c. MAN (Metro Area Network)

LAN – A group of computers in close proximity to each other such as in an office, buil – 
  ding, a school, or a home. A LAN is useful for sharing resources like files, printers,
  games or other applications. A LAN in turn often connects to other LANs, and to
  the or other WAN.



WAN – A WAN spans a large geographic area, such as a state, province, or country. A
  WANs often connect multiple smaller networks, such as LANs or metro area net-
  work MANs.



MAN – A high speed network that can carry voice, data and images at up to 200 Mbps
  or faster over distance of up to 75 km. A data communication network that covers
  a larger than a campus area network (WAN) interconnects two or more LANs
  and usually covers an entire metropolitan area, such as a large city and its 
  suburbs.

Two major type of network operating systems

1. PEER TO PEER – A network of two or more computers that used the same program
  to communicate and share data. Each computer or peer is cons-
  idered equal in terms of responsibilities and each as server to 
  others in the network. Unlike a client/server architecture, a dedi -
  cated file server is not required. However , network performance
  generally not as good as under client/server especially under
  heavy loads.


Advantage: 

. Less initial expense – No need for a dedicated server.
.  Setup – An operating system (such as Windows XP) already in place may only need
  to be reconfigured the peer to peer operations.

Disadvantage:

.  Decentralized – No central repository for files and applications.
.  Security – Does not provide the security available on client/server network.

2. CLIENT/SERVER – Allow the network to centralized functions and applications in one
  or more dedicated servers. The file server become the heart of 
  the system. Providing access to resource and providing security.
  individual work stations (client) have access to the resource avai –
  lable on the file servers. The network operating system provides
  the mechanism to integrate all the components of the network and
  allow multiple users to simultaneously share the same resources
  irrespective of physical location. Novell netware and windows 
  2000 server are the example of the client/server network o.s.

Advantage:

•  Centralized – Resources and Data security are controlled the server.
• Scalability – Any or all elements can be replaced individually as needs increase.
• Flexibility – New technology can be easily integrated into system
• Interoperability – All components (client/server/network) work together
  
• Accessibility – Server can be access remotely and across multiple platform.

Disadvantage:

•  Expense – Requires initials investment in dedicated server.
• Maintenance – Large networks will require a staff to ensure efficient operation.
• Dependence – When server goes down, operations will cease across the network.