11/8/20

Networking Fundamental Part 2

 

 

DATA COMMUNICATION AND NETWORKING


 

5. NETWORKING FUNDAMENTALS(Part-2)

    An overview of networking

    Switching techniques: -

    a.   Circuit Switching 

    b.   Packet Switching

    c.    Message Switching

    Network Topologies: -

    a.   Bus Topologies

    b.   Ring Topologies

    c.   Star Topologies       

 

Network Topologies: -

1. The arrangement through which computer system all network devices are connected to each other is called network topology.

2. It may define both physical and logical aspects of the network.

3. Logical and physical topologies could be same or different in a same network.

 

                         (Click on image for clear view)

 

 

BUS TOPLOGY: -

1. In bus topology in long cable acts as a backbone to link all devices in the network.

2. Nodes are connected in the bus topology by drop line and cables.

3. Bus topology uses less cabling than mesh and star.

4. Bus topology was one of the first topology which was used in designing Ethernet.

5. Bus topologies faces problem while multiple host sending data at the same time.

6. Bus topology is one of the simple forms of networking where if value of a device does not affect the other devices.

7. In bus topology failure of the shared communication line can make all other devices stop functioning.

 

                      (Click on image for clear view)


 

Advantages: -

1. In bus topology if and devices are connected to each other then the number of cables required to connect them is only 1.

2. Cost of the cable is less as compared to other topology and it can use only for small networks?

Disadvantages: -

1. In bus topologies if the common cable fails the whole system will crash down.

2. It will increase collisions in the network if the network traffic is heavy.

 

 

RING TOPOLOGY: -

1. In ring topology each nodes is linked to only its immediate neighbour.

2. There is a token in ring topology which is circulating in the ring all the time.

3. There is a monitor which manages the operation of token.

4. Ring topology used in number of repeaters with a large number of nodes.

5. In ring topology repeaters is used because if someone wants to send some data to the last node in the ring topology with 100 nodes then the data will have to pass through 99 nodes, hence to prevent Data loss repeaters are used in the network.

                             (Click on image for clear view)


 


Ring topology can perform following operations: -

1. The responsibility to perform the operation is taken by one station which is known as monitor.

2. Station has to hold token if it wants to to transmit the data after the transmission is done the token is to be released for other stations to use

3. The token will be circulating in the ring if no station is transmitting the data.

4. Two types of token releasing techniques are used early token release and delayed token release

Early Token Release: -Early token releases the token just after the transmitting the data whereas,

Delayed Token Release: -Delayed token releases the token after the acknowledgement is received from the receiver

Advantages: -

1. In ring topology the possibility of Collision is minimum.

2. It is cheap to install and easily expandable.

Disadvantages: -

1. Troubleshooting is difficult in ring topology.

2. Addition and removal of stations between ring topology disturb the whole topology.

START TOPOLOGY: -

1. All nodes in star topology are connected to a central point called Hub (Passive network device like extension board) which connects them into the communication channel.

2. There is a dedicated path between node and Centre Hub that is nodes are not directly connected to another node unlike mess topology.

3. Connections are in such manner that n number of end devices or nodes required n number of wires to connect.

4. Central hub controls communication between all the nodes, if one node wants to send data to another it send data to the hub then hub relay the data to the connected node.

5. Star topology is basically used for local area network and less expensive than mesh topology.

 

                              (Click on image for clear view)


 

Advantages: -

1. Setup of star topology is very easy because, if N devices are connected to each other then number of cables required to connect them is N.

2. It is less expensive and each device required only one port that is to connect to the hub.

Disadvantages: -

1. Unless it is less expensive but its installation cost is high.

2. Performance of star topology is based on the single concentrator that is hub.

3. If the central hub fails the whole system will crash down.

 

 

TREE TOPOLOGY: -

1. Tree topology also known as hierarchical topology and it is the variation of star topology.

2. This is the most common form of network topology which is used presently.

3. It inherits the properties of bus topology and copies as extended star topology.

4. Tree topology divides the network into multiple levels or layers of a network.

5. In LAN's  a network is divided into three types of network devices: -

a. Lowermost layer

b. Middle layer and

c. Highest layer

Lowermost (Bottom) is access layer where computers are attached.

Middle layer is known as distribution layer which works as a connector or mediator between upper layer and lower layer.

The highest layer is known as core layer and it central point of network that is root of the tree from which all nodes hanger.

 

                                    (Click on image for clear view)


 

 

Advantages: -

1. Tree allows more devices to be attached in a single Centre hub therefore it increases the distance that is travelled by the signal to come to the devices.

2. Tree allows the network to get isolate and also important from different computers.

Disadvantages: -

1. In trees in the central hub gets fails the entire system will fail.

2. Because of cabling tree setup cost is higher.

 

 

MESH TOPOLOGY: -

1. In mesh topology each and every node connected with another node via particular device.

2. In mesh topology if, N numbers of devices are connected with each other then total number of ports required by each device is (N-1). In diagram there are 5 devices then number of ports required by each device is 4.

3. Total number of dedicated links required for connect them in mesh topology is N(N-1)/2. In figure there are 5 devices then total number of cables or links required 5(5-1)/2 = 10.

                                          (Click on image for clear view)

 

Advantages: -

1. Mesh topology provide security and privacy and it is durable topology.

2. mesh topology is highly secured because there is a dedicated path between any two nodes

3. In mesh topology data is reliable because data is transferred among the devices through dedicated channels or link.

Disadvantages: -

1. Installation and configuration of mesh topology is difficult.

2. It is suitable for less number of devices because cost of cables is high and bulk wiring is required.

3. Mesh topology is costlier and maintenance cost of these topologies is also high.

 

HYBRID TOPOLOGY: -

1. Structure whose design contains more than one topology is said to be a hybrid topology.

2. Hybrid topology inherits advantages and disadvantages of all the incorporating topologies.

 

                                (Click on image for clear view)


 

 Networking Fundamentals Part-1 (Click me>>)

 Official Site: - https://www.diplomaincs.in/

Thank you all.

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5 comments:

  1. Language is too easy to understand...thank you sir for providing us notes..

    ReplyDelete
  2. Thank you sir for notes, it's too easy to understand...

    ReplyDelete
  3. Thanks a lot sir..for giving us these understandable notes.

    ReplyDelete

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