have to charge higher rates on a per unit of capacity basis. Middle mile access typically costs more to provide thereby resulting in a commensurately higher cost to users.

Users of metropolitan broadband networks have the same “mission critical” traffic as customers located at or near a domestic backbone. As a threshold matter, they will need to assess whether to seek authority to construct and operate their own dedicated network, to rely on an existing operator to lease existing capacity, or to build new facilities to accommodate the user’s specific requirements. This “make/buy” decision depends on many factors including the price of available capacity, as well as dedicated new facilities and the ease or difficulty in securing regulatory authority to construct private facilities and to interconnect them with equipment and lines operated by incumbent carriers. If a National Regulatory Authority will not allow installation of private facilities, or imposes unreasonable terms and conditions, users with specific metropolitan broadband service requirements will have little bargaining power when resorting to negotiations with an incumbent carrier. While some users are functionally “captive” to the terms and conditions imposed by a single incumbent carrier, others can leverage the ability to relocate elsewhere to secure fair rates.  

Metropolitan network negotiations may generate high rates for users particularly when carriers cannot anticipate that other nearby users would require similar services thereby helping the carrier offset the high, initial costs incurred to accommodate the needs of one user. Network operators have to provide the same sort of service quality and reliability as available from public networks even though doing so generates higher costs when as few as one user leases capacity. Backbone operators routinely install redundant, back up capacity as well as two or more different routing options so that they can continue to provide essential service even when congestion or an outage occurs. Middle mile users have the same requirements for redundant and diverse traffic routing options.

In addition to middle mile service, metropolitan connectivity includes “backhaul” options, particularly for wireless carriers. Backhaul service provides links from remote locations, e.g., a rural cellphone tower, back to an urban location where the wireless carrier would route calls to intended call recipients including ones using the city’s wireline network.  Not all wireless carriers install both the towers needed to provide service throughout a region and the backhaul capability needed to route rural traffic to urban switching facilities and call recipients. To conserve capital and to expedite the availability of service, wireless carriers may concentrate on the installation of tower sites without the fiber optic cable or microwave radio backhaul links needed to route traffic from and to remote tower sites. Incumbent domestic wireline carriers may be expected to accommodate the back haul requirements of cellphone companies. In many nations incumbent operators are classified as common carriers having the obligation to satisfy the reasonable service requirements of end users and even other carriers. This classification typically obligates incumbent carriers to provide service even if doing so would require the installation of facilities likely to be used only by few, if any customers other than the cellphone carrier that initiated the request for service.

  • 5.6.1 Regional and Metropolitan Links

    Broadband network planners typically use a blend of wired and wireless technologies to meet the demand for middle mile and backhaul services by end users and carriers. Because the total demand for any specific link may not generate a substantial volume of traffic, network operators will need to use comparatively less expensive technologies than that used for high demand links. Wireless microwave services can provide a cost-effective solution to these lower volume “sparse route” requirements. These wireless technologies provide service to users in fixed locations, rather than the more familiar mobile services such as cellular radiotelephone service.

    Regional metropolitan links provide an example of how two broadband technologies can combine to solve specific end user requirements.  For broadband users in remote locations a single technology solution would prove too expensive. A network operator could not make a business case to extend the fiber optic domestic backbone to the remote customer, or even to install a dedicated branch unit off the backbone. Instead the carrier routes traffic via existing broadband facilities to the point closest to the remote user with sufficient population density and demand and then installs lower capacity broadband, wireless facilities to link “off network,”  remote users with the backbone. Because of the distance from the backbone such branches are not considered first and last kilometer services.

  • 5.6.2 Implementation Issues for Metropolitan Connectivity

    Metropolitan connectivity presents network planners with many challenges, because of the number of routes needed and the lack of readily available options. The importance of the domestic backbone and a possibly large rural footprint makes it more likely that carriers can quickly and economically secure the rights to install facilities. Incumbent carriers typically have a legal status that authorizes them as public utilities to demand property easement access based on “eminent domain” which favors the public interest claims of the carrier over the property rights of individual land owners. Additionally network operators may choose to locate backbone networks along existing rights or way such as that used or abandoned by railroads, electric utilities, pipeline operators and highways.      

    Middle mile and backhaul routing in more densely populated areas may trigger more difficult and time consuming rights of way acquisitions. Because much of the route may cover still densely populate terrain, the carrier cannot claim to be extending first time broadband access and the carrier may not qualify for the option of invoking eminent domain. Land owners located near a proposed tower site or conduit installation may not want the disruption and possible division of a single tract of property. In developed nations property owners have banded together to oppose network facility installations.  The phrase Not in my Back Yard (“NIMBY”) refers to the typical displeasure property owners have toward rights of way requests of public utilities and telecommunications carriers.