Question

In packet switched network, store and forward refers to

		transmitting packet to the next link after entire packet arrives at router
		scheduling of packet transmission to avoid congestion
		transmitting packet to the next link while router is receiving the packet
		storing entire packet at router until acknowledgment is received

Which of the following HTTP methods allows a user to upload an object to a specific path on a Web server?

		HEAD
		GET
		PUT
		POST

Which of the following is NOT a host?

		Laptop
		Packet switch
		Web proxy server
		Web server

Which of the following is NOT a layer of the Internet protocol stack?

		Communication
		Network
		Link
		Application

Which of the following statements is NOT correct about retransmission in reliable data transfer protocol?

		Sender retransmits if the packet or ACK was overly delayed.
		Sender retransmits if a data packet was lost.
		Sender retransmits if an ACK was lost.
		Sender retransmits if it receives a duplicated ACK.

Which of the following is NOT one of the four sources of packet delay?

		Propagation delay
		Transmission delay
		Configuration delay
		Queueing delay

A user requests a Web page that consists of one HTML and two images. With non-persistent HTTP, how many RTTs, in addition to the object transmission time, are required for this page?

		6
		5
		4
		3

Answer 1

Solution:- Packet switching means transferring the data in the form of packets, to a network...and it uses store and forward technique while transferring the packets..

Q) Which of the following HTTP methods allows a user to upload an object to a specific path on a Web server?

A) It's POST (why because,the above 4 (HEAD,PUT,POST,GET are most commonly used HTTP methods, but as per the question POST method allows user to upload an object on a web server. where as PUT Is for create/update a resource, GET is for retriving information from server, HEAD is for same as GET, but, it transfers line and header section and lastly POST Is for, to send data to the server like file upload, or any user/customer information etc)

Q)Which of the following is NOT a host?

A) See, Firstly a host can be defined as any device that can be able to communicate with other devices or network. and it also consists of some ip address...so, laptop can be host because, it can be connected of packet switches and a network of communication skills. i guess, packet switch is the answer

Q)Which of the following is NOT a layer of the Internet protocol stack?

A) (given, Communication, Network, Link, Application) so,

Communication is not a layer of internet protocol stack and the layers of internet protocol stack are applicatio layer,transport layer,network layer,data link and physical layer.

Q)Which of the following statements is NOT correct about retransmission in reliable data transfer protocol?

A) given options are Sender retransmits if the packet or ACK was overly delayed,  Sender retransmits if a data packet was lost. ,  Sender retransmits if an ACK was lost ,  Sender retransmits if it receives a duplicated ACK.

retransmission means sender have to resend the packet to reciever in case of any mistakes / lost of packets are occured. so, Sender retransmits if the packet or ACK was overly delayed, is the answer.. delay must be less than 0.5 sec and it shouldn't be excessively delayed..

Q)Which of the following is NOT one of the four sources of packet delay?

A)in packet switching, there are 4 types of delays, queuing, transmission,propagation and processing. so, configuration delay is the answer.

Q)A user requests a Web page that consists of one HTML and two images. With non-persistent HTTP, how many RTTs, in addition to the object transmission time, are required for this page?

A) formula =>  total time = 2RTT+transmit time

(for each image 2 RTT is required 1 for image 1 for tcp connection so, for 2 images = 2*(2 RTT) = 4 RTT

total time = 2 RTT + 4 RTT = 6 RTT so, '6'...!!!