computer network

Connection method

Computer networks can also be classified into hardware and software technology that is used for various network devices, such as optical fiber, Ethernet, Wireless LAN, HomePNA, or Power Line Communications G.hn. Ethernet connectivity using physical devices, cables to connect. Many devices are used hubs, switches, bridges and / or routers.

Wireless LAN technology is designed to connect devices without cables. These devices use radio waves or infrared signals as a transmission medium.

ITU-T G.hn technology uses existing home wiring (coaxial cable, telephone and power lines) with high speed mode (up to 1 Gigabit / S) LAN.

Wired Technologies

Twisted-Pair Wire - This is the most used medium for telecommunications. Twisted pair cables are standard telephone cables, which consist of two insulated copper wires twisted in pairs and are used to perform loud, and data transmission. Using two wires to help Crosstalk and electromagnetic induction to reduce. The size of the transmission rate of 2 million bits per second to 100 million bits per second.

Coax Cable - These cables are widely used for cable-TV systems, offices and other workplaces for LANs. Cable consists of copper or aluminum wire wrapped with an insulating layer is generally a flexible material with a high dielectric constant, which are all surrounded by a conductive layer. Layers of insulation help minimize interference and distortion. Transmission speeds range from 200 million to more than 500 million bits per second.

Fiber Optics - These cables consist of one or more thin filaments of glass encased in a protective layer. He emitted light that can travel long distances and higher speeds. Fiber-optic cables are not affected by electromagnetic radiation. Higher transmission speeds can reach one billion bits per second. The speed of fiber is hundreds of times faster than the coaxial cable and a thousand times faster than twisted pair telephone

Wireless Technologies

Terrestrial Microwave - land use terrestrial microwave transmitter and receiver. Equipment such as satellite dishes. Terrestrial microwave use low-gigahertz range, all communication is limited to line visibility. Path between relay stations, located approximately. 30 miles from each other. Microwave antennas are usually placed on top of buildings, towers, hills and peaks.

Communication satellites - satellites using microwave radio as their medium for communications, which do not depart from the Earth's atmosphere. The satellites are deployed in space, usually 22,000 miles above the equator. This orbit systems can receive and transmit voice, data and television signals.

Cellular and PCS systems - Use multiple radio communication technologies. The systems are divided into different geographical areas. Each area has a low power radio transmitter and antenna relay device for relay calls from one area to the next field.

Wireless LAN - Wireless LAN network using high-frequency radio technology similar to digital cellular technology and a low radio frequency. Wireless LAN-technology uses spread spectrum to enable communication between multiple devices in a limited area. An example of an open standard wireless radio-wave technology, IEEE 802.11b.

Bluetooth - short-distance wireless technology. Work on approx. 1Mbps range from 10 to 100 meters. Bluetooth is an open protocol for wireless exchange of data over short distances.

Wireless Web - Wireless Internet refers to using the World Wide Web through devices such as mobile phones, pagers, PDA and other portable communication devices. Mobile Web service provides always / everywhere access.

Scale(LAN,WAN,MAN,VPN,PAN,CAN,SAN)

Networks are often classified as a local area network (LAN), a global network (WAN), Metropolitan Area Network (MAN), Personal Area Network (PAN), virtual private networks (VPN), Campus Area Network (CAN), Storage Area Network (SAN) and others, depending on their size, scope and objectives. Use, self-confidence and access rights, which vary between these types of networks - such as local networks are typically designed for internal use by the internal systems of the organization and employees in different physical locations (eg construction), while the WAN can connect to physically separate parts of the organization together and may contain links to third parties.

Network topology

Computer networks can be classified in the network topology when the network is based, a bus network, Star network, Ring network, mesh network, Star-bus network, or hierarchical tree network topology. Network topology means how devices on the network see logical connections between them. The use of the term "logical" here is significant. This means that the network topology is independent of the "physical" structure of the network. Even if networked computers are physically placed in the linear regime, if they are connected through a hub network is a star topology, instead of a bus topology. In this context, visual and performance of the network to distinguish logical network topology is not necessarily the same as a physical plan. Networks can be classified according to the method of data used for data transmission, these include digital and analog networks.