Wide area network
The number of connected computers corresponds to the maximum of IPv4 or IPv6 . WANs span countries or even continents. WANs are used to network different LANs, but also individual computers. Some WANs are owned and used by specific organizations. Other WANs are set up or expanded by Internet service providers in order to be able to offer access to the Internet .
A WAN works on the physical layer and the data link layer of the OSI reference model . Because of the large number of connected computers, sending unaddressed information ( broadcasting ) to all computers is hardly efficient. Therefore, data is only sent to the recipient. A uniform addressing scheme is necessary for this. In addition, there must be intermediate systems that forward the data packets sent to the correct address. Such intermediate systems are switches , packet switches , bridges and routers .
WAN technologies include IP / MPLS and Ethernet , but also technologies such as plesiochronous digital hierarchy (PDH), synchronous digital hierarchy (SDH), the outdated Asynchronous Transfer Mode (ATM) and X.25 .
- Wolfgang Schulte: WAN - Wide Area Network. Introduction to technology and protocols. VDE, Berlin / Offenbach 2014, ISBN 978-3-8007-3587-7 .
- ITWissen.info: WAN (wide area network)