As Internet usage across the nation has expanded in recent decades, the state has taken an interest in ensuring that public schools have Internet service. The state’s main reasons for desiring schools to have Internet service relate to improving instructional delivery, transmitting accountability-related data to the state, and, more recently, administering online tests. This article answers many questions the Legislature has raised in recent years about how schools access the Internet. It describes five key aspects of schools’ Internet connections — (1) physical infrastructure, (2) connection speeds, (3) Internet service providers, (4) devices used to display Internet content, and (5) networking equipment.

School Internet Connections

Internet Infrastructure

Infrastructure Refers to the Physical Connections From Schools to the Internet. The type of infrastructure connecting schools to the Internet varies. Schools use primarily copper telephone lines, coaxial cables, and fiber-optic cables. Less commonly, schools use satellites and cell phone towers.

  • Copper Telephone Lines. Copper telephone lines can be used to connect schools to the Internet in two ways. With a dial-up connection, the telephone line can be used for either phone calls or Internet activity but both cannot be performed at the same time. With a digital subscriber line (DSL), the telephone line can be used for both phone calls and Internet activity at the same time. Telephone lines typically run above ground along telephone poles, though in some cases they can be underground.

  • Coaxial Cables. Coaxial cables, which transmit cable television, also can be used to connect schools to the Internet. The same coaxial cable can be used for television and Internet activity simultaneously. Coaxial cables are brought into school buildings through utility poles or underground lines.

  • Fiber-Optic Lines. Fiber-optic lines are another means of connecting schools to the Internet. These lines transmit Internet content exclusively. They can be installed above ground or underground.

  • Satellites. Satellites in space also can connect a school to the Internet. Because signals are transmitted through the air, no wiring is needed outside the school site.

  • Cell Phone Towers. Similar to satellites, cell phone towers can transmit Internet data through the air to a school without the need for wiring to the school.

Internet Speeds

Different Types of Internet Infrastructure Support Different Internet Speeds. Internet speeds are measured by the number of “bits” (or units of data) transmitted per second. Generally, slow speeds are measured in thousands of bits per second (kilobits, or Kbps), medium speeds in millions of bits per second (megabits, or Mbps), and fast speeds in billions of bits per second (gigabits, or Gbps). As shown in Figure 1, copper telephone wires provide the slowest maximum Internet speeds, while fiber-optic lines provide the fastest maximum speeds.  

Different Schools Require Different Internet Speeds. The Internet speed requirements at a school depend on (1) how many students and staff typically access the Internet at one time and (2) the complexity of their Internet usage. For example, to administer the new Smarter Balanced Assessment Consortium tests, the consortium estimates that speed requirements will vary greatly depending on the number of students taking the test. As shown in Figure 2, the speed requirements for the tests increase proportionately to the number of students taking the tests, such that a school with 1,000 students requires speeds ten times faster than a school with 100 students. Because speed requirements vary for the test, infrastructure requirements also vary. If a school has greater than 7,500 students, it likely would need fiber-optic Internet infrastructure to administer the tests. Schools with fewer students likely would be able to use either coaxial cable or copper telephone wiring. (This assumes no other Internet usage at the school at the time of test taking.)

Internet Service

Schools Typically Receive Internet Service Through a Combination of Providers. In most cases, schools using wired Internet infrastructure receive their Internet service from two Internet Service Providers (ISPs). One ISP is the non-profit Corporation for Educational Network Initiatives in California (CENIC), with whom the state contracts for a portion of Internet service on behalf of schools statewide. The other ISP typically is a commercial company (such as AT&T or Comcast) responsible for providing the remainder of the service. Figure 3 shows the multi-stage process for how schools connect to the Internet using ISPs. This process also is described in more detail below. (Because schools using wireless infrastructure, such as satellites or cell phone towers, connect to the Internet in a single stage, they purchase Internet service from a single ISP.)

School-Site Connections Provided by Commercial Providers. At a school site, commercial providers’ infrastructure connects different buildings and classrooms together. For example, a large school site using DSL might have a copper telephone line owned by AT&T running from outside the school site to a central distribution point on the school premises. From the central distribution point, AT&T’s copper telephone wires would run to each building and, within each building, copper wiring would run to each classroom.

Last-Mile Connections Provided by Commercial Providers. Commercial companies also typically provide the infrastructure leaving the school site—known as a “last-mile connection.” This infrastructure carries Internet data between the school site and a high-speed Internet backbone (discussed below) and typically passes through the school’s district office. For example, a school might pay AT&T for last-mile service that uses its copper telephone lines. The Internet speed of a computer at the school is determined by the speed of this last-mile connection. 

High-Speed Backbone Provided by CENIC or Commercial Provider. The last-mile connection typically connects to a high-speed backbone—fiber-optic cables that run across very large distances. Most schools in California connect to the Internet through a backbone owned by CENIC. These schools pay a commercial provider for their last-mile connection but the state pays for their use of the CENIC backbone. (As displayed in Figure 3, in order to access the CENIC backbone, schools’ last-mile connections must pass through their county offices of education.) Schools not using the CENIC backbone pay a commercial provider for both their last-mile connections and use of their commercial providers’ backbones.

The Internet Consists of Interconnected High-Speed Backbones. The Internet is not owned by a single entity. Rather, it is a physical “network of networks” owned by multiple entities (typically private companies). These networks have agreements to allow Internet traffic to flow among them.


Schools Must Have Certain Devices to Access Internet Content. Schools purchase various devices that display Internet content and allow them to send and receive information. Figure 4 describes the most common devices.

Networking Equipment

Networking Equipment at a School Site Connects Devices to the Internet. Equipment also allows multiple devices to access the Internet simultaneously. Figure 5 describes these main types of equipment used by schools.