Data Communication And Networking Sample Assignment

Ethernet and Switching techniques

TCP/IP and OSI Protocols

Data communication and networking

Question 1

Packet switching

Packet switching was developed in 1960 which refers to the dividing of data into small packets and then being sent. (Copeland, 2000)The packets are sent to their destination and are reassembled at the destination side according to their sequence numbers. Each packet consists of a separate header and IP address and body that contains the data. The packets are exchanged or transmitted between different routers located at places. The routers pass on the packet to other one depending on the routing algorithm.

Advantages

The advantages of packet switching are as follows

• Reliability

There is no danger of data loss using packet switching, because when the data arrives at the destination it is sequenced properly. If any packet is repeated or is missing it can request the sender to resend the packet.

• Economical

Packet switching is very economical because it does not require private lines. Each data packet contains the information of its destination and can de transmitted to various destinations.

• Efficiency

It provides efficiency as packet switching selects the best route for data transfer. It identifies the faults and notifies of any data loss and the delivery of messages.

Disadvantages

No continuous stream

One of the disadvantages of packet switching is that the data is not transferred in a continuous way. The packets are sent in blocks which requires more time because they are also to be assembled at the other point

• Voice messages

It has a major disadvantage in the delivery of voice messages. When the packets will arrive at different times to the destination then there will be delays and ultimately poor quality

• Corrupted data

The data sent from the sender can be corrupted during the transmission. This will result in delays and loss of data.

Circuit switching

Circuit switching refers to the communication in which two nodes establish connection at two sides and form a circuit. It remains until the data is being communicated and guarantees full bandwidth. It is mostly used for telephone calls in which two people establish a connection and it lasts till the call ends (Circuit Switching and Packet Switching Networks, 2012)

Advantages

• Performance

One of the advantages of circuit switching is that it has a guaranteed communication path. When the communication is established once, it works in a relatively fast way.

• Simple abstraction

Circuit switching allows reliable communication between the hosts when the communication is established.

• Low per packet overhead

This method does not require each packets IP address and header; it is simple and easy to use

Disadvantages

• Set up

Circuit switching requires a proper setup which is time consuming and requires experienced people.

• Single point of Failure

If the communication is failed at a single point then the whole data is lost. One point of failure destroys the whole network.

• Blocked connections

Circuit switching is not reliable for everyone, it does not support every communication  if the resources are not enough

Question 2

Advantages of layering

The advantages of layering are

• Decomposition of layers

TCP/IP layering decomposes or divides the entire communication into layers which manages the problems more efficiently and relatively (Tim Parker, 2002)

• Interoperability

The use of layering in TCP/IP model allows different types of networks and computers to communicate with each other. This shows that it is flexible and easy to use

• Managed and less burden

In TCP/IP different layers perform different tasks. This does not burden a single layer and every layer performs its tasks in a good and managed way.

• Change of network

By layering network can easily be changed without modifying anything else. This provides flexibility to the network. It becomes easy when new services are added.

Question 3

Management of loss and misplacement of packets

The data sent through the network is divided into small packets. The IP layer assigns a sequence number to every packet and assigns a destination number too. By assigning the destination number the packets are not misplaced and reach their destination. If the packets are lost, it identified by the destination at the receiver side and can request the packet again.

Sender

A sender is a device that sends the data. It sends the packets of data with their sequence numbers and destination addresses. The sender attaches a header with each packet which helps it in finding the destination. The sender IP address is also included so that’s the destination must know who sent it. The packet is transmitted to the router, then the router routes it to the destination.

Router

A router is a device between the sender and receiver that routes the packets to its destination. The router on receiving the packet sends it to the receiver by using the routing tables and algorithms. It has no information about the packet other than the destination address (Router, 2014)

Receiver

A receiver is a device that receives data. It receives the packets and then sequences them according to their sequences number. The sequence number of packets helps the receiver to arrange the packets in a order. The receiver knows the sender by knowing the senders address in the IP packet.

Therefore, the packets pass through three levels to reach it s destination. The IP layer keeps track of the packets sent. By following these three steps data can be transmitted in a proper and manageable way without the loss of data.

Bibliography

Circuit Switching and Packet Switching Networks. (2012, June 5). Retrieved AUgust 2016, 2016, from TCP/IP guide : http://www.tcpipguide.com/free/t_CircuitSwitchingandPacketSwitchingNetworks.htm 

Copeland, L. (2000, March 20). Packet-Switched vs. Circuit-Switched Networks. Retrieved August 2016, 21, from Computer world: http://www.computerworld.com/article/2593382/networking/networking-packet-switched-vs-circuit-switched-networks.html 

Router. (2014, June 5). Retrieved August 21, 2016, from Computer hope: http://www.computerhope.com/jargon/r/router.htm 

Tim Parker. (2002, August 23). Retrieved August 21, 2016, from Inform it: http://www.informit.com/articles/article.aspx?p=28782