GATE CSE 2010 | Question: 55

Question

Consider a network with $6$ routers $R1$ to $R6$ connected with links having weights as shown in the following diagram.

Suppose the weights of all unused links are changed to $2$ and the distance vector algorithm is used again until all routing tables stabilize. How many links will now remain unused?

• A. $0$
• B. $1$
• C. $2$
• D. $3$

 

Answer 1

Ans is B 

now

Answer 2

Please correct the question in your text book who thinks answer should be 0

Distance between R5 and R6 is 4 and not 3 as asked in gate 2010 please correct the question

Answer 3

As DVR is same as Dijkstra algorithm, so simply make Minimum cost spanning tree and then first confirm it by manually traversing for each source to Destination to confirm that it's same as that we'll get using SSSP, as Greedy need not be Optimal, so after it just the ones not in mst will be unused.

Answer 4

the distance vector approach is employed until all routing tables settle, therefore we must check up to R5.