The MODEM converts the service provider’s longer-distance optical or electrical signals into the typical Ethernet wiring and Wi-Fi connectivity inside the home. Providers generally use one of five methods—forms of last-mile connectivity—to connect from a local facility to a home:
• Gigabyte passive optical network (GPON) is a standard for carrying network packets over a fiber network. GPON is a passive optical network because the home does not require high-powered optics to support high data rates. Wave division multiplexing (WDM) and time-division multiplexing (TDM) are used to support (up to) 64 users on a single fiber run.
• Data Over Cable Service Interface Specification (DOCSIS) is a set of standards for carrying network packets over a cable television network. DOCSIS essentially “steals” several video channels, splitting them off to carry network data. Version 3.0, which can provide up to 10 Gb/s to the customer (downstream) and 1 Gb/s from the customer to the provider (upstream), is the most commonly deployed version of DOCSIS.
• Satellite uses a small satellite dish directly mounted to a home or pole to provide Internet service.
• Fixed Wi-Fi uses specialized Wi-Fi antennas and signaling to extend the range of Wi-Fi, making it practical to replace cables between the curb and house with a wireless signal.
• Fixed cellular wireless uses 4G and 5G cellular technology to provide Internet connectivity.
The last two kinds of connections are often called fixed wireless access (FWA).
Physical Connections to the Home
There are two kinds of physical connections in most homes:
• GPON, most modern satellite connections, and FWA all look like standard Ethernet using an EJ-45 connection in the home.
• Older satellite and DOCSIS connections require a coaxial cable using some variant of the F connector, shown in Figure 11-4.
Figure 11-4 Coaxial F Connector
One significant difference between these connection methods is how data is carried between the home and provider; Figure 11-5 illustrates.
Figure 11-5 Data and Media Streams
DOCSIS connections carry data and media streams as separate channels; the MODEM splits these two streams, so
• Televisions and tuners connect to an F connector on the MODEM.
• Phones connect to an RJ-11 phone jack on the MODEM.
• The local router connects to an Ethernet RJ-45 jack on the MODEM.
While a physical failure in the network can cause all three signals to stop working, each stream can stop working independently of the other streams in other failure modes.
GPON, FWA, and other home connections provide only an IP connection. Video, voice (telephone), and other services are converted to IP network streams and carried as data packets over the connection. If IP fails, all the services fail.