Before you start
Objectives: learn the names of common network architectures which we can use to connect our computers to the network.
Prerequisites: no prerequisites.
Key terms: wired, ethernet, isdn, dsl, dial-up, connection, cable, wireless
Ethernet network technology is used for Local Area Networks (LANs). Ethernet connections are used by organizations and now it is normal to use it in a home networking too. Every host on an Ethernet network needs to have an Ethernet network adapter to which we connect a piece of networking cable. That cable can be either fiber optic, coaxial or twisted pair.
The next way we can connect to a network is through ISDN, Integrated Services Digital Network. Like with Ethernet, for an ISDN connection we will have an interface on our host and with some kind of cable we will be able to connect our host to the ISDN network. An ISDN network is usually provided by our telecommunications provider or phone company. They will either run a special line to our house or they will use an existing phone line and multiplex it using broadband signaling to allow both a phone conversation and an ISDN connection to be established on the medium at the same time. It is also possible to have an Ethernet interface on our host which is then connected to external ISDN connector that is connected to our phone company.
The next type of network connection is a DSL, Digital Subscriber Line. DSL, unlike ISDN, is very widely implemented and it works similar as an ISDN line. With DSL typically we will have an external DSL interface which will be connected to our phone company trough our phone line using broadband signaling to divide phone line into multiple channels so that we can have a voice conversation at the same as DSL connection. Our host will be connected to DSL interface with Ethernet, USB or some other method.
We can also use a dial-up modem to connect to a network. Modem can be external or it can be installed as an interface on our host. We connect the modem with our telephone line (aka POTS, Plain Old Telephone Service). Our modem will connect to another system that also has modem installed. Modem takes the digital signal and converts it to analog signal (a sound signal) and then transmits it trough a regular phone line. The host on the other end receives this analog signal, the sound signal going through the phone line, and converts it back into the original binary data. Modems used to be very popular, but they had a limit in speed. Most phone lines will only support a signaling rate of about 56 kilobits per second. Compared to ISDN or DSL this is very slow.
The last type of connection is a wireless connection. Up to now, with Ethernet, ISDN, DSL and Dial-up we are dealing with some type of wire that connects our host to the network. With wireless networking we have some some type of network interface installed on the system which then transmits information using radio waves.
Ethernet network technology is used for Local Area Networks (LANs). ISDN, DSL and Dial-up is usually provided by our Internet Service Providers. Wireless connections mostly use radio waves to send data.