Wide area network WAN

Wide area network (wan) is a communications network that covers a wide geographical area. Such as a country or the world A WAN may use a combination of satellites fibre optic cable microwave and copper wire connections and link a variety of computer from mainframe to terminal if a LAN connect computer together at a signals site then a wan connects computer across large distance at multiple sites WANs may utilize public leased or private communication equipment usually in combination and can span an utilize number of miles A WAN would be most useful for large companies with office or factories in widely separated areas across the world.
Mesh topology
In a Mesh topology every device has advantage a dedicated point to point link to very other devices. The dedicated means that the link carries traffic only between the two devices it connected A fully connected mesh network therefore has n physical channels to link n devices To accommodate that many links every device On the network must have n.1 input out ports Mesh topology is usually implemented in a limited fashion for example a backbone connecting the man computer of a hybrid network that can include several other topology show mesh network
Star Topology
In a star network each nodes computer or other devices is directly connected to the central computer or Hub that provides connection points for node on the network The star topology is the common topology in use today in star network information or data is communicated from one computer to another through Hub. This from of network configuration looks like a star as shown in
CDMA
CDMA stands for code Division Multiple Access it is a technique used for digital communication and wireless is a a channel access method used by various radio communication technologies. This allows several users to share a band of frequencies
The following example explains the concept of CDMA.
There is a single room (channel) in which many people wish to talk to each other simultaneously. To avoid confusion, people could take turns speaking (time divisions) speak at different pitches (frequency divisions) or speak different languages (code Division) CDMA is analogue to the Last example Where people speaking the same language can understand each each other. Similarly
In radio each group of users is given a shared code. Many code occupy the same channel but only users associated with a particular code can communicate.