T1: Stabilization has just completed. (All DVs as per the data given in question)
T2 : The change in distance from 6 to 2 has occurred. i.e between 2 rounds. (The next round of updates will occur at T3)
As soon as this change takes place the only nodes affected are N2 and N3. Their updated DVs become
Rest all DVs for N1,N4 and N5 remain unaltered.
T3: A round of update occurs.
N1 [currently (0,1,7,8,4)] gets DV of N2(1,0,2,7,3). Hence updates to (0,1,4,8,4)
N2 : gets DVs from N1 [old (0,1,7,8,4)], N3[ altered (7,2,0,2,6)] and N5(old (4,3,6,4,0)). Changes may occur only
corresponding to N3. final N2 (1,0,2,4,3)
N3: gets DVs from N2 [ altered (1,0,2,7,3)] and N4 [old (8,7,2,0,4) ]. Hence changes only corresponding to N2.
Final N3 (3,2,0,2,5) : Answer to first part.
N4 : gets DVs from N3[ altered (7,2,0,2,6)] and N5 [old (4,3,6,4,0)] : Final DV (8,4,2,0,4)
N5 : gets DVs from N4[old(8,7,2,0,4)] and N2[ altered(1,0,2,7,3)] : final (4,3,5,4,0)
<< 2nd Part >>
The cost of link N2−N3N2−N3 reduces to 22 (in both directions). After the next round of updates, the link N1−N2N1−N2 goes down.
so and end of T3 one round of updates has completed and now the link between N1 and N2 breaks
T4 : N1 to N2 weight becomes INF. N2 updates Immediately
N2 : (INF,0,2,4,3)
N1 should change as well but nothing mentioned about it in question, also not relevant
T5 : Next round of updates start. (Will focus on N3 only)
N3[ current state (3,2,0,2,5) ] gets DVs from N4[old (8,4,2,0,4) ] and N2 [altered (INF,0,2,4,3)].
So it seems there is no change for N3. Shouldn't the answer be 3