Andrew S. Tanenbaum Edition 5th Exercise 5 Question 6 (Page No. 490)

Question

Consider the network of Figure. Distance vector routing is used, and the following
vectors have just come in to router C: from B: (5, 0, 8, 12, 6, 2); from D: (16, 12,
6, 0, 9, 10); and from E: (7, 6, 3, 9, 0, 4). The cost of the links from C to B, D, and E,
are 6, 3, and 5, respectively. What is C’s new routing table? Give both the outgoing
line to use and the cost.

Comments

duplicate of https://gateoverflow.in/258414/gatebook-2019-cn2-1

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for DVR

take the distance vectors

C using B (5,0,8,12,6,2)

C using D (16,12,6,0,9,10)

C using E (7,6,3,9,0,4)

C->B = 6 ; C->D=3 ; C->E=5

now see

C -> A -- using B=5+6 using D = 16+3 using E =7+6

find minimum? 11

calculate for all nodes  & see min

= (11,6,0,3,5,8)

Answer 1

C's table (-,6,0,3,5,-)

B's table (5,0,8,12,6,2)

Going from C via B [add 6 to B's table] gives (11,6,14,18,12,8)

D's table (16,12,6,0,9,10)

Going from C via D [add 3 to D's table] gives (19,15,9,3,12,13)

E's table (7,6,3,9,0,4)

Going from C via E [add 5 to E's table] gives (12,11,8,14,5,9)

Min from each table is taken

C's new table (11,6,0,3,5,8)

Outgoing line (B, B, -, D, E, B)