User manual

xStack DES-3800 Series Layer 3 Stackable Fast Ethernet Managed Switch
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Figure 8- 13. Constructing a Shortest Path Tree
Router A
Router B
Router C
Router D
128.213.0.0
192.213.11.0
222.211.10.0
0
10
10
5
5
10
10
Figure 8- 14. Constructing a Shortest Path Tree
The diagram above shows the network from the viewpoint of Router A. Router A can reach
192.213.11.0 through Router B with a cost of 10 + 5 = 15. Router A can reach 222.211.10.0 through
Router C with a cost of 10 + 10 = 20. Router A can also reach 222.211.10.0 through Router B and
Router D with a cost of 10 + 5 + 10 = 25, but the cost is higher than the route through Router C. This
higher-cost route will not be included in the Router A’s shortest path tree. The resulting tree will look
like this: