UGC NET CSE | July 2018 | Part 2 | Question: 46

Question

Which of the following statements are true?

1. Three broad categories of Networks are
   1. Circuit Switched Networks
   2. Packet Switched Networks
   3. Message Switched Networks
2. Circuit Switched Network resources need not be reserved during the set up phase
3. In packet switching there is no resource allocation for packets

• A. $\text{i and ii}$ only
• B. $\text{ii and iii}$ only
• C. $\text{i and iii}$ only
• D. $\text{i, ii and iii}$ only

Comments

Yes, option C is correct, statement a and c are true.

In circuit switch network, the resources need to be reserved during the setup phase; the resources remain dedicated for the entire duration of data transfer phase until the teardown phase.

Answer 1

(a) its true, as we have three categories circuit switching,packet switching and message switching.

(b)its false,there must be resources  like buffer ,bandwidth etc be reserved during setup phase.

(c)-its true,in packet switching network there is no resource allocation as a packet will follow its subsequent packets.

hence option (c) is correct

Answer 2

"In packet switching there is no resource allocation for packets"--> This is also false.

Packet switching is of 2 types--> 1. Datagram

                                                    2. Virtual Circuit Switching

Virtual circuit is connection-oriented simply meaning that there is a reservation of resources like buffers, CPU, bandwidth,etc. for the time in which the newly setup VC is going to be used by a data transfer session.

For more information please refer--> https://www.geeksforgeeks.org/differences-between-virtual-circuits-datagram-networks/

So, NONE of the options given are correct, but if we consider only datagram ( which is not connection oriented) then we can go with option C.

 

Answer 3

Option (3) is correct.

In Circuit Switching a Dedicated Resources are allocated. e.g. PSTN Telephones uses circuit Switching.

In Packet Switching, No resources are allocated.

Comments

Can't say like this bcoz virtual circuit switching is a type of packet switching which needs resources to be allocated.

but if we see the best possible answer it can be C only :)