Show the initial routing tables for each of the nodes u, v, x, y, and z.

Question

Consider the network shown in Figure 2. Initially, each node only knows the costs of the links to each of its own neighbors. Based on the distance-vector algorithm, show the initial routing tables

for each of the nodes u, v, x, y, and z.

U -> V (1)

U -> Y (2)

Y -> X (3)

V -> X (3)

V -> Z (6)

X -> Z (2)

Answer 1

In a network using the distance-vector routing algorithm, initially, each node constructs its routing table based solely on the direct links it has to its neighbors. The routing table entries typically include the destination node, the cost to reach that node, and the next hop node along the path to the destination.

Given the network topology and link costs you provided, here's how the initial routing tables would look for each node u,v,x,y,u,v,x,y, and zz. We'll start by listing the direct neighbors and known costs for each node:

1. Node uu:
2. vv with a cost of 1
3. yy with a cost of 2
4. Node vv:
5. uu with a cost of 1
6. xx with a cost of 3
7. zz with a cost of 6
8. Node xx:
9. vv with a cost of 3
10. zz with a cost of 2
11. yy with a cost of 3
12. Node yy:
13. uu with a cost of 2
14. xx with a cost of 3
15. Node zz:
16. vv with a cost of 6
17. xx with a cost of 2

Initial Routing Tables

Here are the detailed routing tables for each node:

Node uu:

Destination Cost Next Hop

uu 0 -

vv 1 vv

yy 2 yy

xx ∞ -

zz ∞ -

Node vv:

Destination Cost Next Hop

vv 0 -

uu 1 uu

xx 3 xx

zz 6 zz

yy ∞ -

Node xx:

Destination Cost Next Hop

xx 0 -

vv 3 vv

zz 2 zz

yy 3 yy

uu ∞ -

Node yy:

Destination Cost Next Hop

yy 0 -

uu 2 uu

xx 3 xx

vv ∞ -

zz ∞ -

Node zz:

Destination Cost Next Hop

zz 0 -

vv 6 vv

xx 2 xx

uu ∞ -

yy ∞ -