According to the latest Census report, 70 percent of households in the United States have at least one computer connected to the Internet, used for communication, finding news and information and other tasks like online shopping. The networks connecting one computer to another have varied over the years. While Ethernet and wireless networks are the most common today, this wasn't always the case. At one time, Token Ring was the most common. Each networking technology has its own capabilities and limitations, including data speed and range, making it useful in some situations, but useless in others.
Ethernet is the most common network technology used in local area networks and can be easily identified by the RJ-45 connectors on each of their cables, which resemble extra-wide telephone jacks. Ethernet cables, which are usually blue, yellow or red, are a little more slender than a drinking straw and have a maximum range of 328 feet. Ethernet can carry up to 10 megabits per second (Mbps), which is 10 million bits of information each second. Fast Ethernet can carry up to 100Mbps and gigabit Ethernet can carry up to 1000Mbps. Data is sent in packets, with each packet containing information to determine where the data is to be sent and a checksum that ensures that none of the data in the packet has been garbled or lost during transmission. One of the reasons Ethernet is so popular is because it supports the Transmission Control Protocol and Internet Protocol used by the Internet, a set of protocols familiarly known as TCP/IP.
Developed by IBM, Token ring was once a popular technology used in LANs before most organizations moved to Ethernet. Today it can be difficult to find. As its name suggests, computers are arranged in a ring and single token is continuously passed from computer to computer. When a computer wants to send data to another computer, it waits for the token to come around and then attaches its data to it. The token is then passed to the next computer in the ring until it reaches the recipient computer. The recipient attaches two bits of data to the token to inform the sender that the data was received. Other computers can't send data until the ring is free again. This may sound slow, but was actually lightning fast for its time - up to 16Mpbs.
Fiber Distributed Data Interface is a set of standards for transmitting data over fiber-optic cable over a span of up to 124 miles. FDDI is usually used as a backbone in a Wide Area Network (WAN), like that connecting two different buildings in the same city. FDDI is similar to old-fashioned Token Ring, but it uses two token rings: a primary ring and a secondary ring, each able to carry 100Mbps. If the primary ring is working correctly, the backup ring can also be used, doubling the capacity to 200Mbps. However, a dual ring has a maximum distance of only 62 miles. For distances greater than that, only one ring can be used at a time.
Although Wireless can refer to many technologies, in networks the most common technology used in home and offices is the 802.11 Wireless Local Area Network (WLAN), also called Wi-Fi. Access to a WLAN is controlled by a wireless access point, which is most commonly a wireless router. Any computer or wireless device -- like an iPhone, laptop or smart TV -- must request access from the access point and supply the appropriate password if requested before joining the wireless network. Currently, the fastest wireless is 802.11n technology, which can transmit up to 300Mbps. Upcoming 802.11ac technology can transfer up to 433Mbps. Although range is affected by obstructions and even atmospheric conditions, range is generally up to 230 feet indoors and 800 feet outdoors.
- Jupiterimages/Polka Dot/Getty Images