After the update in the previous question, the link N1-N2 goes down. N2 will reflect this change immediately in its distance vector as cost, . After the NEXT ROUND of update, what will be the cost to N1 in the distance vector of N3? A) 3 B) 9 C) 10 D) $\infty$

Official answer: C) 10. Explanation: From the previous update round: - In the previous round, N3 sent its old distance vector (7, 6, 0, 2, 6) to its neighbors. - N4 sent its distance vector (8, 7, 2, 0, 4) to its neighbors. - N2 sent its distance vector to N3, which N3 used in the previous question to become (3, 2, 0, 2, 5). Now, between rounds, the link N1-N2 goes down: - N2 immediately sets its cost/distance to N1 to in its local distance vector before the new exchange, or discovers it upon failure. - In this round of exchange: - N3 receives the distance vectors from its neighbors N2 and N4. - N2's distance to N1 is . - N4's distance to N1 is 8 (from N4's vector: (8, 7, 2, 0, 4)). Now node N3 recomputes its distance to N1: DN3(N1) = \ c(N3, N2) + DN2(N1), \; c(N3, N4) + DN4(N1) \ DN3(N1) = \ 2 + , \; 2 + 8 \ = ( , 10) = 10 Thus, the new cost to N1 in the distance vector of N3 is 10. Therefore, option C is the correct choice.

Computer Networks · Distance Vector and Link-State Routing

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GATE CSE 2011 Q53 · MCQ · 2 marks

After the update in the previous question, the link N1-N2 goes down. N2 will reflect this change immediately in its distance vector as cost, $\infty$ . After the NEXT ROUND of update, what will be the cost to N1 in the distance vector of N3?

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Distance Vector and Link-State Routing

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How GATE tests Distance Vector and Link-State Routing

GATE tests Distance Vector (DVR) and Link State Routing (LSR) through two primary lenses: step-by-step mathematical trace of Bellman-Ford vector updates and conceptual comparison of protocol implementations (RIP vs. OSPF). 2-mark questions focus on iterative distance vector computations after link cost changes or link failures, including routing loop and count-to-infinity dynamics. 1-mark questions evaluate protocol architecture, transport layer encapsulation, algorithmic complexity, and convergence properties.

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After the update in the previous question, the link N1-N2 goes down. N2 will reflect this change immediately in its distance vector as cost, $\infty$ . After the NEXT ROUND of update, what will be the cost to N1 in the distance vector of N3?

Select an option to check

Key concept

Distance Vector and Link-State Routing

Step-by-step verified solution

Examiner trap & misconception

Topic notes

How GATE tests Distance Vector and Link-State Routing

Full Distance Vector and Link-State Routing guide →

After the update in the previous question, the link N1-N2 goes down. N2 will reflect this change immediately in its distance vector as cost, $\infty$ . After the NEXT ROUND of update, what will be the cost to N1 in the distance vector of N3?

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After the update in the previous question, the link N1-N2 goes down. N2 will reflect this change immediately in its distance vector as cost, $\infty$ . After the NEXT ROUND of update, what will be the cost to N1 in the distance vector of N3?

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After the update in the previous question, the link N1-N2 goes down. N2 will reflect this change immediately in its distance vector as cost, ∞\infty∞. After the NEXT ROUND of update, what will be the cost to N1 in the distance vector of N3?

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After the update in the previous question, the link N1-N2 goes down. N2 will reflect this change immediately in its distance vector as cost, $\infty$ . After the NEXT ROUND of update, what will be the cost to N1 in the distance vector of N3?

After the update in the previous question, the link N1-N2 goes down. N2 will reflect this change immediately in its distance vector as cost, $\infty$ . After the NEXT ROUND of update, what will be the cost to N1 in the distance vector of N3?