A local area network (LAN) is a group of microcomputers located in the same general area. It covers a clearly defined small area, such as an office, home network ,one floor or work area, a single building, or a group of buildings. While a metropolitan area network (MAN) connects LANs and BNs located in different areas to each other and to WANs. MANs typically span between three and 30 miles. For example a large university may have a network so large that it may be classified as a MAN. The MAN network usually exist to provide connectivity to local ISPs, cable tv, or large corporations but will not extend beyond the boundaries of a town, city, or metropolitan area.Thus, a MAN lets two remote nodes communicate as if they were part of the same local area network. A MAN usually consists of a number of interconnected LANs and WANs. [Dennis, A. & Fitzgerald, J. (2009), p.31. Business data communication and networking. Wiley]
Also LAN are usually connected by Ethernet cables,have high speed connections and relatively inexpensive while MAN are often interconnected wirelessly using microwave radio links or fiber-optics and provide moderately fast transmission rates but can prove costly to install (very expensive).
14. Explain how a message is transmitted from one computer to another using layers?
In a network of computers each computer connected must have a unique IP address.
IP: 1.2.3.4 IP: 5.6.7.8
When a message is sent from one computer to another, it travels down the protocol layers of the model, and then up the layers of the stack on the other computer. The application layer is the application software used by the network user. The Transport Layer guarantees that the receiver gets the data exactly as it was sent. It is responsible for delivering messages from a specific process on one computer to the corresponding process on the destination computer, it can also detect
References: [Dennis, A. & Fitzgerald, J. (2009). Business data communication and networking. Wiley] [http://en.wikipedia.org/wiki/ITU-T] [http://www.citap.com/documents/tcp-ip/tcpip006.htm]