TOPIC 3- PFE

• Local Area Network - communication network that interconnects a variety of data communicating devices within a small geographic area and broadcasts data at high data transfer rates with very low error rates.
• LAN - appeared first in the 1970s, its use has become widespread in commercial and academic environments.
• Functions of LAN - file serving
• FUnctions of LAN - database and applications serving, print serving, electronic mail.
• Functions of LAN - remote links, video transfers, process control and monitoring and distributed processing.
• Advantages of LAN - hardware and software sharing, workstation survival during network failure and component and system evolution.
• Advantages of LAN - heterogeneous mix of hardware and software, and access to other LANs , WANs and mainframe computers.
• Disadvantages of LAN - complexity, maintenance costs, and the fact that the network is only as strong as the weakest link.
• Common technologies in LAN - ethernet and wi-fi.
• Examples of LAN - networking in home, in office, in school, laboratory, university campus.
• Examples of LAN - networking between two computers.
• Wide Area Network (WAN) - a communications network that spans a large geographic area such as across cities, states our countries.
• WAN - they can be private to connect parts of a business or they can be more public to connect smaller networks together.
• WAN - the easiest way to understand what a WAN is to think of the INTERNET as a whole, which is the world's largest WAN.
• WAN - the internet is a WAN because through the use of ISPs, it connects lots of smaller local area networks (LANs) or metro are networks (MANs).
• Since WANs, by definition, cover a larger distance than LANs, it makes sense to connect the various parts of the WAN using a Virtual Private Network (VPN).
• VPN - provides protected communications between sites, which is necessary given that the data transfers are happening over the internet.
• Although VPNs provide reasonable levels of security for business uses, a public internet connection does not always provide the predictable levels of performance that a dedicated WAN link can. This is why fiber optic cables are sometimes used to facilitate communicate between the WAN links.
• Wireless LAN or Wireless Local Area Network - refer to a Local Area Network that does not need cables to connect the different devices. Instead, radio waves and IEEE 802.11 are used to communicate
• IEEE - Institute of Electrical and Electronics Engineers
• IEEE 802.11 - name for a series of protocols for wireless networking. There are referred to as Wireless LAN, WLAN, or Wi-Fi.
• IEEE 802.11 - such a protocol allows computers that have the needed radio parts to communicate with each other, without a cable.
• Benefits of Wireless LANs - People can access the network from where they want; they are no longer limited by the length of the cable.
• Benefits of Wireless LANs - Some places and vehicles have Wireless LANs. This means that people can access the internet even outside their normal work environment, for example when they ride a train
• Benefits of Wireless LANs - Setting up a wireless LAN can be done with one box called wireless access point or wireless router. This box can handle many connections at the same time. Wired networks require cables to be laid.
• Wireless access or wireless router - setting up a wireless LAN can be done with one box. It can handle many connections at the same time.
• Wired Networks - requires cables to be laid.
• Benefits of Wireless LANs - access points can serve a varying number of computers.
• Disadvantages of Wireless LANs - Wireless LANS use radio waves to communicate. Special care needs to be taken to encrypt information.
• Disadvantages of Wireless LANs - the signal is noisier than on wires, and more bandwidth needs to be spent on error correction.
• Metropolitan Area Network (MAN) - a large computer network on the large geographical area that include several buildings or even the entire city (metropolis).
• MAN - geographical area of the MAN is larger than LAN, but smaller that WAN.
• MAN - includes many communicating devices and provides the Internet Connectivity for the LANs in the metropolitan area.
• MAN - used to combine into a network group located in different buildings into a single network.
• Diameter of MAN - range from 5 to 50 kilometers.
• MAN Rule - MAN does not belong to any particular organization, in most cases, a group of users or a provider who takes charge for the service own its connecting elements and other equipment.
• Storage Area Network (SAN) - specialized, high-speed network that provides block-level network access to storage.
• Use of SAN - improve application availability and enhance application performance.
• Use of SAN - increase storage utilization and effectiveness and improve data protection and security.
• SANs also typically play an important role in an organization's Business Continuity Management (BCM) activities.