A computer network can be established using either a wired or wireless LAN (local area network). In a wired network, computers are physically attached to one another using Ethernet cables, with one or more "bridge" devices such as hubs, switches and routers propagating the network. Wired networks may require the main computer (the one with the modem installed) to run Internet connection-sharing software, especially on dial-up connections, to distribute the Internet signals to all computers. A typical wireless network is established using either the 802.11a, 802.11b or 802.11g standard, and a wireless router.
Establishing the Network
In a wired network, each computer must be attached to another computer or a central device using Ethernet cables. Setting up the network may be tedious, as large volumes of wire are needed, especially when computers are located in different rooms. The cables have to be wired according to predefined rules, based on variables such as mix of devices, modem type and Internet connection type. A wireless network may be set up either in ad hoc or infrastructure mode, in which the former allows communication in peer-to-peer mode, and the latter allows devices to communicate with a central node. All devices meant to access the network must be equipped with built-in Wi-Fi cards or wireless network adaptor cards to communicate with the wireless router.
Wired networks are generally superior in terms of performance and speed. Data transfer rates in a wired network can reach up to 100 Mbps (megabits per second), whereas it is only about 54 Mbps for 802.11a and 802.11g wireless networks, and 11 Mbps for an 802.11b network. A wireless network is also sensitive to distance and obstructions, meaning that devices located further from the router will receive weaker signals, which translates to slower data transfer rates. Speed of a wired network using hubs (instead of switches) may suffer when multiple devices are active on the network. The problem may be resolved by using switches.
Both wireless and wired networks can be very reliable if optimum conditions are maintained. Once configured, an established wired network rarely malfunctions, due to improvements in Ethernet cable technology that make them very robust and durable. The major drawback of a wired network is loose cables--connections tend to go down when devices are moved or the cables are exposed. Wireless networks are free of the problems associated with Ethernet cables, but the network's signal strength may fluctuate, especially when physical objects obstruct the radio signals. Wireless signal strength may also vary due to interference from appliances such as cordless telephones and microwave ovens.
Both wired and wireless networks have certain drawbacks in different aspects of security. Wired LAN equipment generally does not support security measures such as firewalls, meaning that security software has to be installed on individual computers. Wireless networks are, in theory, less secure because the signals travel in air and may be intercepted by individuals with Wi-Fi devices in the vicinity. Modern wireless networks use security standards such as WEP (Wired Equivalent Privacy) and WPA (Wi-Fi Protected Access) to restrict unauthorised access and protect privacy.
Wireless network equipment is more expensive than wired network equipment. Hardware components such as Ethernet cables and switches are relatively inexpensive, and the software required for connection sharing may be obtained for free. Wireless equipment such as routers and wireless cards are comparatively more expensive.