Networking

One way to categorize the different types of computer network designs is by their scope or scale. For historical reasons, the networking industry refers to nearly every type of design as some kind of area network. Common examples of area network types are:

• LAN - Local Area Network
• WLAN - Wireless Local Area Network
• WAN - Wide Area Network
• MAN - Metropolitan Area Network
• SAN - Storage Area Network, System Area Network, Server Area Network, or sometimes Small Area Network
• CAN - Campus Area Network, Controller Area Network, or sometimes Cluster Area Network
• PAN - Personal Area Network
• DAN - Desk Area Network                                                                                                                                                                                                                                                                                     
•                                                                                                                                                               
• LAN - Local Area Network                                                                                                                      
  
   
  
                                                                                                                                      A LAN connects network devices over a relatively short distance. A networked office building, school, or home usually contains a single LAN, though sometimes one building will contain a few small LANs (perhaps one per room), and occasionally a LAN will span a group of nearby buildings. InTCP/IP networking, a LAN is often but not always implemented as a single IP subnet.
  In addition to operating in a limited space, LANs are also typically owned, controlled, and managed by a single person or organization. They also tend to use certain connectivity technologies, primarily Ethernet and Token Ring.
                                                                                                                                                      
• WLAN - Wireless Local Area Network 
                                                                                                 
  
   
  
  
                                                                                                                                                       
  
  A wireless local area network (WLAN) links two or more devices using some wireless distribution method (typically spread-spectrum orOFDM radio), and usually providing a connection through an access point to the wider Internet. This gives users the ability to move around within a local coverage area and still be connected to the network. Most modern WLANs are based on IEEE 802.11 standards, marketed under the Wi-Fi brand name.
  Wireless LANs have become popular in the home due to ease of installation, and in commercial complexes offering wireless access to their customers; often for free. New York City, for instance, has begun a pilot program to provide city workers in all five boroughs of the city with wireless Internet access.
                                                                                                                                                                                                                                                                                      

• WAN - Wide Area Network

         
  
                         
  
                                                                                                                                                                                                                                                     As the term implies, a WAN spans a large physical distance. The Internet is the largest WAN, spanning the Earth.
  A WAN is a geographically-dispersed collection of LANs. A network device called a routerconnects LANs to a WAN. In IP networking, the router maintains both a LAN address and a WAN address.
  A WAN differs from a LAN in several important ways. Most WANs (like the Internet) are not owned by any one organization but rather exist under collective or distributed ownership and management. WANs tend to use technology like ATM, Frame Relay and X.25 for connectivity over the longer distances.
                                                                                                                                           
                                                                                                                                                                                                                                                                                                                                   
• MAN - Metropolitan Area Network                                                                                                            
  
                                             
  
                                                                                                                                                
  A metropolitan area network (MAN) is a computer network in which two or more computers or communicating devices or networks which are geographically separated but in same metropolitan city and are connected to each other are said to be connected on MAN. Metropolitan limits are determined by local municipal corporations; the larger the city, the bigger the MAN, the smaller a metro city, smaller the MAN. ^[1]

  “

  A MAN is optimized for a larger geographical area than a LAN, ranging from several blocks of buildings to entire cities. MANs can also depend on communications channels of moderate-to-high data rates. A MAN might be owned and operated by a single organization, but it usually will be used by many individuals and organizations. MANs might also be owned and operated as public utilities. They will often provide means for inter networking of local networks.

  ”

  Kenneth C. Laudan and Jane P. Laudon define a metropolitan area network as:^[2]

  “

  A Metropolitan Area Network (MAN) is a large computer network that spans a metropolitan area or campus. Its geographic scope falls between a WAN and LAN. MANs provide Internet connectivity for LANs in a metropolitan region, and connect them to wider area networks like the Internet. SAN - Storage Area Network                                                                                                                                                                                                                                                             A storage area network (SAN) is a dedicated network that provides access to consolidated, block level data storage. SANs are primarily used to enhance storage devices, such as disk arrays, tape libraries, and optical jukeboxes, accessible to servers so that the devices appear like locally attached devices to the operating system. A SAN typically has its own network of storage devices that are generally not accessible through the local area network by other devices. The cost and complexity of SANs dropped in the early 2000s to levels allowing wider adoption across both enterprise and small to medium sized business environments.

  A SAN does not provide file abstraction, only block-level operations. However, file systems built on top of SANs do provide file-level access, and are known as SAN filesystems or shared disk file systems.
   
• CAN - Campus Area Network                                                                                                                
  
                                                                                                                                                                                                         
  
                                                     
  
                                                              A campus network, campus area network, corporate area network or CAN is a computer network made up of an interconnection of local area networks (LANs) within a limited geographical area.^[1][2] The networking equipments (switches, routers) and transmission media (optical fiber, copper plant, Cat5 cabling etc.) are almost entirely owned by the campus tenant / owner: an enterprise, university, government etc.                                                                                                                                                                                                                                                                          
• PAN - Personal Area Network                                                                                                               
  
                                                                 
  
                                               
  
                                                           
  
                                                                                     
  A personal area network (PAN) is a computer network used for data transmission among devices such as computers, telephonesand personal digital assistants. PANs can be used for communication among the personal devices themselves (intrapersonal communication), or for connecting to a higher level network and the Internet (an uplink).
• A wireless personal area network (WPAN) is a PAN carried over wireless network technologies such as:
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  
•       DAN - Desk Area Network                                                                                                                                                                                                                                                                                     
  
                                                                                                                                                                                                                               
  
                                                                                                                                                                                                                                                
  The Desk Area Network (DAN) is a multimedia workstation based around an ATM interconnect (as shown in the above diagram). All communication between peripherals and even between the CPU and its main memory is achieved by sending ATM cells through a switch fabric. A prototype implementation based on the Fairisle switch fabric has been built and is being used to investigate the architecture.
  The initial paper on the Desk Area Network by Mark Hayter and Derek McAuley can be seen by clicking here. Also Mark Hayter's thesis provides a good overview of the current Cambridge ATM environment, including the current status of the DAN.
  Two other papers have been written describing aspects of the DAN, the first entitled Devices on the Desk Area Network and the second Multimedia Streams and the CPU Cache. Documents from the Blue Bookdescribing the DAN hardware are The MDH9 Processor Node and The ATM Camera V2 (AVA200). Other devices on the DAN are implemented using Fairisle Port Controllers.