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Computer Networks - Topologies, Types of Network - LAN, MAN, WAN

What is Computer Network

Type of Network Connection

           Physical 

                    Bus Topology

                           Advantage

                           Disadvantage

                    Star Topology

                           Advantage

                           Disadvantage

                    Ring Topology

                            Adavantage

                            Disadvantage

                    MESH Topology

                            Advantage

                            Disadvantage

                    Tree Topology

                             Advantage

                             Disadvantage

                    Hybrid Topology

                             Advantage

                             Disadvantage

           Logical 

                    Bus Logical Topology

                    Ring Logical Topology

Types of Network

          PAN 

          LAN

          MAN

          WAN
                                                                                                                                                                       

 Computer Networks - Topologies, Types of             Network-LAN, MAN, WAN                                    

  What is Computer Network                                                                

 A computer network is a set of computers connected together for the purpose of sharing resources. The most common resource shared today is connection to the internet. Other shared resources can include a printer or a file server. The internet itself an be considered a computer network. 

 A computer network is a set of connected computers. Computers on a network are called nodes. The connection between computers can be done via cabling, most commonly the Ethernet cable, or wirelessly through radio waves. Connected computers can share resources, like access to the internet, printers, file server, and other. A network is a multipurpose  connection, which allows a single computer to do more.  

   Type of Network Connection                                                             

Computer networks can be broken down historically into topologies, which is a technique of connecting computers. The most common topology today is a collapsed ring. This is due to the success of a network protocol called the ethernet. This protocol, or network language, supports the internet, Local Area Networks, and Wide Area Networks, Network Topology two type 

A. Physical 

B. Logical 

  A. Physical                                                         

  i. Bus Topology 

 • In Bus topology, All the nodes (computer, Servers, Printer etc) are connected to the single cable. 

 • This cable is known as Bus and acts as backbone of the network, which joins every computer and peripheral in the network. 

 • Both ends of the shared chennel have line terminator. The data is sent is only one direction and as soon as it reaches the extreme and the terminator removes the data from the line. 

 Adramtage 

 • Bus Network are useful in small network  lik : set up in a small office. 

 • Required less cable length compared to other topologies. 

 • Easy to connect a computer. 

 • Easy to understand. 

 • Bus topology cost very less. 

 Disadvantage 

 • Entire network shuts down, if there is any break in the main cable. 

 • Cables has a limited length. 

 • It is slow when more divices are added into the network. 

 • It is slower than ring topology. 

 ii. Star Topology   

 • In star topology, Every node is connected to central node, which is called hub or switch. 

 • The central node (hub or switch) is the server and other nodes are the clients. 

 • In this topology, Data from the source node is first delivered to the hub and is then transferred to the destination nodes. 

 • It is easy to add on removes nodes in  this topology. 

 • STAR topology gives better performance  because data does not pass through every node unlike bus topology. 

 • So if particular workstation (or a node) gets an error then the entire network is not affected. But if the central wonkstation (Hub/Switch) goes down, then the entre network collapses. 

 Advantage 

 • Easy to install and modify. 

 • Hub can be upgraded easily. 

 • Easy to troubleshoot. 

 • New nodes can be added easily without affection the other nodes. 

 • If any of the local computer fails, the remaining portion of the network is unaffected. 

 Disadvantage 

 • Whole network is depend on central device so if the central device is failed than the whole network in stopped. 

 iii. Ring Topology 

 • In ring topology, all the computers (nodes) are connected in a closed loop. 

 • This topology works on the token based system and token travels in the loop. 

 • If token is free, then node can capture  the token and attach the data and destination address to the token, and then leaves the token. 

 • When token reaches at the destination node, the data is removed by the destination node and token is free to carry the next data. 

Advantage 

 • Additional components do not effect the performance of network. 

 Disadvantage 

 • The main drawback of ring topology is that if one node fails, then the complete network will go down. 

 iv. MESH Topology 

 • In mesh topology, each of node are interconnected with one another. 

 • Every node sends its own signals and also relay data from other nodes. 

 • MESH topology network can be formed by using the formula. number of cables = (n/n-1))/2 

 • There are two types of mesh topology- Full MESH Topology.- Partial MESH Topolog. 

 • In full Mesh Topology each node is connected to every other node in the network. 

 • In partial Mesh Topology some nodes are not connected to every node. 

 Advantage 

 • If one of the device (node) fails, then there is always on alternative present. 

 • Expansion and modification can be done without disrupting other nodes. 

 • Communication is very fast b/w two nodes. 

Disadvantage 

 • It is quite expensive because a higher length of cable is required. 

 • Installation and maintenance is very difficult. 

 v. Tree Topology 

 • Tree topology in the combination of Bus and star topology. 

 • A tree topology is also known as a star bus topology. 

 • The whole network is divided into segments, which can be easily managed and maintained.

Advantage 

 • Expansion of nodes is possible and easy. 

 • Other hierarchical networks are not affected if one of them gets damaged. 

 • Easier maintenance and fault finding. 

 Disadvantages  

• If the backbone line breaks, then the entire segment goes down. 

 • Huge cabling is needed. 

 • A lot of maintenance is needed. 

 • If the network becomes extremely large it becomes difficult to manage. 

 vi. Hybrid Topology 

 • It is the combination of two or more topology. 

 • Star, ring, bus topology combination. 

  B. Logical Topology                                                    

 Logical Topology means how information is passed b/w two nodes in a network. Logical Topology two type. 

 i. Bus Logical Topology. 

 ii. Ring Logical Topology 

 Types of Network                                                                                 

                                                              Computer Network 

 PAN                                     LAN                             MAN                                       WAN                           (Personal Area Network)  ( Local Area Network)  (Metropolitan Area Network)  (Wide Area Network)

 i. PAN (Personal Area Network) 

 • A Personal Area Network (PAN) is smallest network which is very personal to a user. 

 • This may include bluetooth enabled devices or infra enabled devices 

 • PAN has connectivity range up to 10 meters. 

 • PAN may include wireless computer keyboard and mouse, bluetooth enabled headphones, wireless printers and TV remotes. 

 ii. LAN (Local Area Network) 

 • LAN is a local network. 

 • A Local Area Network is a privately  owned computer network covering a small networks geographical area (small physical areas), like a home, office or building e.g. a school Network. 

 • A lan is used to connect the computers and other network devices so that the devices can communicate with each other to share the resources. 

 • They are widely used in business organsation, factories, colleges university, industry to sharing the resources suck as : files or hardware devices etc. 

 • IEEE developed specification for LAN. 

 • Data transfer speeds over a local area network can reach up to 10 Mbps (such as for ethernet network) and I Gbps (as with FDDI or gigabit ethernet). 

 iii. MAN (Metropolitan Area Network) 

 • MANs network is larger than LAM and can cover a city and its surrounding areas. 

• Generally, MAN can be create by inter connecting two LANs. 

 • MAN is made up the combination of two or more than two LANs. 

 • Geographical area cover by MAN is larger than LAN network but smaller than WAN (Wide Area Networks) networks. 

 • These networks deliver fast and efficient communication by using a high speed  carrier e.g. fibre optic cable. 

 • The best known example of MAN is a cable television networks available in whole city. 

 • A MAN can be created as a single network such as cable TV network, covering the entire city or a group of several Local Area Networks (LANs) 

iv. WAN (Wide Area Network) 

 • A wide area network (WAN) is a telecommunication network. 

 • WAN is used for communication b/w devices of a large geographical area such as : countries or contiment and uses common carriers like - satellite system, telephone line etc. 

 • A WAN can contain multiple smaller networks, such as LANs or MANs. 

 • The internet is the largest WAM spanning the earth. 

 • WANs are commonly connected either through the internet on special arrangments made with phone companies or other services providers. 

 • The speed of WAN network various depends on the cost of the companies.

                                                                     Notes                                                                

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