ISRO CSE 2017 | Question: 30

Question

If there are $n$ devices (nodes) in a network, what is the number of cable links required for a fully connected mesh and a star topology respectively

• A. $n(n-1)/2$, $n-1$
• B. $n$, $n-1$
• C. $n-1$, $n$
• D. $n-1$,  $n(n -1)/ 2$

Comments

Option A is correct.

Answer 1

A) n(n-1)/2 and n-1

Comments

In a full mesh topology, every computer in the network has a connection to each of the other computers in that network. The number of connections in this network can be calculated using the following formula (n is the number of computers in the network): n(n-1)/2

https://www.computerhope.com/jargon/m/mesh.htm

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@Manoja

How you get n(n-1)/2 cables for mesh topology?

expln plz

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its only when duplex mode
 

Answer 2

Mesh : Edges can be taken in nC2 = n(n-1)/2 cables

Star :  1 node is connected to remaining nodes and the are (n-1) remaining nodes which required : (n-1) cables

Comments

For star topology there are some prestigious websites where the answer is n, can we please confirm?

Answer 3

A) n(n-1)/2 and n-1

Answer 4

(n (n-1))/2, n

Comments

n-1 b'cz central controller is also consider as device.

Answer 5

Ans (A)

Take one simple example of n = 4

 

If asked, Ring topology = n 

               Bus topology  = 1