Classical Data Transfer Systems
Local and wide area networks based on classical wire and wireless solutions form the basis for the development of advanced IT systems. The proper selection of active equipment, identification of proper transmission media (copper, fiber optics, radio transmission) affect directly the project costs.
Classical Networks
These networks use, as the transmission medium, well known and controlled connections over copper links and fiber optic connections, the operators infrastructure and radio connections (unlike wireless networks, these are point-to-point connections replacing links equivalent to other communication methods). Depending on the tasks fulfilled by particular networks and their geographical coverage, classical networks can be divided into:
LAN (Local Area Networks)
covering one or more directly interconnected buildings. Those networks use data transmission technologies of the highest capacities owing to small transmission distances (transmissions used currently in practice are as fast as up to 10Gb/s).
MAN (Metropolitan Area Networks)
interconnecting networks that enable communication between LAN structures located in one city. Generally, MAN networks can be said to operate where connections between LANs can be established with relatively fast connections and using technologies also available in LAN networks - Gigabit Ethernet, Fast Ethernet, Ethernet or ATM. Such networks use dedicated connections which are not shared with other networks as it is in the case of WAN structures.
WAN (Wide Area Networks)
connecting numerous LAN or MAN networks or other WAN networks. They are characterized by large distance connections and specific network technologies applied to achieve the required transmission parameters. A feature distinguishing those networks from others is also the fact that in most cases connections through the telecommunications service provider's infrastructure are used for communication purposes. Such infrastructure is shared by many clients hence the requirement to apply specific solutions to ensure uniformity of transmission, its security, quality, etc.
"Paralle" Systems
Wired networks intended for purposes usually quite far from data transmission technologies, but suitably adapted by the application of additional equipment and technologies for computer data transmission. Cable television and electricity supply cables can serve as examples. The need to adapt them to data transmission stems primarily from a very extended infrastructure which serve as a transmission medium (the cabling in a building for cable television TV or electric tractions). The original application of these two example technologies is quite far from data transmission, but the use of two-way amplifiers for the television signal in the case of cable television, and the PLC (Powerline Communications) technology in electrical traction, together with the appropriate active equipment network elements with interfaces allows for connection to the infrastructure, enables fast transfer of data to the end user.
Wireless LAN (WLAN)
WLAN (Wireless LAN) are LAN networks in which radio or infrared connections are used for data transmission. WLAN users operate within an area covered by broadcasting/receiving equipment which makes the constructed network independent of physical connections. |
