Communication networks can be grouped into the following categories based on the geographical locations of its computer terminals;
TYPES OF COMPUTER NETWORKS
- LOCAL AREA networks (LANs)
- Metropolitan area networks (MAN)
- WIDE AREA networks (WANs)
- Wireless local area network (WLAN)
- Wireless Wide area network (WWAN)
- International network (Internet)
Local Area Network (LAN)
A local area network is a network that connects computers and other devices within a small geographical area such as a room or a building, home a school or a computer laboratory. The devices are interconnected using a medium such as cables or a wireless medium
Types /categories of local Area Networks (Network Models or architectures)
There are two categories of local area network models or architectures;
Peer-to-peer networks
Clients-server networks
This is an interconnected group of equal computers where there is no hierarchy among them, each computer acts as both a client and a server to others on the network.
Peer to peer Configurations
Characteristics of peer to peer network
All computers access resources equally.
Each computer stores files on its own storage devices.
Each computer has its own network operating system and application software.
It normally connects less than 10 computers together.
It is suitable for home and small scale business users
Each computer has resources it shares with others on the network.
Advantages of a peer to peer network
It is very simple/easy to setup
It is inexpensive to maintain
Do not require additional specialized network administration software
Do not require a dedicated network administrator.
Disadvantages of a peer to peer network
They are not easy to administer
Each user must be trained to perform administrative tasks
Reduced performance because all the devices share resources equally
It doesn‘t allow remote installation of software
It lacks security due to absence of a server.
It’s not appropriate for big networks (cannot be used for big networks).
Clients-server networks
This is a type of local area network that consists of a central computer (the server) on which other computers (clients) are connected. The central computer providing services to client computers
Characteristics of client server network
It can connect more than 10 computers
It requires a network administrator to manage the network
The server controls communication and shared network resources.
NETWORK SERVER
A server (Network server) is a computer on a network that controls and manages the network resources, making them available to its clients (computers connected to it).
Client Computer
Client computer is one that is connected to the Network server to receive services from the server.
Advantages of Client-server network
It offers a reliable centralized storage and sharing of files.
It ensures high security of the network through access controls installed on the server.
It is easy to monitor the network performance on the server
It is easy to solve network problems.
It’s cheap to install software which can be done on the server alone instead of all computers on the network.
Disadvantages of client-server network
It’s expensive to setup.
Extra expenses on buying a server computer
Extra expenses on hiring a network administrator
The server is one point of failure. In case the server fails to work, the whole network comes to a standstill
NB:
The major difference between peer – peer and client – server network lies in how the data and information is stored.
Metropolitan Area Networks (MAN)
A metropolitan Area network is a computer network that connects two or more local area networks together which are geographically separated but in the same city.
Routers, switches and hubs are the hardware devices used to create metropolitan Area network.
Wide Area Networks (WANs)
A wide area network is a network that connects two or more local area networks together over a large geographical distance such as across districts, cities or regions. WANs make use of a wider variety of communication media compared to LANs including Telephone lines, Microwave links (wireless), Satellite connections and fiber optic cables
Wireless local area network (WLAN)
Wireless local area network is a type of network that connects computers and other devices provides in a small geographical using wireless distribution methods such as radio signals, infrared or microwave or Bluetooth to communicate between the workstations and other devices.
Examples of wireless local area network devices are;
Wireless adaptor/card
Wireless Access Point
Wireless Bridge
Wireless router
Antennae
Wireless adaptor/card is a device that provides an interface between the network operating system and an antenna to create a wireless connection to the network.
Wireless Access Point (WAP) is a device that connects wireless communication devices together to form a wireless network. For a computer to be able to communicate with wireless device, it must have a wireless network adaptor.
N.B Access Point (AP) is a wireless equivalent of a hub that receives buffers, and transmits data by means of a wireless antenna between wireless local area network and a wired network
Wireless Bridge (outdoor local area network bridge) is a device used to connect local area networks in different buildings.
Antenna is a structure made of metal rods or wires which receives and sends out radio and television signals.
Wireless Local Area Network (WLAN) topologies
Wireless Local Area Network can be built with one of the following topologies:
Peer- to – Peer (Ad hoc) topology
Access Point – based topology
Point –to– Multipoint bridge topology
Peer –to- Peer (ad hoc) topology
This is a type of topology where devices are configured to communicate directly to each other.
Access point – based topology
This is a type of topology where access point(s) are used to enable a wireless device to communicate with any other wired or wireless device on the network.
Access points are used to bridge traffic onto a wired or wireless backbone, or where network devices are interconnected using access points.
Access points
Point – to – multipoint bridge topology
This is a wireless local area network topology where a wireless bridge is configured to connect a LAN in one building to a LAN in another building even if the buildings are not close together but within a clear line of sight.
Wireless Wide area network (WWAN)
This is a wireless network over a wide area in which separate areas of coverage are connected wirelessly.
Examples of Wireless Wide Area Networks equipments especially long distance wireless
Satellite
Microwave dishes
Microwave antennae
Wireless application Protocol (WAP)
The Wireless Application Protocol (WAP) refers to a group of related technologies and protocols widely used as a standard protocol in providing Internet access to mobile phones or other small mobile devices.
International network (Internet)
Internet is an International/global interconnection of computer networks. It is described as a network of networks; it is a global network where all LANs (both big and small) worldwide are interlinked. These networks connect together in many different ways to form the single entity that we know as the Internet. In fact, the very name comes from this idea of interconnected networks.
