Topology

Topology:   

Topology is a map or a diagram of a network.

Types of Topology:  There are main two types of Topology-

1. Physical Topology: Physical Topology means how the network device is connected to each other.

 2. Logical Topology: Logical Topology means how the data packets transfer into a network.

Types of Physical  Topology:   There are main five types of Physical Topology-

                             
                              1. Star Topology
                              2. Bus Topology
                              3. Ring Topology
                              4. Mesh Topology
                              5. Hybrid Topology

 

     1. Star Topology- nj  Hub A_ev Switch n‡Z cÖ‡Z¨KwU Computer G Connection †`qv| A_ev Hub n‡Z Hub Zvici Kw¤úDUvi G Connection †`qv| A_©vr Hub  ev Switch n‡Z cÖ‡Z¨KwU Computer G Avjv`v Connection †`qv, hvi d‡j GKwU  Connection Fail Ki‡j I Aci Connection Gi †ÿ‡Î Zvnv cÖfve †dj‡e bv| A_©vr Aci Connection ¸‡jv wVK _vK‡e| Avgv‡`i †`‡k GB Star Topology  B me‡P‡q †ewk e¨envi nq| Twister Pair, Optical Fiber or Coaxial cable e¨envi Kiv nq| GB Topology Gi  e¨q GKUz †ewk|

Advantage: of Star Topology:

1.     Fast performance with few nodes and low network traffic.

2.     Hub can be upgraded easily.

3.     Easy to troubleshoot & isolate problem.

4.     Easy to setup & modify.

5.     Cable failure affects only a single  user.

Disadvantages of Star Topology

1.     Cost of Installation is high

2.     Expensive to use

3.     If the hub is affected then the whole network is stopped because all the nodes depend on the hub .

4.     Performance is based on the hub that is it depends on its capacity.

5.   Requires more cable

wb‡¤œ  Star Topology Gi K‡qKwU wPÎ †`qv nj-

 

wPÎ-1

wPÎ-2

wPÎ-3

wPÎ-4

wPÎ-5

 Bus topology

• Uses a trunk or backbone to which all of the compu ters on  the network connect.

• Systems connect to this backbone using T connector  s or taps.

• Coaxial cablings ( 10Base-2, 10Base5) were popular options years ago.

Advantages:                           

1  .     Does not use any specialized network equipment. 

2  .     Require less cable

3  .     Cheap and easy to implement

Disadvantage

1   .     Difficult to troubleshoot. 

.          .  A break in the cable will prevent all systems from accessing the network

.       . Network disruption when computers are added or removed

      

wPÎ-1

wPÎ-2

wPÎ-3

Ring Topology

• Logical ring

– Meaning that data travels in circular fashion from one computer to another on the network

– Typically FDDI, SONET or Token Ring technology are used to implement a ring network

– Ring networks are most commonly wired in a star configuration

• Token Ring has multi-station access unit (MSAU),equivalent to hub or switch. MSAU

performs the token circulation internally

 Advantage

1   .     Ring networks are moderately easy to install. 

2   .     Cable faults are easily located, making  troubleshooting easier                                                                              

Disadvantage

1. A single break in the cable can disrupt the   entire network.     

2.  Expansion to the network can cause  network disruption

                                                                    wPÎ-1

                                     

Mesh Topology

• Each computer connects to every other.

• High level of redundancy.

• Rarely used.

– Wiring is very complicated

– Cabling cost is high

– Troubleshooting a failed cable is tricky

– A variation hybrid mesh – create point to point

connection between specific network devices, often

seen in WAN implementation.

Advantage

1   .     Provides redundant paths between devices 

2   .     The network can be expanded without disruption to current uses

Disadvantage

1   .     Complicated implementation

2   .     Requires more cable than the other LAN topologies

wPÎ-1

                                      wPÎ-2

                                        

Hybrid Topology

A combination of two or more different topologies makes for a hybrid topology.When  

different topologies are connected to one another, they do not display characteristics of

 any one specific topology.

  wPÎ-1

  wPÎ-2

  wPÎ-3